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commit e7b691b085fda913830e5280ae6f724b2a63c824 upstream.
slab_node() could access current->mempolicy from interrupt context.
However there's a race condition during exit where the mempolicy
is first freed and then the pointer zeroed.
Using this from interrupts seems bogus anyways. The interrupt
will interrupt a random process and therefore get a random
mempolicy. Many times, this will be idle's, which noone can change.
Just disable this here and always use local for slab
from interrupts. I also cleaned up the callers of slab_node a bit
which always passed the same argument.
I believe the original mempolicy code did that in fact,
so it's likely a regression.
v2: send version with correct logic
v3: simplify. fix typo.
Reported-by: Arun Sharma <asharma@fb.com>
Cc: penberg@kernel.org
Cc: cl@linux.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
[tdmackey@twitter.com: Rework control flow based on feedback from
cl@linux.com, fix logic, and cleanup current task_struct reference]
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Mackey <tdmackey@twitter.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit b104a35d32025ca740539db2808aa3385d0f30eb upstream.
The page allocator relies on __GFP_WAIT to determine if ALLOC_CPUSET
should be set in allocflags. ALLOC_CPUSET controls if a page allocation
should be restricted only to the set of allowed cpuset mems.
Transparent hugepages clears __GFP_WAIT when defrag is disabled to prevent
the fault path from using memory compaction or direct reclaim. Thus, it
is unfairly able to allocate outside of its cpuset mems restriction as a
side-effect.
This patch ensures that ALLOC_CPUSET is only cleared when the gfp mask is
truly GFP_ATOMIC by verifying it is also not a thp allocation.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Alex Thorlton <athorlton@sgi.com>
Tested-by: Alex Thorlton <athorlton@sgi.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hedi Berriche <hedi@sgi.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 7f88f88f83ed609650a01b18572e605ea50cd163 upstream.
Commit 248ac0e1943a ("mm/vmalloc: remove guard page from between vmap
blocks") had the side effect of making vmap_area.va_end member point to
the next vmap_area.va_start. This was creating an artificial reference
to vmalloc'ed objects and kmemleak was rarely reporting vmalloc() leaks.
This patch marks the vmap_area containing pointers explicitly and
reduces the min ref_count to 2 as vm_struct still contains a reference
to the vmalloc'ed object. The kmemleak add_scan_area() function has
been improved to allow a SIZE_MAX argument covering the rest of the
object (for simpler calling sites).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 0253d634e0803a8376a0d88efee0bf523d8673f9 upstream.
Commit 4a705fef9862 ("hugetlb: fix copy_hugetlb_page_range() to handle
migration/hwpoisoned entry") changed the order of
huge_ptep_set_wrprotect() and huge_ptep_get(), which leads to breakage
in some workloads like hugepage-backed heap allocation via libhugetlbfs.
This patch fixes it.
The test program for the problem is shown below:
$ cat heap.c
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#define HPS 0x200000
int main() {
int i;
char *p = malloc(HPS);
memset(p, '1', HPS);
for (i = 0; i < 5; i++) {
if (!fork()) {
memset(p, '2', HPS);
p = malloc(HPS);
memset(p, '3', HPS);
free(p);
return 0;
}
}
sleep(1);
free(p);
return 0;
}
$ export HUGETLB_MORECORE=yes ; export HUGETLB_NO_PREFAULT= ; hugectl --heap ./heap
Fixes 4a705fef9862 ("hugetlb: fix copy_hugetlb_page_range() to handle
migration/hwpoisoned entry"), so is applicable to -stable kernels which
include it.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Guillaume Morin <guillaume@morinfr.org>
Suggested-by: Guillaume Morin <guillaume@morinfr.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit b1a366500bd537b50c3aad26dc7df083ec03a448 upstream.
shmem_fault() is the actual culprit in trinity's hole-punch starvation,
and the most significant cause of such problems: since a page faulted is
one that then appears page_mapped(), needing unmap_mapping_range() and
i_mmap_mutex to be unmapped again.
But it is not the only way in which a page can be brought into a hole in
the radix_tree while that hole is being punched; and Vlastimil's testing
implies that if enough other processors are busy filling in the hole,
then shmem_undo_range() can be kept from completing indefinitely.
shmem_file_splice_read() is the main other user of SGP_CACHE, which can
instantiate shmem pagecache pages in the read-only case (without holding
i_mutex, so perhaps concurrently with a hole-punch). Probably it's
silly not to use SGP_READ already (using the ZERO_PAGE for holes): which
ought to be safe, but might bring surprises - not a change to be rushed.
shmem_read_mapping_page_gfp() is an internal interface used by
drivers/gpu/drm GEM (and next by uprobes): it should be okay. And
shmem_file_read_iter() uses the SGP_DIRTY variant of SGP_CACHE, when
called internally by the kernel (perhaps for a stacking filesystem,
which might rely on holes to be reserved): it's unclear whether it could
be provoked to keep hole-punch busy or not.
We could apply the same umbrella as now used in shmem_fault() to
shmem_file_splice_read() and the others; but it looks ugly, and use over
a range raises questions - should it actually be per page? can these get
starved themselves?
The origin of this part of the problem is my v3.1 commit d0823576bf4b
("mm: pincer in truncate_inode_pages_range"), once it was duplicated
into shmem.c. It seemed like a nice idea at the time, to ensure
(barring RCU lookup fuzziness) that there's an instant when the entire
hole is empty; but the indefinitely repeated scans to ensure that make
it vulnerable.
Revert that "enhancement" to hole-punch from shmem_undo_range(), but
retain the unproblematic rescanning when it's truncating; add a couple
of comments there.
Remove the "indices[0] >= end" test: that is now handled satisfactorily
by the inner loop, and mem_cgroup_uncharge_start()/end() are too light
to be worth avoiding here.
But if we do not always loop indefinitely, we do need to handle the case
of swap swizzled back to page before shmem_free_swap() gets it: add a
retry for that case, as suggested by Konstantin Khlebnikov; and for the
case of page swizzled back to swap, as suggested by Johannes Weiner.
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lukas Czerner <lczerner@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 8e205f779d1443a94b5ae81aa359cb535dd3021e upstream.
Commit f00cdc6df7d7 ("shmem: fix faulting into a hole while it's
punched") was buggy: Sasha sent a lockdep report to remind us that
grabbing i_mutex in the fault path is a no-no (write syscall may already
hold i_mutex while faulting user buffer).
We tried a completely different approach (see following patch) but that
proved inadequate: good enough for a rational workload, but not good
enough against trinity - which forks off so many mappings of the object
that contention on i_mmap_mutex while hole-puncher holds i_mutex builds
into serious starvation when concurrent faults force the puncher to fall
back to single-page unmap_mapping_range() searches of the i_mmap tree.
