linux-toradex.git, branch v3.12.36 Linux kernel for Apalis and Colibri modules Linux 3.12.36 2015-01-13T07:47:50+00:00 Jiri Slaby jslaby@suse.cz 2015-01-08T11:52:02+00:00 f6101957e6e019e69b62e20d1f59c082068c9ca7 






thp: close race between split and zap huge pages
2015-01-13T07:47:49+00:00

Kirill A. Shutemov
kirill.shutemov@linux.intel.com

2014-04-18T22:07:25+00:00

198717b635ef0d51525f7b2c8282a05a00a42c51

commit b5a8cad376eebbd8598642697e92a27983aee802 upstream.

[stable 3.12 note]
This commit was supposed to fix a completely other issue. But in 3.12,
with commit f72e7dcdd25229446b102e587ef2f826f76bff28 (mm: let
mm_find_pmd fix buggy race with THP fault), we need this commit as
well (it fixes the issue as a by-product). Hugh Dickins writes:
<== citation starts here>
Fine for this to go in, but there is one catch, which I discovered
when backporting to v3.11: it needed one more hunk.  I haven't checked
your base tree, but if this applies then I believe you need it - most
of the time no problem, but it can case page migration to fail to find
a migration entry it inserted earlier, then BUG_ON(!PageLocked(p)) in
migration_entry_to_page() soon after.  Here's what I wrote back then:

Note on rebase to v3.11: added a hunk to replace the use of
mm_find_pmd() in page_check_address_pmd().  This call had been
similarly replaced by the time of my v3.16 commit, in Kirill
Shutemov's v3.15 b5a8cad376ee ("thp: close race between split and zap
huge pages"): which we do not need as such, since it's fixing v3.13
117b0791ac42 ("mm, thp: move ptl taking inside
page_check_address_pmd()"), from a split page-table-lock series we are
not backporting.  But without this additional hunk, rmap sometimes
broke when the new semantic for mm_find_pmd() was used here.
<== end of citation>

But instead of appending hunks to commits, I am taking a full,
backported version of commit b5a8cad376ee with this note prepended.

So the changelog of b5a8cad376ee is left below, but does not apply to
3.12 yet.
[=== stable 3.12 note ends here]

Sasha Levin has reported two THP BUGs[1][2].  I believe both of them
have the same root cause.  Let's look to them one by one.

The first bug[1] is "kernel BUG at mm/huge_memory.c:1829!".  It's
BUG_ON(mapcount != page_mapcount(page)) in __split_huge_page().  From my
testing I see that page_mapcount() is higher than mapcount here.

I think it happens due to race between zap_huge_pmd() and
page_check_address_pmd().  page_check_address_pmd() misses PMD which is
under zap:

	CPU0						CPU1
						zap_huge_pmd()
						  pmdp_get_and_clear()
__split_huge_page()
  anon_vma_interval_tree_foreach()
    __split_huge_page_splitting()
      page_check_address_pmd()
        mm_find_pmd()
	  /*
	   * We check if PMD present without taking ptl: no
	   * serialization against zap_huge_pmd(). We miss this PMD,
	   * it's not accounted to 'mapcount' in __split_huge_page().
	   */
	  pmd_present(pmd) == 0

  BUG_ON(mapcount != page_mapcount(page)) // CRASH!!!

						  page_remove_rmap(page)
						    atomic_add_negative(-1, &page->_mapcount)

The second bug[2] is "kernel BUG at mm/huge_memory.c:1371!".
It's VM_BUG_ON_PAGE(!PageHead(page), page) in zap_huge_pmd().

This happens in similar way:

	CPU0						CPU1
						zap_huge_pmd()
						  pmdp_get_and_clear()
						  page_remove_rmap(page)
						    atomic_add_negative(-1, &page->_mapcount)
__split_huge_page()
  anon_vma_interval_tree_foreach()
    __split_huge_page_splitting()
      page_check_address_pmd()
        mm_find_pmd()
	  pmd_present(pmd) == 0	/* The same comment as above */
  /*
   * No crash this time since we already decremented page->_mapcount in
   * zap_huge_pmd().
   */
  BUG_ON(mapcount != page_mapcount(page))

  /*
   * We split the compound page here into small pages without
   * serialization against zap_huge_pmd()
   */
  __split_huge_page_refcount()
						VM_BUG_ON_PAGE(!PageHead(page), page); // CRASH!!!

So my understanding the problem is pmd_present() check in mm_find_pmd()
without taking page table lock.

The bug was introduced by me commit with commit 117b0791ac42. Sorry for
that. :(

Let's open code mm_find_pmd() in page_check_address_pmd() and do the
check under page table lock.

Note that __page_check_address() does the same for PTE entires
if sync != 0.

I've stress tested split and zap code paths for 36+ hours by now and
don't see crashes with the patch applied. Before it took <20 min to
trigger the first bug and few hours for second one (if we ignore
first).

[1] https://lkml.kernel.org/g/<53440991.9090001@oracle.com>
[2] https://lkml.kernel.org/g/<5310C56C.60709@oracle.com>

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit b5a8cad376eebbd8598642697e92a27983aee802 upstream.