So return to the original umbrella approach, but keep away from i_mutex
this time. We really don't want to bloat every shmem inode with a new
mutex or completion, just to protect this unlikely case from trinity.
So extend the original with wait_queue_head on stack at the hole-punch
end, and wait_queue item on the stack at the fault end.
This involves further use of i_lock to guard against the races: lockdep
has been happy so far, and I see fs/inode.c:unlock_new_inode() holds
i_lock around wake_up_bit(), which is comparable to what we do here.
i_lock is more convenient, but we could switch to shmem's info->lock.
This issue has been tagged with CVE-2014-4171, which will require commit
f00cdc6df7d7 and this and the following patch to be backported: we
suggest to 3.1+, though in fact the trinity forkbomb effect might go
back as far as 2.6.16, when madvise(,,MADV_REMOVE) came in - or might
not, since much has changed, with i_mmap_mutex a spinlock before 3.0.
Anyone running trinity on 3.0 and earlier? I don't think we need care.
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lukas Czerner <lczerner@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit f00cdc6df7d7cfcabb5b740911e6788cb0802bdb upstream.
Trinity finds that mmap access to a hole while it's punched from shmem
can prevent the madvise(MADV_REMOVE) or fallocate(FALLOC_FL_PUNCH_HOLE)
from completing, until the reader chooses to stop; with the puncher's
hold on i_mutex locking out all other writers until it can complete.
It appears that the tmpfs fault path is too light in comparison with its
hole-punching path, lacking an i_data_sem to obstruct it; but we don't
want to slow down the common case.
Extend shmem_fallocate()'s existing range notification mechanism, so
shmem_fault() can refrain from faulting pages into the hole while it's
punched, waiting instead on i_mutex (when safe to sleep; or repeatedly
faulting when not).
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 391acf970d21219a2a5446282d3b20eace0c0d7a upstream.
When runing with the kernel(3.15-rc7+), the follow bug occurs:
[ 9969.258987] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:586
[ 9969.359906] in_atomic(): 1, irqs_disabled(): 0, pid: 160655, name: python
[ 9969.441175] INFO: lockdep is turned off.
[ 9969.488184] CPU: 26 PID: 160655 Comm: python Tainted: G A 3.15.0-rc7+ #85
[ 9969.581032] Hardware name: FUJITSU-SV PRIMEQUEST 1800E/SB, BIOS PRIMEQUEST 1000 Series BIOS Version 1.39 11/16/2012
[ 9969.706052] ffffffff81a20e60 ffff8803e941fbd0 ffffffff8162f523 ffff8803e941fd18
[ 9969.795323] ffff8803e941fbe0 ffffffff8109995a ffff8803e941fc58 ffffffff81633e6c
[ 9969.884710] ffffffff811ba5dc ffff880405c6b480 ffff88041fdd90a0 0000000000002000
[ 9969.974071] Call Trace:
[ 9970.003403] [<ffffffff8162f523>] dump_stack+0x4d/0x66
[ 9970.065074] [<ffffffff8109995a>] __might_sleep+0xfa/0x130
[ 9970.130743] [<ffffffff81633e6c>] mutex_lock_nested+0x3c/0x4f0
[ 9970.200638] [<ffffffff811ba5dc>] ? kmem_cache_alloc+0x1bc/0x210
[ 9970.272610] [<ffffffff81105807>] cpuset_mems_allowed+0x27/0x140
[ 9970.344584] [<ffffffff811b1303>] ? __mpol_dup+0x63/0x150
[ 9970.409282] [<ffffffff811b1385>] __mpol_dup+0xe5/0x150
[ 9970.471897] [<ffffffff811b1303>] ? __mpol_dup+0x63/0x150
[ 9970.536585] [<ffffffff81068c86>] ? copy_process.part.23+0x606/0x1d40
[ 9970.613763] [<ffffffff810bf28d>] ? trace_hardirqs_on+0xd/0x10
[ 9970.683660] [<ffffffff810ddddf>] ? monotonic_to_bootbased+0x2f/0x50
[ 9970.759795] [<ffffffff81068cf0>] copy_process.part.23+0x670/0x1d40
[ 9970.834885] [<ffffffff8106a598>] do_fork+0xd8/0x380
[ 9970.894375] [<ffffffff81110e4c>] ? __audit_syscall_entry+0x9c/0xf0
[ 9970.969470] [<ffffffff8106a8c6>] SyS_clone+0x16/0x20
[ 9971.030011] [<ffffffff81642009>] stub_clone+0x69/0x90
[ 9971.091573] [<ffffffff81641c29>] ? system_call_fastpath+0x16/0x1b
The cause is that cpuset_mems_allowed() try to take
mutex_lock(&callback_mutex) under the rcu_read_lock(which was hold in
__mpol_dup()). And in cpuset_mems_allowed(), the access to cpuset is
under rcu_read_lock, so in __mpol_dup, we can reduce the rcu_read_lock
protection region to protect the access to cpuset only in
current_cpuset_is_being_rebound(). So that we can avoid this bug.
This patch is a temporary solution that just addresses the bug
mentioned above, can not fix the long-standing issue about cpuset.mems
rebinding on fork():
"When the forker's task_struct is duplicated (which includes
->mems_allowed) and it races with an update to cpuset_being_rebound
in update_tasks_nodemask() then the task's mems_allowed doesn't get
updated. And the child task's mems_allowed can be wrong if the
cpuset's nodemask changes before the child has been added to the
cgroup's tasklist."
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit d05f0cdcbe6388723f1900c549b4850360545201 upstream.
In v2.6.34 commit 9d8cebd4bcd7 ("mm: fix mbind vma merge problem")
introduced vma merging to mbind(), but it should have also changed the
convention of passing start vma from queue_pages_range() (formerly
check_range()) to new_vma_page(): vma merging may have already freed
that structure, resulting in BUG at mm/mempolicy.c:1738 and probably
worse crashes.
Fixes: 9d8cebd4bcd7 ("mm: fix mbind vma merge problem")
Reported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- Adjust context
- Keep the same arguments to migrate_pages() except for private=start]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 082708072a4250f5c4dbc62065e7af93f5e45646 upstream.
Revert commit 0def08e3acc2 because check_range can't fail in
migrate_to_node with considering current usecases.
Quote from Johannes
: I think it makes sense to revert. Not because of the semantics, but I
: just don't see how check_range() could even fail for this callsite:
:
: 1. we pass mm->mmap->vm_start in there, so we should not fail due to
: find_vma()
:
: 2. we pass MPOL_MF_DISCONTIG_OK, so the discontig checks do not apply
: and so can not fail
:
: 3. we pass MPOL_MF_MOVE | MPOL_MF_MOVE_ALL, the page table loops will
: continue until addr == end, so we never fail with -EIO
And I added a new VM_BUG_ON for checking migrate_to_node's future usecase
which might pass to MPOL_MF_STRICT.