[stable 3.12 note]
This commit was supposed to fix a completely other issue. But in 3.12,
with commit f72e7dcdd25229446b102e587ef2f826f76bff28 (mm: let
mm_find_pmd fix buggy race with THP fault), we need this commit as
well (it fixes the issue as a by-product). Hugh Dickins writes:
<== citation starts here>
Fine for this to go in, but there is one catch, which I discovered
when backporting to v3.11: it needed one more hunk.  I haven't checked
your base tree, but if this applies then I believe you need it - most
of the time no problem, but it can case page migration to fail to find
a migration entry it inserted earlier, then BUG_ON(!PageLocked(p)) in
migration_entry_to_page() soon after.  Here's what I wrote back then:

Note on rebase to v3.11: added a hunk to replace the use of
mm_find_pmd() in page_check_address_pmd().  This call had been
similarly replaced by the time of my v3.16 commit, in Kirill
Shutemov's v3.15 b5a8cad376ee ("thp: close race between split and zap
huge pages"): which we do not need as such, since it's fixing v3.13
117b0791ac42 ("mm, thp: move ptl taking inside
page_check_address_pmd()"), from a split page-table-lock series we are
not backporting.  But without this additional hunk, rmap sometimes
broke when the new semantic for mm_find_pmd() was used here.
<== end of citation>

But instead of appending hunks to commits, I am taking a full,
backported version of commit b5a8cad376ee with this note prepended.

So the changelog of b5a8cad376ee is left below, but does not apply to
3.12 yet.
[=== stable 3.12 note ends here]

Sasha Levin has reported two THP BUGs[1][2].  I believe both of them
have the same root cause.  Let's look to them one by one.

The first bug[1] is "kernel BUG at mm/huge_memory.c:1829!".  It's
BUG_ON(mapcount != page_mapcount(page)) in __split_huge_page().  From my
testing I see that page_mapcount() is higher than mapcount here.

I think it happens due to race between zap_huge_pmd() and
page_check_address_pmd().  page_check_address_pmd() misses PMD which is
under zap:

	CPU0						CPU1
						zap_huge_pmd()
						  pmdp_get_and_clear()
__split_huge_page()
  anon_vma_interval_tree_foreach()
    __split_huge_page_splitting()
      page_check_address_pmd()
        mm_find_pmd()
	  /*
	   * We check if PMD present without taking ptl: no
	   * serialization against zap_huge_pmd(). We miss this PMD,
	   * it's not accounted to 'mapcount' in __split_huge_page().
	   */
	  pmd_present(pmd) == 0

  BUG_ON(mapcount != page_mapcount(page)) // CRASH!!!

						  page_remove_rmap(page)
						    atomic_add_negative(-1, &page->_mapcount)

The second bug[2] is "kernel BUG at mm/huge_memory.c:1371!".
It's VM_BUG_ON_PAGE(!PageHead(page), page) in zap_huge_pmd().

This happens in similar way:

	CPU0						CPU1
						zap_huge_pmd()
						  pmdp_get_and_clear()
						  page_remove_rmap(page)
						    atomic_add_negative(-1, &page->_mapcount)
__split_huge_page()
  anon_vma_interval_tree_foreach()
    __split_huge_page_splitting()
      page_check_address_pmd()
        mm_find_pmd()
	  pmd_present(pmd) == 0	/* The same comment as above */
  /*
   * No crash this time since we already decremented page->_mapcount in
   * zap_huge_pmd().
   */
  BUG_ON(mapcount != page_mapcount(page))

  /*
   * We split the compound page here into small pages without
   * serialization against zap_huge_pmd()
   */
  __split_huge_page_refcount()
						VM_BUG_ON_PAGE(!PageHead(page), page); // CRASH!!!

So my understanding the problem is pmd_present() check in mm_find_pmd()
without taking page table lock.

The bug was introduced by me commit with commit 117b0791ac42. Sorry for
that. :(

Let's open code mm_find_pmd() in page_check_address_pmd() and do the
check under page table lock.

Note that __page_check_address() does the same for PTE entires
if sync != 0.

I've stress tested split and zap code paths for 36+ hours by now and
don't see crashes with the patch applied. Before it took <20 min to
trigger the first bug and few hours for second one (if we ignore
first).

[1] https://lkml.kernel.org/g/<53440991.9090001@oracle.com>
[2] https://lkml.kernel.org/g/<5310C56C.60709@oracle.com>

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







perf/x86: Correctly use FEATURE_PDCM
2015-01-10T11:40:17+00:00

Peter Zijlstra
peterz@infradead.org

2014-02-03T13:29:03+00:00

05d75f8aa3a9227b5180354671dff77c9a72d0bf

commit c9b08884c9c98929ec2d8abafd78e89062d01ee7 upstream.

The current code simply assumes Intel Arch PerfMon v2+ to have
the IA32_PERF_CAPABILITIES MSR; the SDM specifies that we should check
CPUID[1].ECX[15] (aka, FEATURE_PDCM) instead.

This was found by KVM which implements v2+ but didn't provide the
capabilities MSR. Change the code to DTRT; KVM will also implement the
MSR and return 0.

Cc: pbonzini@redhat.com
Reported-by: "Michael S. Tsirkin" <mst@redhat.com>
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140203132903.GI8874@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit c9b08884c9c98929ec2d8abafd78e89062d01ee7 upstream.

The current code simply assumes Intel Arch PerfMon v2+ to have
the IA32_PERF_CAPABILITIES MSR; the SDM specifies that we should check
CPUID[1].ECX[15] (aka, FEATURE_PDCM) instead.

This was found by KVM which implements v2+ but didn't provide the
capabilities MSR. Change the code to DTRT; KVM will also implement the
MSR and return 0.

Cc: pbonzini@redhat.com
Reported-by: "Michael S. Tsirkin" <mst@redhat.com>
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140203132903.GI8874@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







mm: let mm_find_pmd fix buggy race with THP fault
2015-01-09T10:28:28+00:00

Hugh Dickins
hughd@google.com

2014-06-23T20:22:05+00:00

e1c34dac913e87ee8d03c06d7a328a7c2137cafb

commit f72e7dcdd25229446b102e587ef2f826f76bff28 upstream.

Trinity has reported:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
    IP: __lock_acquire (kernel/locking/lockdep.c:3070 (discriminator 1))
    CPU: 6 PID: 16173 Comm: trinity-c364 Tainted: G        W
                            3.15.0-rc1-next-20140415-sasha-00020-gaa90d09 #398
    lock_acquire (arch/x86/include/asm/current.h:14
                  kernel/locking/lockdep.c:3602)
    _raw_spin_lock (include/linux/spinlock_api_smp.h:143
                    kernel/locking/spinlock.c:151)
    remove_migration_pte (mm/migrate.c:137)
    rmap_walk (mm/rmap.c:1628 mm/rmap.c:1699)
    remove_migration_ptes (mm/migrate.c:224)
    migrate_pages (mm/migrate.c:922 mm/migrate.c:960 mm/migrate.c:1126)
    migrate_misplaced_page (mm/migrate.c:1733)
    __handle_mm_fault (mm/memory.c:3762 mm/memory.c:3812 mm/memory.c:3925)
    handle_mm_fault (mm/memory.c:3948)
    __get_user_pages (mm/memory.c:1851)
    __mlock_vma_pages_range (mm/mlock.c:255)
    __mm_populate (mm/mlock.c:711)
    SyS_mlockall (include/linux/mm.h:1799 mm/mlock.c:817 mm/mlock.c:791)

I believe this comes about because, whereas collapsing and splitting THP
functions take anon_vma lock in write mode (which excludes concurrent
rmap walks), faulting THP functions (write protection and misplaced
NUMA) do not - and mostly they do not need to.

But they do use a pmdp_clear_flush(), set_pmd_at() sequence which, for
an instant (indeed, for a long instant, given the inter-CPU TLB flush in
there), leaves *pmd neither present not trans_huge.

Which can confuse a concurrent rmap walk, as when removing migration
ptes, seen in the dumped trace.  Although that rmap walk has a 4k page
to insert, anon_vmas containing THPs are in no way segregated from
4k-page anon_vmas, so the 4k-intent mm_find_pmd() does need to cope with
that instant when a trans_huge pmd is temporarily absent.

I don't think we need strengthen the locking at the THP end: it's easily
handled with an ACCESS_ONCE() before testing both conditions.

And since mm_find_pmd() had only one caller who wanted a THP rather than
a pmd, let's slightly repurpose it to fail when it hits a THP or
non-present pmd, and open code split_huge_page_address() again.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Jones <davej@redhat.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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit f72e7dcdd25229446b102e587ef2f826f76bff28 upstream.

Trinity has reported:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
    IP: __lock_acquire (kernel/locking/lockdep.c:3070 (discriminator 1))
    CPU: 6 PID: 16173 Comm: trinity-c364 Tainted: G        W
                            3.15.0-rc1-next-20140415-sasha-00020-gaa90d09 #398
    lock_acquire (arch/x86/include/asm/current.h:14
                  kernel/locking/lockdep.c:3602)
    _raw_spin_lock (include/linux/spinlock_api_smp.h:143
                    kernel/locking/spinlock.c:151)
    remove_migration_pte (mm/migrate.c:137)
    rmap_walk (mm/rmap.c:1628 mm/rmap.c:1699)
    remove_migration_ptes (mm/migrate.c:224)
    migrate_pages (mm/migrate.c:922 mm/migrate.c:960 mm/migrate.c:1126)
    migrate_misplaced_page (mm/migrate.c:1733)
    __handle_mm_fault (mm/memory.c:3762 mm/memory.c:3812 mm/memory.c:3925)
    handle_mm_fault (mm/memory.c:3948)
    __get_user_pages (mm/memory.c:1851)
    __mlock_vma_pages_range (mm/mlock.c:255)
    __mm_populate (mm/mlock.c:711)
    SyS_mlockall (include/linux/mm.h:1799 mm/mlock.c:817 mm/mlock.c:791)

I believe this comes about because, whereas collapsing and splitting THP
functions take anon_vma lock in write mode (which excludes concurrent
rmap walks), faulting THP functions (write protection and misplaced
NUMA) do not - and mostly they do not need to.