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 4a705fef986231a3e7a6b1a6d3c37025f021f49f upstream.
There's a race between fork() and hugepage migration, as a result we try
to "dereference" a swap entry as a normal pte, causing kernel panic.
The cause of the problem is that copy_hugetlb_page_range() can't handle
"swap entry" family (migration entry and hwpoisoned entry) so let's fix
it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 624483f3ea82598ab0f62f1bdb9177f531ab1892 upstream.
While working address sanitizer for kernel I've discovered
use-after-free bug in __put_anon_vma.
For the last anon_vma, anon_vma->root freed before child anon_vma.
Later in anon_vma_free(anon_vma) we are referencing to already freed
anon_vma->root to check rwsem.
This fixes it by freeing the child anon_vma before freeing
anon_vma->root.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 71abdc15adf8c702a1dd535f8e30df50758848d2 upstream.
When kswapd exits, it can end up taking locks that were previously held
by allocating tasks while they waited for reclaim. Lockdep currently
warns about this:
On Wed, May 28, 2014 at 06:06:34PM +0800, Gu Zheng wrote:
> inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-R} usage.
> kswapd2/1151 [HC0[0]:SC0[0]:HE1:SE1] takes:
> (&sig->group_rwsem){+++++?}, at: exit_signals+0x24/0x130
> {RECLAIM_FS-ON-W} state was registered at:
> mark_held_locks+0xb9/0x140
> lockdep_trace_alloc+0x7a/0xe0
> kmem_cache_alloc_trace+0x37/0x240
> flex_array_alloc+0x99/0x1a0
> cgroup_attach_task+0x63/0x430
> attach_task_by_pid+0x210/0x280
> cgroup_procs_write+0x16/0x20
> cgroup_file_write+0x120/0x2c0
> vfs_write+0xc0/0x1f0
> SyS_write+0x4c/0xa0
> tracesys+0xdd/0xe2
> irq event stamp: 49
> hardirqs last enabled at (49): _raw_spin_unlock_irqrestore+0x36/0x70
> hardirqs last disabled at (48): _raw_spin_lock_irqsave+0x2b/0xa0
> softirqs last enabled at (0): copy_process.part.24+0x627/0x15f0
> softirqs last disabled at (0): (null)
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&sig->group_rwsem);
> <Interrupt>
> lock(&sig->group_rwsem);
>
> *** DEADLOCK ***
>
> no locks held by kswapd2/1151.
>
> stack backtrace:
> CPU: 30 PID: 1151 Comm: kswapd2 Not tainted 3.10.39+ #4
> Call Trace:
> dump_stack+0x19/0x1b
> print_usage_bug+0x1f7/0x208
> mark_lock+0x21d/0x2a0
> __lock_acquire+0x52a/0xb60
> lock_acquire+0xa2/0x140
> down_read+0x51/0xa0
> exit_signals+0x24/0x130
> do_exit+0xb5/0xa50
> kthread+0xdb/0x100
> ret_from_fork+0x7c/0xb0
This is because the kswapd thread is still marked as a reclaimer at the
time of exit. But because it is exiting, nobody is actually waiting on
it to make reclaim progress anymore, and it's nothing but a regular
thread at this point. Be tidy and strip it of all its powers
(PF_MEMALLOC, PF_SWAPWRITE, PF_KSWAPD, and the lockdep reclaim state)
before returning from the thread function.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 7f39dda9d86fb4f4f17af0de170decf125726f8c upstream.
Trinity reports BUG:
sleeping function called from invalid context at kernel/locking/rwsem.c:47
in_atomic(): 0, irqs_disabled(): 0, pid: 5787, name: trinity-c27
__might_sleep < down_write < __put_anon_vma < page_get_anon_vma <
migrate_pages < compact_zone < compact_zone_order < try_to_compact_pages ..
Right, since conversion to mutex then rwsem, we should not put_anon_vma()
from inside an rcu_read_lock()ed section: fix the two places that did so.
And add might_sleep() to anon_vma_free(), as suggested by Peter Zijlstra.
Fixes: 88c22088bf23 ("mm: optimize page_lock_anon_vma() fast-path")
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 498c2280212327858e521e9d21345d4cc2637f54 upstream.
kmap_to_page returns the corresponding struct page for a virtual address
of an arbitrary mapping. This works by checking whether the address
falls in the pkmap region and using the pkmap page tables instead of the
linear mapping if appropriate.
Unfortunately, the bounds checking means that PKMAP_ADDR(LAST_PKMAP) is
incorrectly treated as a highmem address and we can end up walking off
the end of pkmap_page_table and subsequently passing junk to pte_page.
This patch fixes the bound check to stay within the pkmap tables.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 3e030ecc0fc7de10fd0da10c1c19939872a31717 upstream.
When a memory error happens on an in-use page or (free and in-use)
hugepage, the victim page is isolated with its refcount set to one.
When you try to unpoison it later, unpoison_memory() calls put_page()
for it twice in order to bring the page back to free page pool (buddy or
free hugepage list). However, if another memory error occurs on the
page which we are unpoisoning, memory_failure() returns without
releasing the refcount which was incremented in the same call at first,
which results in memory leak and unconsistent num_poisoned_pages
statistics. This patch fixes it.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: s/num_poisoned_pages/bad_mce_pages/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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hugepage
commit b985194c8c0a130ed155b71662e39f7eaea4876f upstream.
For handling a free hugepage in memory failure, the race will happen if
another thread hwpoisoned this hugepage concurrently. So we need to
check PageHWPoison instead of !PageHWPoison.
If hwpoison_filter(p) returns true or a race happens, then we need to
unlock_page(hpage).
Signed-off-by: Chen Yucong <slaoub@gmail.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: s/num_poisoned_pages/bad_mce_pages/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit d5c9fde3dae750889168807038243ff36431d276 upstream.
It is possible for "limit - setpoint + 1" to equal zero, after getting
truncated to a 32 bit variable, and resulting in a divide by zero error.
Using the fully 64 bit divide functions avoids this problem. It also
will cause pos_ratio_polynom() to return the correct value when
(setpoint - limit) exceeds 2^32.
Also uninline pos_ratio_polynom, at Andrew's request.
Signed-off-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
Adjust context - pos_ratio_polynom() is not a separate function]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit ed84825b785ceb932af7dd5aa08614801721320b upstream.
In bdi_position_ratio(), get difference (setpoint-dirty) right even when
negative. Both setpoint and dirty are unsigned long, the difference was
zero-padded thus wrongly sign-extended to s64. This issue affects all
32-bit architectures, does not affect 64-bit architectures where long
and s64 are equivalent.
In this function, dirty is between freerun and limit, the pseudo-float x
is between [-1,1], expected to be negative about half the time. With
zero-padding, instead of a small negative x we obtained a large positive
one so bdi_position_ratio() returned garbage.
Casting the difference to s64 also prevents overflow with left-shift;
though normally these numbers are small and I never observed a 32-bit
overflow there.
(This patch does not solve the PAE OOM issue.)
Paul Szabo psz@maths.usyd.edu.au http://www.maths.usyd.edu.au/u/psz/
School of Mathematics and Statistics University of Sydney Australia
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Paul Szabo <psz@maths.usyd.edu.au>
Reference: http://bugs.debian.org/695182
Signed-off-by: Paul Szabo <psz@maths.usyd.edu.au>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 1b17844b29ae042576bea588164f2f1e9590a8bc upstream.
fixup_user_fault() is used by the futex code when the direct user access
fails, and the futex code wants it to either map in the page in a usable
form or return an error. It relied on handle_mm_fault() to map the
page, and correctly checked the error return from that, but while that
does map the page, it doesn't actually guarantee that the page will be
mapped with sufficient permissions to be then accessed.
So do the appropriate tests of the vma access rights by hand.
[ Side note: arguably handle_mm_fault() could just do that itself, but
we have traditionally done it in the caller, because some callers -
notably get_user_pages() - have been able to access pages even when
they are mapped with PROT_NONE. Maybe we should re-visit that design
decision, but in the meantime this is the minimal patch. ]
Found by Dave Jones running his trinity tool.
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 7848a4bf51b34f41fcc9bd77e837126d99ae84e3 upstream.
soft lockup in freeing gigantic hugepage fixed in commit 55f67141a892 "mm:
hugetlb: fix softlockup when a large number of hugepages are freed." can
happen in return_unused_surplus_pages(), so let's fix it.
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 55f67141a8927b2be3e51840da37b8a2320143ed upstream.
When I decrease the value of nr_hugepage in procfs a lot, softlockup
happens. It is because there is no chance of context switch during this
process.
On the other hand, when I allocate a large number of hugepages, there is
some chance of context switch. Hence softlockup doesn't happen during
this process. So it's necessary to add the context switch in the
freeing process as same as allocating process to avoid softlockup.
When I freed 12 TB hugapages with kernel-2.6.32-358.el6, the freeing
process occupied a CPU over 150 seconds and following softlockup message
appeared twice or more.
$ echo 6000000 > /proc/sys/vm/nr_hugepages
$ cat /proc/sys/vm/nr_hugepages
6000000
$ grep ^Huge /proc/meminfo
HugePages_Total: 6000000
HugePages_Free: 6000000
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
$ echo 0 > /proc/sys/vm/nr_hugepages
BUG: soft lockup - CPU#16 stuck for 67s! [sh:12883] ...
Pid: 12883, comm: sh Not tainted 2.6.32-358.el6.x86_64 #1
Call Trace:
free_pool_huge_page+0xb8/0xd0
set_max_huge_pages+0x128/0x190
hugetlb_sysctl_handler_common+0x113/0x140
hugetlb_sysctl_handler+0x1e/0x20
proc_sys_call_handler+0x97/0xd0
proc_sys_write+0x14/0x20
vfs_write+0xb8/0x1a0
sys_write+0x51/0x90
__audit_syscall_exit+0x265/0x290
system_call_fastpath+0x16/0x1b
I have not confirmed this problem with upstream kernels because I am not
able to prepare the machine equipped with 12TB memory now. However I
confirmed that the amount of decreasing hugepages was directly
proportional to the amount of required time.
I measured required times on a smaller machine. It showed 130-145
hugepages decreased in a millisecond.
Amount of decreasing Required time Decreasing rate
hugepages (msec) (pages/msec)
------------------------------------------------------------
10,000 pages == 20GB 70 - 74 135-142
30,000 pages == 60GB 208 - 229 131-144
It means decrement of 6TB hugepages will trigger softlockup with the
default threshold 20sec, in this decreasing rate.
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 57e68e9cd65b4b8eb4045a1e0d0746458502554c upstream.
A BUG_ON(!PageLocked) was triggered in mlock_vma_page() by Sasha Levin
fuzzing with trinity. The call site try_to_unmap_cluster() does not lock
the pages other than its check_page parameter (which is already locked).
The BUG_ON in mlock_vma_page() is not documented and its purpose is
somewhat unclear, but apparently it serializes against page migration,
which could otherwise fail to transfer the PG_mlocked flag. This would
not be fatal, as the page would be eventually encountered again, but
NR_MLOCK accounting would become distorted nevertheless. This patch adds
a comment to the BUG_ON in mlock_vma_page() and munlock_vma_page() to that
effect.
The call site try_to_unmap_cluster() is fixed so that for page !=
check_page, trylock_page() is attempted (to avoid possible deadlocks as we
already have check_page locked) and mlock_vma_page() is performed only
upon success. If the page lock cannot be obtained, the page is left
without PG_mlocked, which is again not a problem in the whole unevictable
memory design.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 98398c32f6687ee1e1f3ae084effb4b75adb0747 upstream.
In __page_check_address(), if address's pud is not present,
huge_pte_offset() will return NULL, we should check the return value.
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: qiuxishi <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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spin_lock_irq()
commit a85d9df1ea1d23682a0ed1e100e6965006595d06 upstream.
During aio stress test, we observed the following lockdep warning. This
mean AIO+numa_balancing is currently deadlockable.
The problem is, aio_migratepage disable interrupt, but
__set_page_dirty_nobuffers unintentionally enable it again.
Generally, all helper function should use spin_lock_irqsave() instead of
spin_lock_irq() because they don't know caller at all.
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&ctx->completion_lock)->rlock);
<Interrupt>
lock(&(&ctx->completion_lock)->rlock);
*** DEADLOCK ***
dump_stack+0x19/0x1b
print_usage_bug+0x1f7/0x208
mark_lock+0x21d/0x2a0
mark_held_locks+0xb9/0x140
trace_hardirqs_on_caller+0x105/0x1d0
trace_hardirqs_on+0xd/0x10
_raw_spin_unlock_irq+0x2c/0x50
__set_page_dirty_nobuffers+0x8c/0xf0
migrate_page_copy+0x434/0x540
aio_migratepage+0xb1/0x140
move_to_new_page+0x7d/0x230
migrate_pages+0x5e5/0x700
migrate_misplaced_page+0xbc/0xf0
do_numa_page+0x102/0x190
handle_pte_fault+0x241/0x970
handle_mm_fault+0x265/0x370
__do_page_fault+0x172/0x5a0
do_page_fault+0x1a/0x70
page_fault+0x28/0x30
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit f893ab41e4dae2fe8991faf5d86d029068d1ef3a upstream.
swapoff clear swap_info's SWP_USED flag prematurely and free its
resources after that. A concurrent swapon will reuse this swap_info
while its previous resources are not cleared completely.