But they do use a pmdp_clear_flush(), set_pmd_at() sequence which, for
an instant (indeed, for a long instant, given the inter-CPU TLB flush in
there), leaves *pmd neither present not trans_huge.

Which can confuse a concurrent rmap walk, as when removing migration
ptes, seen in the dumped trace.  Although that rmap walk has a 4k page
to insert, anon_vmas containing THPs are in no way segregated from
4k-page anon_vmas, so the 4k-intent mm_find_pmd() does need to cope with
that instant when a trans_huge pmd is temporarily absent.

I don't think we need strengthen the locking at the THP end: it's easily
handled with an ACCESS_ONCE() before testing both conditions.

And since mm_find_pmd() had only one caller who wanted a THP rather than
a pmd, let's slightly repurpose it to fail when it hits a THP or
non-present pmd, and open code split_huge_page_address() again.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Jones <davej@redhat.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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







mfd: viperboard: Fix platform-device id collision
2015-01-09T10:28:28+00:00

Johan Hovold
johan@kernel.org

2014-09-26T10:55:28+00:00

0702a76da972aa3a3a7091a4e3abe833017a2904

commit b6684228726cc25551a43f5c0bd9c5f977f10f48 upstream.

Allow more than one viperboard to be connected by registering with
PLATFORM_DEVID_AUTO instead of PLATFORM_DEVID_NONE.

The subdevices are currently registered with PLATFORM_DEVID_NONE, which
will cause a name collision on the platform bus when a second viperboard
is plugged in:

viperboard 1-2.4:1.0: version 0.00 found at bus 001 address 004
------------[ cut here ]------------
WARNING: CPU: 0 PID: 181 at /home/johan/work/omicron/src/linux/fs/sysfs/dir.c:31 sysfs_warn_dup+0x74/0x84()
sysfs: cannot create duplicate filename '/bus/platform/devices/viperboard-gpio'
Modules linked in: i2c_viperboard viperboard netconsole [last unloaded: viperboard]
CPU: 0 PID: 181 Comm: bash Tainted: G        W      3.17.0-rc6 #1
[<c0016bf4>] (unwind_backtrace) from [<c0013860>] (show_stack+0x20/0x24)
[<c0013860>] (show_stack) from [<c04305f8>] (dump_stack+0x24/0x28)
[<c04305f8>] (dump_stack) from [<c0040fb4>] (warn_slowpath_common+0x80/0x98)
[<c0040fb4>] (warn_slowpath_common) from [<c004100c>] (warn_slowpath_fmt+0x40/0x48)
[<c004100c>] (warn_slowpath_fmt) from [<c016f1bc>] (sysfs_warn_dup+0x74/0x84)
[<c016f1bc>] (sysfs_warn_dup) from [<c016f548>] (sysfs_do_create_link_sd.isra.2+0xcc/0xd0)
[<c016f548>] (sysfs_do_create_link_sd.isra.2) from [<c016f588>] (sysfs_create_link+0x3c/0x48)
[<c016f588>] (sysfs_create_link) from [<c02867ec>] (bus_add_device+0x12c/0x1e0)
[<c02867ec>] (bus_add_device) from [<c0284820>] (device_add+0x410/0x584)
[<c0284820>] (device_add) from [<c0289440>] (platform_device_add+0xd8/0x26c)
[<c0289440>] (platform_device_add) from [<c02a5ae4>] (mfd_add_device+0x240/0x344)
[<c02a5ae4>] (mfd_add_device) from [<c02a5ce0>] (mfd_add_devices+0xb8/0x110)
[<c02a5ce0>] (mfd_add_devices) from [<bf00d1c8>] (vprbrd_probe+0x160/0x1b0 [viperboard])
[<bf00d1c8>] (vprbrd_probe [viperboard]) from [<c030c000>] (usb_probe_interface+0x1bc/0x2a8)
[<c030c000>] (usb_probe_interface) from [<c028768c>] (driver_probe_device+0x14c/0x3ac)
[<c028768c>] (driver_probe_device) from [<c02879e4>] (__driver_attach+0xa4/0xa8)
[<c02879e4>] (__driver_attach) from [<c0285698>] (bus_for_each_dev+0x70/0xa4)
[<c0285698>] (bus_for_each_dev) from [<c0287030>] (driver_attach+0x2c/0x30)
[<c0287030>] (driver_attach) from [<c030a288>] (usb_store_new_id+0x170/0x1ac)
[<c030a288>] (usb_store_new_id) from [<c030a2f8>] (new_id_store+0x34/0x3c)
[<c030a2f8>] (new_id_store) from [<c02853ec>] (drv_attr_store+0x30/0x3c)
[<c02853ec>] (drv_attr_store) from [<c016eaa8>] (sysfs_kf_write+0x5c/0x60)
[<c016eaa8>] (sysfs_kf_write) from [<c016dc68>] (kernfs_fop_write+0xd4/0x194)
[<c016dc68>] (kernfs_fop_write) from [<c010fe40>] (vfs_write+0xb4/0x1c0)
[<c010fe40>] (vfs_write) from [<c01104a8>] (SyS_write+0x4c/0xa0)
[<c01104a8>] (SyS_write) from [<c000f900>] (ret_fast_syscall+0x0/0x48)
---[ end trace 98e8603c22d65817 ]---
viperboard 1-2.4:1.0: Failed to add mfd devices to core.
viperboard: probe of 1-2.4:1.0 failed with error -17

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit b6684228726cc25551a43f5c0bd9c5f977f10f48 upstream.

Allow more than one viperboard to be connected by registering with
PLATFORM_DEVID_AUTO instead of PLATFORM_DEVID_NONE.

The subdevices are currently registered with PLATFORM_DEVID_NONE, which
will cause a name collision on the platform bus when a second viperboard
is plugged in:

viperboard 1-2.4:1.0: version 0.00 found at bus 001 address 004
------------[ cut here ]------------
WARNING: CPU: 0 PID: 181 at /home/johan/work/omicron/src/linux/fs/sysfs/dir.c:31 sysfs_warn_dup+0x74/0x84()
sysfs: cannot create duplicate filename '/bus/platform/devices/viperboard-gpio'
Modules linked in: i2c_viperboard viperboard netconsole [last unloaded: viperboard]
CPU: 0 PID: 181 Comm: bash Tainted: G        W      3.17.0-rc6 #1
[<c0016bf4>] (unwind_backtrace) from [<c0013860>] (show_stack+0x20/0x24)
[<c0013860>] (show_stack) from [<c04305f8>] (dump_stack+0x24/0x28)
[<c04305f8>] (dump_stack) from [<c0040fb4>] (warn_slowpath_common+0x80/0x98)
[<c0040fb4>] (warn_slowpath_common) from [<c004100c>] (warn_slowpath_fmt+0x40/0x48)
[<c004100c>] (warn_slowpath_fmt) from [<c016f1bc>] (sysfs_warn_dup+0x74/0x84)
[<c016f1bc>] (sysfs_warn_dup) from [<c016f548>] (sysfs_do_create_link_sd.isra.2+0xcc/0xd0)
[<c016f548>] (sysfs_do_create_link_sd.isra.2) from [<c016f588>] (sysfs_create_link+0x3c/0x48)
[<c016f588>] (sysfs_create_link) from [<c02867ec>] (bus_add_device+0x12c/0x1e0)
[<c02867ec>] (bus_add_device) from [<c0284820>] (device_add+0x410/0x584)
[<c0284820>] (device_add) from [<c0289440>] (platform_device_add+0xd8/0x26c)
[<c0289440>] (platform_device_add) from [<c02a5ae4>] (mfd_add_device+0x240/0x344)
[<c02a5ae4>] (mfd_add_device) from [<c02a5ce0>] (mfd_add_devices+0xb8/0x110)
[<c02a5ce0>] (mfd_add_devices) from [<bf00d1c8>] (vprbrd_probe+0x160/0x1b0 [viperboard])
[<bf00d1c8>] (vprbrd_probe [viperboard]) from [<c030c000>] (usb_probe_interface+0x1bc/0x2a8)
[<c030c000>] (usb_probe_interface) from [<c028768c>] (driver_probe_device+0x14c/0x3ac)
[<c028768c>] (driver_probe_device) from [<c02879e4>] (__driver_attach+0xa4/0xa8)
[<c02879e4>] (__driver_attach) from [<c0285698>] (bus_for_each_dev+0x70/0xa4)
[<c0285698>] (bus_for_each_dev) from [<c0287030>] (driver_attach+0x2c/0x30)
[<c0287030>] (driver_attach) from [<c030a288>] (usb_store_new_id+0x170/0x1ac)
[<c030a288>] (usb_store_new_id) from [<c030a2f8>] (new_id_store+0x34/0x3c)
[<c030a2f8>] (new_id_store) from [<c02853ec>] (drv_attr_store+0x30/0x3c)
[<c02853ec>] (drv_attr_store) from [<c016eaa8>] (sysfs_kf_write+0x5c/0x60)
[<c016eaa8>] (sysfs_kf_write) from [<c016dc68>] (kernfs_fop_write+0xd4/0x194)
[<c016dc68>] (kernfs_fop_write) from [<c010fe40>] (vfs_write+0xb4/0x1c0)
[<c010fe40>] (vfs_write) from [<c01104a8>] (SyS_write+0x4c/0xa0)
[<c01104a8>] (SyS_write) from [<c000f900>] (ret_fast_syscall+0x0/0x48)
---[ end trace 98e8603c22d65817 ]---
viperboard 1-2.4:1.0: Failed to add mfd devices to core.
viperboard: probe of 1-2.4:1.0 failed with error -17

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







mfd: stmpe: Fix STMPE24xx GPMR LSB
2015-01-09T10:28:27+00:00

Linus Walleij
linus.walleij@linaro.org

2014-10-04T14:02:27+00:00

83ee596143c7f78fec7c8f36f92be2223d9a8bad

commit 871c3cf4ea7d5baf58e0a40bce7431ca5525aa2a upstream.