These late freed resources are:
- p->percpu_cluster
- swap_cgroup_ctrl[type]
- block_device setting
- inode->i_flags &= ~S_SWAPFILE
This patch clears the SWP_USED flag after all its resources are freed,
so that swapon can reuse this swap_info by alloc_swap_info() safely.
[akpm@linux-foundation.org: tidy up code comment]
Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 778c14affaf94a9e4953179d3e13a544ccce7707 upstream.
A 3% of system memory bonus is sometimes too excessive in comparison to
other processes.
With commit a63d83f427fb ("oom: badness heuristic rewrite"), the OOM
killer tries to avoid killing privileged tasks by subtracting 3% of
overall memory (system or cgroup) from their per-task consumption. But
as a result, all root tasks that consume less than 3% of overall memory
are considered equal, and so it only takes 33+ privileged tasks pushing
the system out of memory for the OOM killer to do something stupid and
kill dhclient or other root-owned processes. For example, on a 32G
machine it can't tell the difference between the 1M agetty and the 10G
fork bomb member.
The changelog describes this 3% boost as the equivalent to the global
overcommit limit being 3% higher for privileged tasks, but this is not
the same as discounting 3% of overall memory from _every privileged task
individually_ during OOM selection.
Replace the 3% of system memory bonus with a 3% of current memory usage
bonus.
By giving root tasks a bonus that is proportional to their actual size,
they remain comparable even when relatively small. In the example
above, the OOM killer will discount the 1M agetty's 256 badness points
down to 179, and the 10G fork bomb's 262144 points down to 183500 points
and make the right choice, instead of discounting both to 0 and killing
agetty because it's first in the task list.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: existing code changes 'points' directly rather
than using 'adj' variable]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 8afb1474db4701d1ab80cd8251137a3260e6913e upstream.
/sys/kernel/slab/:t-0000048 # cat cpu_slabs
231 N0=16 N1=215
/sys/kernel/slab/:t-0000048 # cat slabs
145 N0=36 N1=109
See, the number of slabs is smaller than that of cpu slabs.
The bug was introduced by commit 49e2258586b423684f03c278149ab46d8f8b6700
("slub: per cpu cache for partial pages").
We should use page->pages instead of page->pobjects when calculating
the number of cpu partial slabs. This also fixes the mapping of slabs
and nodes.
As there's no variable storing the number of total/active objects in
cpu partial slabs, and we don't have user interfaces requiring those
statistics, I just add WARN_ON for those cases.
Acked-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 27c73ae759774e63313c1fbfeb17ba076cea64c5 upstream.
Commit 7cb2ef56e6a8 ("mm: fix aio performance regression for database
caused by THP") can cause dereference of a dangling pointer if
split_huge_page runs during PageHuge() if there are updates to the
tail_page->private field.
Also it is repeating compound_head twice for hugetlbfs and it is running
compound_head+compound_trans_head for THP when a single one is needed in
both cases.
The new code within the PageSlab() check doesn't need to verify that the
THP page size is never bigger than the smallest hugetlbfs page size, to
avoid memory corruption.
A longstanding theoretical race condition was found while fixing the
above (see the change right after the skip_unlock label, that is
relevant for the compound_lock path too).
By re-establishing the _mapcount tail refcounting for all compound
pages, this also fixes the below problem:
echo 0 >/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
BUG: Bad page state in process bash pfn:59a01
page:ffffea000139b038 count:0 mapcount:10 mapping: (null) index:0x0
page flags: 0x1c00000000008000(tail)
Modules linked in:
CPU: 6 PID: 2018 Comm: bash Not tainted 3.12.0+ #25
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x55/0x76
bad_page+0xd5/0x130
free_pages_prepare+0x213/0x280
__free_pages+0x36/0x80
update_and_free_page+0xc1/0xd0
free_pool_huge_page+0xc2/0xe0
set_max_huge_pages.part.58+0x14c/0x220
nr_hugepages_store_common.isra.60+0xd0/0xf0
nr_hugepages_store+0x13/0x20
kobj_attr_store+0xf/0x20
sysfs_write_file+0x189/0x1e0
vfs_write+0xc5/0x1f0
SyS_write+0x55/0xb0
system_call_fastpath+0x16/0x1b
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Khalid Aziz: Backported to 3.4]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 7cb2ef56e6a8b7b368b2e883a0a47d02fed66911 upstream.
I am working with a tool that simulates oracle database I/O workload.
This tool (orion to be specific -
<http://docs.oracle.com/cd/E11882_01/server.112/e16638/iodesign.htm#autoId24>)
allocates hugetlbfs pages using shmget() with SHM_HUGETLB flag. It then
does aio into these pages from flash disks using various common block
sizes used by database. I am looking at performance with two of the most
common block sizes - 1M and 64K. aio performance with these two block
sizes plunged after Transparent HugePages was introduced in the kernel.
Here are performance numbers:
pre-THP 2.6.39 3.11-rc5
1M read 8384 MB/s 5629 MB/s 6501 MB/s
64K read 7867 MB/s 4576 MB/s 4251 MB/s
I have narrowed the performance impact down to the overheads introduced by
THP in __get_page_tail() and put_compound_page() routines. perf top shows
>40% of cycles being spent in these two routines. Every time direct I/O
to hugetlbfs pages starts, kernel calls get_page() to grab a reference to
the pages and calls put_page() when I/O completes to put the reference
away. THP introduced significant amount of locking overhead to get_page()
and put_page() when dealing with compound pages because hugepages can be
split underneath get_page() and put_page(). It added this overhead
irrespective of whether it is dealing with hugetlbfs pages or transparent
hugepages. This resulted in 20%-45% drop in aio performance when using
hugetlbfs pages.
Since hugetlbfs pages can not be split, there is no reason to go through
all the locking overhead for these pages from what I can see. I added
code to __get_page_tail() and put_compound_page() to bypass all the
locking code when working with hugetlbfs pages. This improved performance
significantly. Performance numbers with this patch:
pre-THP 3.11-rc5 3.11-rc5 + Patch
1M read 8384 MB/s 6501 MB/s 8371 MB/s
64K read 7867 MB/s 4251 MB/s 6510 MB/s
Performance with 64K read is still lower than what it was before THP, but
still a 53% improvement. It does mean there is more work to be done but I
will take a 53% improvement for now.
Please take a look at the following patch and let me know if it looks
reasonable.
[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit 2afc745f3e3079ab16c826be4860da2529054dd2 upstream.
This patch fixes the problem that get_unmapped_area() can return illegal
address and result in failing mmap(2) etc.
In case that the address higher than PAGE_SIZE is set to
/proc/sys/vm/mmap_min_addr, the address lower than mmap_min_addr can be
returned by get_unmapped_area(), even if you do not pass any virtual
address hint (i.e. the second argument).
This is because the current get_unmapped_area() code does not take into
account mmap_min_addr.
This leads to two actual problems as follows:
1. mmap(2) can fail with EPERM on the process without CAP_SYS_RAWIO,
although any illegal parameter is not passed.