The least significat byte of the GPIO value read register
on the STMPE24xx series is on addres 0xA4 not 0xA5. Correct
against datasheet and tested on the STMPE2401 hardware.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit 871c3cf4ea7d5baf58e0a40bce7431ca5525aa2a upstream.

The least significat byte of the GPIO value read register
on the STMPE24xx series is on addres 0xA4 not 0xA5. Correct
against datasheet and tested on the STMPE2401 hardware.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







Btrfs: fix fs corruption on transaction abort if device supports discard
2015-01-07T16:55:20+00:00

Filipe Manana
fdmanana@suse.com

2014-12-07T21:31:47+00:00

bc5e18c1dc407bd245a190076d362ecf7975e64a

commit 678886bdc6378c1cbd5072da2c5a3035000214e3 upstream.

When we abort a transaction we iterate over all the ranges marked as dirty
in fs_info->freed_extents[0] and fs_info->freed_extents[1], clear them
from those trees, add them back (unpin) to the free space caches and, if
the fs was mounted with "-o discard", perform a discard on those regions.
Also, after adding the regions to the free space caches, a fitrim ioctl call
can see those ranges in a block group's free space cache and perform a discard
on the ranges, so the same issue can happen without "-o discard" as well.

This causes corruption, affecting one or multiple btree nodes (in the worst
case leaving the fs unmountable) because some of those ranges (the ones in
the fs_info->pinned_extents tree) correspond to btree nodes/leafs that are
referred by the last committed super block - breaking the rule that anything
that was committed by a transaction is untouched until the next transaction
commits successfully.

I ran into this while running in a loop (for several hours) the fstest that
I recently submitted:

  [PATCH] fstests: add btrfs test to stress chunk allocation/removal and fstrim

The corruption always happened when a transaction aborted and then fsck complained
like this:

   _check_btrfs_filesystem: filesystem on /dev/sdc is inconsistent
   *** fsck.btrfs output ***
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   read block failed check_tree_block
   Couldn't open file system

In this case 94945280 corresponded to the root of a tree.
Using frace what I observed was the following sequence of steps happened:

   1) transaction N started, fs_info->pinned_extents pointed to
      fs_info->freed_extents[0];

   2) node/eb 94945280 is created;

   3) eb is persisted to disk;

   4) transaction N commit starts, fs_info->pinned_extents now points to
      fs_info->freed_extents[1], and transaction N completes;

   5) transaction N + 1 starts;

   6) eb is COWed, and btrfs_free_tree_block() called for this eb;

   7) eb range (94945280 to 94945280 + 16Kb) is added to
      fs_info->pinned_extents (fs_info->freed_extents[1]);

   8) Something goes wrong in transaction N + 1, like hitting ENOSPC
      for example, and the transaction is aborted, turning the fs into
      readonly mode. The stack trace I got for example:

      [112065.253935]  [<ffffffff8140c7b6>] dump_stack+0x4d/0x66
      [112065.254271]  [<ffffffff81042984>] warn_slowpath_common+0x7f/0x98
      [112065.254567]  [<ffffffffa0325990>] ? __btrfs_abort_transaction+0x50/0x10b [btrfs]
      [112065.261674]  [<ffffffff810429e5>] warn_slowpath_fmt+0x48/0x50
      [112065.261922]  [<ffffffffa032949e>] ? btrfs_free_path+0x26/0x29 [btrfs]
      [112065.262211]  [<ffffffffa0325990>] __btrfs_abort_transaction+0x50/0x10b [btrfs]
      [112065.262545]  [<ffffffffa036b1d6>] btrfs_remove_chunk+0x537/0x58b [btrfs]
      [112065.262771]  [<ffffffffa033840f>] btrfs_delete_unused_bgs+0x1de/0x21b [btrfs]
      [112065.263105]  [<ffffffffa0343106>] cleaner_kthread+0x100/0x12f [btrfs]
      (...)
      [112065.264493] ---[ end trace dd7903a975a31a08 ]---
      [112065.264673] BTRFS: error (device sdc) in btrfs_remove_chunk:2625: errno=-28 No space left
      [112065.264997] BTRFS info (device sdc): forced readonly

   9) The clear kthread sees that the BTRFS_FS_STATE_ERROR bit is set in
      fs_info->fs_state and calls btrfs_cleanup_transaction(), which in
      turn calls btrfs_destroy_pinned_extent();

   10) Then btrfs_destroy_pinned_extent() iterates over all the ranges
       marked as dirty in fs_info->freed_extents[], and for each one
       it calls discard, if the fs was mounted with "-o discard", and
       adds the range to the free space cache of the respective block
       group;

   11) btrfs_trim_block_group(), invoked from the fitrim ioctl code path,
       sees the free space entries and performs a discard;

   12) After an umount and mount (or fsck), our eb's location on disk was full
       of zeroes, and it should have been untouched, because it was marked as
       dirty in the fs_info->pinned_extents tree, and therefore used by the
       trees that the last committed superblock points to.