2. The bottom-up search path after the top-down search might not work in
arch_get_unmapped_area_topdown().
Note: The first and third chunk of my patch, which changes "len" check,
are for more precise check using mmap_min_addr, and not for solving the
above problem.
[How to reproduce]
--- test.c -------------------------------------------------
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/errno.h>
int main(int argc, char *argv[])
{
void *ret = NULL, *last_map;
size_t pagesize = sysconf(_SC_PAGESIZE);
do {
last_map = ret;
ret = mmap(0, pagesize, PROT_NONE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
// printf("ret=%p\n", ret);
} while (ret != MAP_FAILED);
if (errno != ENOMEM) {
printf("ERR: unexpected errno: %d (last map=%p)\n",
errno, last_map);
}
return 0;
}
---------------------------------------------------------------
$ gcc -m32 -o test test.c
$ sudo sysctl -w vm.mmap_min_addr=65536
vm.mmap_min_addr = 65536
$ ./test (run as non-priviledge user)
ERR: unexpected errno: 1 (last map=0x10000)
Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
As we do not have vm_unmapped_area(), make arch_get_unmapped_area_topdown()
calculate the lower limit for the new area's end address and then compare
addresses with this instead of with len. In the process, fix an off-by-one
error which could result in returning 0 if mm->mmap_base == len.]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 upstream.
After a successful hugetlb page migration by soft offline, the source
page will either be freed into hugepage_freelists or buddy(over-commit
page). If page is in buddy, page_hstate(page) will be NULL. It will
hit a NULL pointer dereference in dequeue_hwpoisoned_huge_page().
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0
PGD c23762067 PUD c24be2067 PMD 0
Oops: 0000 [#1] SMP
So check PageHuge(page) after call migrate_pages() successfully.
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[wujg: backport to 3.4:
- adjust context
- s/num_poisoned_pages/mce_bad_pages/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit 4b59e6c4730978679b414a8da61514a2518da512 upstream.
On large systems with a lot of memory, walking all RAM to determine page
types may take a half second or even more.
In non-blockable contexts, the page allocator will emit a page allocation
failure warning unless __GFP_NOWARN is specified. In such contexts, irqs
are typically disabled and such a lengthy delay may even result in NMI
watchdog timeouts.
To fix this, suppress the page walk in such contexts when printing the
page allocation failure warning.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit 2bff24a3707093c435ab3241c47dcdb5f16e432b upstream.
A memory cgroup with (1) multiple threshold notifications and (2) at least
one threshold >=2G was not reliable. Specifically the notifications would
either not fire or would not fire in the proper order.
The __mem_cgroup_threshold() signaling logic depends on keeping 64 bit
thresholds in sorted order. mem_cgroup_usage_register_event() sorts them
with compare_thresholds(), which returns the difference of two 64 bit
thresholds as an int. If the difference is positive but has bit[31] set,
then sort() treats the difference as negative and breaks sort order.
This fix compares the two arbitrary 64 bit thresholds returning the
classic -1, 0, 1 result.
The test below sets two notifications (at 0x1000 and 0x81001000):
cd /sys/fs/cgroup/memory
mkdir x
for x in 4096 2164264960; do
cgroup_event_listener x/memory.usage_in_bytes $x | sed "s/^/$x listener:/" &
done
echo $$ > x/cgroup.procs
anon_leaker 500M
v3.11-rc7 fails to signal the 4096 event listener:
Leaking...
Done leaking pages.
Patched v3.11-rc7 properly notifies:
Leaking...
4096 listener:2013:8:31:14:13:36
Done leaking pages.
The fixed bug is old. It appears to date back to the introduction of
memcg threshold notifications in v2.6.34-rc1-116-g2e72b6347c94 "memcg:
implement memory thresholds"
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit a8f531ebc33052642b4bd7b812eedf397108ce64 upstream.
In collapse_huge_page() there is a race window between releasing the
mmap_sem read lock and taking the mmap_sem write lock, so find_vma() may
return NULL. So check the return value to avoid NULL pointer dereference.
collapse_huge_page
khugepaged_alloc_page
up_read(&mm->mmap_sem)
down_write(&mm->mmap_sem)
vma = find_vma(mm, address)
Signed-off-by: Libin <huawei.libin@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit d74c6d514fe314b8bdab58b487b25992291577ec upstream.
__bio_for_each_segment() iterates bvecs from the specified index
instead of bio->bv_idx. Currently, the only usage is to walk all the
bvecs after the bio has been advanced by specifying 0 index.
For immutable bvecs, we need to split these apart;
bio_for_each_segment() is going to have a different implementation.
This will also help document the intent of code that's using it -
bio_for_each_segment_all() is only legal to use for code that owns the
bio.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Neil Brown <neilb@suse.de>
CC: Boaz Harrosh <bharrosh@panasas.com>
[bwh: Backported to 3.2: drop inapplicable change to drivers/block/rbd.c.
This is a prerequisite for commit 35dc248383bb 'sg: Fix user memory
corruption when SG_IO is interrupted by a signal']
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
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commit 3c0b9de6d37a481673e81001c57ca0e410c72346 upstream.
I think we could just move the full vm_iomap_memory() function into
util.h or similar, but I didn't get any reply from anybody actually
using nommu even to this trivial patch, so I'm not going to touch it any
more than required.
Here's the fairly minimal stub to make the nommu case at least
potentially work. It doesn't seem like anybody cares, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit cea27eb2a202959783f81254c48c250ddd80e129 upstream.
The logic for the memory-remove code fails to correctly account the
Total High Memory when a memory block which contains High Memory is
offlined as shown in the example below. The following patch fixes it.
Before logic memory remove:
MemTotal: 7603740 kB
MemFree: 6329612 kB
Buffers: 94352 kB
Cached: 872008 kB
SwapCached: 0 kB
Active: 626932 kB
Inactive: 519216 kB
Active(anon): 180776 kB
Inactive(anon): 222944 kB
Active(file): 446156 kB
Inactive(file): 296272 kB
Unevictable: 0 kB
Mlocked: 0 kB
HighTotal: 7294672 kB
HighFree: 5704696 kB
LowTotal: 309068 kB
LowFree: 624916 kB
After logic memory remove:
MemTotal: 7079452 kB
MemFree: 5805976 kB
Buffers: 94372 kB
Cached: 872000 kB
SwapCached: 0 kB
Active: 626936 kB
Inactive: 519236 kB
Active(anon): 180780 kB
Inactive(anon): 222944 kB
Active(file): 446156 kB
Inactive(file): 296292 kB
Unevictable: 0 kB
Mlocked: 0 kB
HighTotal: 7294672 kB
HighFree: 5181024 kB
LowTotal: 4294752076 kB
LowFree: 624952 kB
[mhocko@suse.cz: fix CONFIG_HIGHMEM=n build]
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Backported for 3.4-stable. Adjusted context.]
Signed-off-by: Zhouping Liu <zliu@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit 13d60f4b6ab5b702dc8d2ee20999f98a93728aec upstream.
The futex_keys of process shared futexes are generated from the page
offset, the mapping host and the mapping index of the futex user space
address. This should result in an unique identifier for each futex.
Though this is not true when futexes are located in different subpages
of an hugepage. The reason is, that the mapping index for all those
futexes evaluates to the index of the base page of the hugetlbfs
mapping. So a futex at offset 0 of the hugepage mapping and another
one at offset PAGE_SIZE of the same hugepage mapping have identical
futex_keys. This happens because the futex code blindly uses
page->index.
Steps to reproduce the bug:
1. Map a file from hugetlbfs. Initialize pthread_mutex1 at offset 0
and pthread_mutex2 at offset PAGE_SIZE of the hugetlbfs
mapping.
The mutexes must be initialized as PTHREAD_PROCESS_SHARED because
PTHREAD_PROCESS_PRIVATE mutexes are not affected by this issue as
their keys solely depend on the user space address.
2. Lock mutex1 and mutex2
3. Create thread1 and in the thread function lock mutex1, which
results in thread1 blocking on the locked mutex1.
4. Create thread2 and in the thread function lock mutex2, which
results in thread2 blocking on the locked mutex2.
5. Unlock mutex2. Despite the fact that mutex2 got unlocked, thread2
still blocks on mutex2 because the futex_key points to mutex1.
To solve this issue we need to take the normal page index of the page
which contains the futex into account, if the futex is in an hugetlbfs
mapping. In other words, we calculate the normal page mapping index of
the subpage in the hugetlbfs mapping.
Mappings which are not based on hugetlbfs are not affected and still
use page->index.
Thanks to Mel Gorman who provided a patch for adding proper evaluation
functions to the hugetlbfs code to avoid exposing hugetlbfs specific
details to the futex code.
[ tglx: Massaged changelog ]
Signed-off-by: Zhang Yi <zhang.yi20@zte.com.cn>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>
Tested-by: Ma Chenggong <ma.chenggong@zte.com.cn>
Reviewed-by: 'Mel Gorman' <mgorman@suse.de>
Acked-by: 'Darren Hart' <dvhart@linux.intel.com>
Cc: 'Peter Zijlstra' <peterz@infradead.org>
Link: http://lkml.kernel.org/r/000101ce71a6%24a83c5880%24f8b50980%24@com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit 30dad30922ccc733cfdbfe232090cf674dc374dc upstream.
When we have a page fault for the address which is backed by a hugepage
under migration, the kernel can't wait correctly and do busy looping on
hugepage fault until the migration finishes. As a result, users who try
to kick hugepage migration (via soft offlining, for example) occasionally
experience long delay or soft lockup.
This is because pte_offset_map_lock() can't get a correct migration entry
or a correct page table lock for hugepage. This patch introduces
migration_entry_wait_huge() to solve this.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
discard I/O completion
commit cbab0e4eec299e9059199ebe6daf48730be46d2b upstream.
read_swap_cache_async() can race against get_swap_page(), and stumble
across a SWAP_HAS_CACHE entry in the swap map whose page wasn't brought
into the swapcache yet.
This transient swap_map state is expected to be transitory, but the
actual placement of discard at scan_swap_map() inserts a wait for I/O
completion thus making the thread at read_swap_cache_async() to loop
around its -EEXIST case, while the other end at get_swap_page() is
scheduled away at scan_swap_map(). This can leave the system deadlocked
if the I/O completion happens to be waiting on the CPU waitqueue where
read_swap_cache_async() is busy looping and !CONFIG_PREEMPT.
This patch introduces a cond_resched() call to make the aforementioned
read_swap_cache_async() busy loop condition to bail out when necessary,
thus avoiding the subtle race window.
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit a9ff785e4437c83d2179161e012f5bdfbd6381f0 upstream.
A panic can be caused by simply cat'ing /proc/<pid>/smaps while an
application has a VM_PFNMAP range. It happened in-house when a
benchmarker was trying to decipher the memory layout of his program.
/proc/<pid>/smaps and similar walks through a user page table should not
be looking at VM_PFNMAP areas.
Certain tests in walk_page_range() (specifically split_huge_page_pmd())
assume that all the mapped PFN's are backed with page structures. And
this is not usually true for VM_PFNMAP areas. This can result in panics
on kernel page faults when attempting to address those page structures.
There are a half dozen callers of walk_page_range() that walk through a
task's entire page table (as N. Horiguchi pointed out). So rather than
change all of them, this patch changes just walk_page_range() to ignore
VM_PFNMAP areas.
The logic of hugetlb_vma() is moved back into walk_page_range(), as we
want to test any vma in the range.
VM_PFNMAP areas are used by:
- graphics memory manager gpu/drm/drm_gem.c
- global reference unit sgi-gru/grufile.c
- sgi special memory char/mspec.c
- and probably several out-of-tree modules
[akpm@linux-foundation.org: remove now-unused hugetlb_vma() stub]
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit 7c3425123ddfdc5f48e7913ff59d908789712b18 upstream.
We should not use set_pmd_at to update pmd_t with pgtable_t pointer.
set_pmd_at is used to set pmd with huge pte entries and architectures
like ppc64, clear few flags from the pte when saving a new entry.
Without this change we observe bad pte errors like below on ppc64 with
THP enabled.
BUG: Bad page map in process ld mm=0xc000001ee39f4780 pte:7fc3f37848000001 pmd:c000001ec0000000
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit c2cc499c5bcf9040a738f49e8051b42078205748 upstream.
Page 'new' during MIGRATION can't be flushed with flush_cache_page().
Using flush_cache_page(vma, addr, pfn) is justified only if the page is
already placed in process page table, and that is done right after
flush_cache_page(). But without it the arch function has no knowledge
of process PTE and does nothing.
Besides that, flush_cache_page() flushes an application cache page, but
the kernel has a different page virtual address and dirtied it.
Replace it with flush_dcache_page(new) which is the proper usage.
The old page is flushed in try_to_unmap_one() before migration.
This bug takes place in Sead3 board with M14Kc MIPS CPU without cache
aliasing (but Harvard arch - separate I and D cache) in tight memory
environment (128MB) each 1-3days on SOAK test. It fails in cc1 during
kernel build (SIGILL, SIGBUS, SIGSEG) if CONFIG_COMPACTION is switched
ON.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Leonid Yegoshin <yegoshin@mips.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit d34883d4e35c0a994e91dd847a82b4c9e0c31d83 upstream.
Commit 751efd8610d3 ("mmu_notifier_unregister NULL Pointer deref and
multiple ->release()") breaks the fix 3ad3d901bbcf ("mm: mmu_notifier:
fix freed page still mapped in secondary MMU").