Fix this by not performing a discard and not adding the ranges to the free space
caches - it's useless from this point since the fs is now in readonly mode and
we won't write free space caches to disk anymore (otherwise we would leak space)
nor any new superblock. By not adding the ranges to the free space caches, it
prevents other code paths from allocating that space and write to it as well,
therefore being safer and simpler.

This isn't a new problem, as it's been present since 2011 (git commit
acce952b0263825da32cf10489413dec78053347).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit 678886bdc6378c1cbd5072da2c5a3035000214e3 upstream.

When we abort a transaction we iterate over all the ranges marked as dirty
in fs_info->freed_extents[0] and fs_info->freed_extents[1], clear them
from those trees, add them back (unpin) to the free space caches and, if
the fs was mounted with "-o discard", perform a discard on those regions.
Also, after adding the regions to the free space caches, a fitrim ioctl call
can see those ranges in a block group's free space cache and perform a discard
on the ranges, so the same issue can happen without "-o discard" as well.

This causes corruption, affecting one or multiple btree nodes (in the worst
case leaving the fs unmountable) because some of those ranges (the ones in
the fs_info->pinned_extents tree) correspond to btree nodes/leafs that are
referred by the last committed super block - breaking the rule that anything
that was committed by a transaction is untouched until the next transaction
commits successfully.

I ran into this while running in a loop (for several hours) the fstest that
I recently submitted:

  [PATCH] fstests: add btrfs test to stress chunk allocation/removal and fstrim

The corruption always happened when a transaction aborted and then fsck complained
like this:

   _check_btrfs_filesystem: filesystem on /dev/sdc is inconsistent
   *** fsck.btrfs output ***
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   Check tree block failed, want=94945280, have=0
   read block failed check_tree_block
   Couldn't open file system

In this case 94945280 corresponded to the root of a tree.
Using frace what I observed was the following sequence of steps happened:

   1) transaction N started, fs_info->pinned_extents pointed to
      fs_info->freed_extents[0];

   2) node/eb 94945280 is created;

   3) eb is persisted to disk;

   4) transaction N commit starts, fs_info->pinned_extents now points to
      fs_info->freed_extents[1], and transaction N completes;

   5) transaction N + 1 starts;

   6) eb is COWed, and btrfs_free_tree_block() called for this eb;

   7) eb range (94945280 to 94945280 + 16Kb) is added to
      fs_info->pinned_extents (fs_info->freed_extents[1]);

   8) Something goes wrong in transaction N + 1, like hitting ENOSPC
      for example, and the transaction is aborted, turning the fs into
      readonly mode. The stack trace I got for example:

      [112065.253935]  [<ffffffff8140c7b6>] dump_stack+0x4d/0x66
      [112065.254271]  [<ffffffff81042984>] warn_slowpath_common+0x7f/0x98
      [112065.254567]  [<ffffffffa0325990>] ? __btrfs_abort_transaction+0x50/0x10b [btrfs]
      [112065.261674]  [<ffffffff810429e5>] warn_slowpath_fmt+0x48/0x50
      [112065.261922]  [<ffffffffa032949e>] ? btrfs_free_path+0x26/0x29 [btrfs]
      [112065.262211]  [<ffffffffa0325990>] __btrfs_abort_transaction+0x50/0x10b [btrfs]
      [112065.262545]  [<ffffffffa036b1d6>] btrfs_remove_chunk+0x537/0x58b [btrfs]
      [112065.262771]  [<ffffffffa033840f>] btrfs_delete_unused_bgs+0x1de/0x21b [btrfs]
      [112065.263105]  [<ffffffffa0343106>] cleaner_kthread+0x100/0x12f [btrfs]
      (...)
      [112065.264493] ---[ end trace dd7903a975a31a08 ]---
      [112065.264673] BTRFS: error (device sdc) in btrfs_remove_chunk:2625: errno=-28 No space left
      [112065.264997] BTRFS info (device sdc): forced readonly

   9) The clear kthread sees that the BTRFS_FS_STATE_ERROR bit is set in
      fs_info->fs_state and calls btrfs_cleanup_transaction(), which in
      turn calls btrfs_destroy_pinned_extent();

   10) Then btrfs_destroy_pinned_extent() iterates over all the ranges
       marked as dirty in fs_info->freed_extents[], and for each one
       it calls discard, if the fs was mounted with "-o discard", and
       adds the range to the free space cache of the respective block
       group;

   11) btrfs_trim_block_group(), invoked from the fitrim ioctl code path,
       sees the free space entries and performs a discard;

   12) After an umount and mount (or fsck), our eb's location on disk was full
       of zeroes, and it should have been untouched, because it was marked as
       dirty in the fs_info->pinned_extents tree, and therefore used by the
       trees that the last committed superblock points to.