Since hlist_for_each_entry_rcu() is changed now, we can not revert that
patch directly, so this patch reverts the commit and simply fix the bug
spotted by that patch
This bug spotted by commit 751efd8610d3 is:
There is a race condition between mmu_notifier_unregister() and
__mmu_notifier_release().
Assume two tasks, one calling mmu_notifier_unregister() as a result
of a filp_close() ->flush() callout (task A), and the other calling
mmu_notifier_release() from an mmput() (task B).
A B
t1 srcu_read_lock()
t2 if (!hlist_unhashed())
t3 srcu_read_unlock()
t4 srcu_read_lock()
t5 hlist_del_init_rcu()
t6 synchronize_srcu()
t7 srcu_read_unlock()
t8 hlist_del_rcu() <--- NULL pointer deref.
This can be fixed by using hlist_del_init_rcu instead of hlist_del_rcu.
The another issue spotted in the commit is "multiple ->release()
callouts", we needn't care it too much because it is really rare (e.g,
can not happen on kvm since mmu-notify is unregistered after
exit_mmap()) and the later call of multiple ->release should be fast
since all the pages have already been released by the first call.
Anyway, this issue should be fixed in a separate patch.
-stable suggestions: Any version that has commit 751efd8610d3 need to be
backported. I find the oldest version has this commit is 3.0-stable.
[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Tested-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: hlist_for_each_entry_rcu() still requires the
struct hlist_node pointer]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
|
|
commit b4cbb197c7e7a68dbad0d491242e3ca67420c13e upstream.
Various drivers end up replicating the code to mmap() their memory
buffers into user space, and our core memory remapping function may be
very flexible but it is unnecessarily complicated for the common cases
to use.
Our internal VM uses pfn's ("page frame numbers") which simplifies
things for the VM, and allows us to pass physical addresses around in a
denser and more efficient format than passing a "phys_addr_t" around,
and having to shift it up and down by the page size. But it just means
that drivers end up doing that shifting instead at the interface level.
It also means that drivers end up mucking around with internal VM things
like the vma details (vm_pgoff, vm_start/end) way more than they really
need to.
So this just exports a function to map a certain physical memory range
into user space (using a phys_addr_t based interface that is much more
natural for a driver) and hides all the complexity from the driver.
Some drivers will still end up tweaking the vm_page_prot details for
things like prefetching or cacheability etc, but that's actually
relevant to the driver, rather than caring about what the page offset of
the mapping is into the particular IO memory region.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 2f800fbd777b792de54187088df19a7df0251254 upstream.
De-account the accumulative dirty counters on page redirty.
Page redirties (very common in ext4) will introduce mismatch between
counters (a) and (b)
a) NR_DIRTIED, BDI_DIRTIED, tsk->nr_dirtied
b) NR_WRITTEN, BDI_WRITTEN
This will introduce systematic errors in balanced_rate and result in
dirty page position errors (ie. the dirty pages are no longer balanced
around the global/bdi setpoints).
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 9cc3a5bd40067b9a0fbd49199d0780463fc2140f upstream.
With applying the previous patch "hugetlbfs: stop setting VM_DONTDUMP in
initializing vma(VM_HUGETLB)" to reenable hugepage coredump, if a memory
error happens on a hugepage and the affected processes try to access the
error hugepage, we hit VM_BUG_ON(atomic_read(&page->_count) <= 0) in
get_page().
The reason for this bug is that coredump-related code doesn't recognise
"hugepage hwpoison entry" with which a pmd entry is replaced when a memory
error occurs on a hugepage.
In other words, physical address information is stored in different bit
layout between hugepage hwpoison entry and pmd entry, so
follow_hugetlb_page() which is called in get_dump_page() returns a wrong
page from a given address.
The expected behavior is like this:
absent is_swap_pte FOLL_DUMP Expected behavior
-------------------------------------------------------------------
true false false hugetlb_fault
false true false hugetlb_fault
false false false return page
true false true skip page (to avoid allocation)
false true true hugetlb_fault
false false true return page
With this patch, we can call hugetlb_fault() and take proper actions (we
wait for migration entries, fail with VM_FAULT_HWPOISON_LARGE for
hwpoisoned entries,) and as the result we can dump all hugepages except
for hwpoisoned ones.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit b6a9b7f6b1f21735a7456d534dc0e68e61359d2c upstream.
find_vma() can be called by multiple threads with read lock
held on mm->mmap_sem and any of them can update mm->mmap_cache.
Prevent compiler from re-fetching mm->mmap_cache, because other
readers could update it in the meantime:
thread 1 thread 2
|
find_vma() | find_vma()
struct vm_area_struct *vma = NULL; |
vma = mm->mmap_cache; |
if (!(vma && vma->vm_end > addr |
&& vma->vm_start <= addr)) { |
| mm->mmap_cache = vma;
return vma; |
^^ compiler may optimize this |
local variable out and re-read |
mm->mmap_cache |
This issue can be reproduced with gcc-4.8.0-1 on s390x by running
mallocstress testcase from LTP, which triggers:
kernel BUG at mm/rmap.c:1088!
Call Trace:
([<000003d100c57000>] 0x3d100c57000)
[<000000000023a1c0>] do_wp_page+0x2fc/0xa88
[<000000000023baae>] handle_pte_fault+0x41a/0xac8
[<000000000023d832>] handle_mm_fault+0x17a/0x268
[<000000000060507a>] do_protection_exception+0x1e2/0x394
[<0000000000603a04>] pgm_check_handler+0x138/0x13c
[<000003fffcf1f07a>] 0x3fffcf1f07a
Last Breaking-Event-Address:
[<000000000024755e>] page_add_new_anon_rmap+0xc2/0x168
Thanks to Jakub Jelinek for his insight on gcc and helping to
track this down.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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accouting
commit d00285884c0892bb1310df96bce6056e9ce9b9d9 upstream.
hugetlb_total_pages is used for overcommit calculations but the current
implementation considers only the default hugetlb page size (which is
either the first defined hugepage size or the one specified by
default_hugepagesz kernel boot parameter).
If the system is configured for more than one hugepage size, which is
possible since commit a137e1cc6d6e ("hugetlbfs: per mount huge page
sizes") then the overcommit estimation done by __vm_enough_memory()
(resp. shown by meminfo_proc_show) is not precise - there is an
impression of more available/allowed memory. This can lead to an
unexpected ENOMEM/EFAULT resp. SIGSEGV when memory is accounted.
Testcase:
boot: hugepagesz=1G hugepages=1
the default overcommit ratio is 50
before patch:
egrep 'CommitLimit' /proc/meminfo
CommitLimit: 55434168 kB
after patch:
egrep 'CommitLimit' /proc/meminfo
CommitLimit: 54909880 kB
[akpm@linux-foundation.org: coding-style tweak]
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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