Fix this by not performing a discard and not adding the ranges to the free space
caches - it's useless from this point since the fs is now in readonly mode and
we won't write free space caches to disk anymore (otherwise we would leak space)
nor any new superblock. By not adding the ranges to the free space caches, it
prevents other code paths from allocating that space and write to it as well,
therefore being safer and simpler.

This isn't a new problem, as it's been present since 2011 (git commit
acce952b0263825da32cf10489413dec78053347).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







Btrfs: do not move em to modified list when unpinning
2015-01-07T16:55:20+00:00

Josef Bacik
jbacik@fb.com

2014-11-14T21:16:30+00:00

f25952649585cdd0643741a50d02d600fcc28ef2

commit a28046956c71985046474283fa3bcd256915fb72 upstream.

We use the modified list to keep track of which extents have been modified so we
know which ones are candidates for logging at fsync() time.  Newly modified
extents are added to the list at modification time, around the same time the
ordered extent is created.  We do this so that we don't have to wait for ordered
extents to complete before we know what we need to log.  The problem is when
something like this happens

log extent 0-4k on inode 1
copy csum for 0-4k from ordered extent into log
sync log
commit transaction
log some other extent on inode 1
ordered extent for 0-4k completes and adds itself onto modified list again
log changed extents
see ordered extent for 0-4k has already been logged
	at this point we assume the csum has been copied
sync log
crash

On replay we will see the extent 0-4k in the log, drop the original 0-4k extent
which is the same one that we are replaying which also drops the csum, and then
we won't find the csum in the log for that bytenr.  This of course causes us to
have errors about not having csums for certain ranges of our inode.  So remove
the modified list manipulation in unpin_extent_cache, any modified extents
should have been added well before now, and we don't want them re-logged.  This
fixes my test that I could reliably reproduce this problem with.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit a28046956c71985046474283fa3bcd256915fb72 upstream.

We use the modified list to keep track of which extents have been modified so we
know which ones are candidates for logging at fsync() time.  Newly modified
extents are added to the list at modification time, around the same time the
ordered extent is created.  We do this so that we don't have to wait for ordered
extents to complete before we know what we need to log.  The problem is when
something like this happens

log extent 0-4k on inode 1
copy csum for 0-4k from ordered extent into log
sync log
commit transaction
log some other extent on inode 1
ordered extent for 0-4k completes and adds itself onto modified list again
log changed extents
see ordered extent for 0-4k has already been logged
	at this point we assume the csum has been copied
sync log
crash

On replay we will see the extent 0-4k in the log, drop the original 0-4k extent
which is the same one that we are replaying which also drops the csum, and then
we won't find the csum in the log for that bytenr.  This of course causes us to
have errors about not having csums for certain ranges of our inode.  So remove
the modified list manipulation in unpin_extent_cache, any modified extents
should have been added well before now, and we don't want them re-logged.  This
fixes my test that I could reliably reproduce this problem with.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







eCryptfs: Remove buggy and unnecessary write in file name decode routine
2015-01-07T16:55:19+00:00

Michael Halcrow
mhalcrow@google.com

2014-11-26T17:09:16+00:00

8ffea99d6f2be99790611282f326da95a84a8cab

commit 942080643bce061c3dd9d5718d3b745dcb39a8bc upstream.

Dmitry Chernenkov used KASAN to discover that eCryptfs writes past the
end of the allocated buffer during encrypted filename decoding. This
fix corrects the issue by getting rid of the unnecessary 0 write when
the current bit offset is 2.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Reported-by: Dmitry Chernenkov <dmitryc@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit 942080643bce061c3dd9d5718d3b745dcb39a8bc upstream.

Dmitry Chernenkov used KASAN to discover that eCryptfs writes past the
end of the allocated buffer during encrypted filename decoding. This
fix corrects the issue by getting rid of the unnecessary 0 write when
the current bit offset is 2.

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Reported-by: Dmitry Chernenkov <dmitryc@google.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>







eCryptfs: Force RO mount when encrypted view is enabled
2015-01-07T16:55:19+00:00

Tyler Hicks
tyhicks@canonical.com

2014-10-07T20:51:55+00:00

c1b5e3f84f560038d9a71b19d6b0db933140a613

commit 332b122d39c9cbff8b799007a825d94b2e7c12f2 upstream.

The ecryptfs_encrypted_view mount option greatly changes the
functionality of an eCryptfs mount. Instead of encrypting and decrypting
lower files, it provides a unified view of the encrypted files in the
lower filesystem. The presence of the ecryptfs_encrypted_view mount
option is intended to force a read-only mount and modifying files is not
supported when the feature is in use. See the following commit for more
information:

  e77a56d [PATCH] eCryptfs: Encrypted passthrough

This patch forces the mount to be read-only when the
ecryptfs_encrypted_view mount option is specified by setting the
MS_RDONLY flag on the superblock. Additionally, this patch removes some
broken logic in ecryptfs_open() that attempted to prevent modifications
of files when the encrypted view feature was in use. The check in
ecryptfs_open() was not sufficient to prevent file modifications using
system calls that do not operate on a file descriptor.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Priya Bansal <p.bansal@samsung.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>





commit 332b122d39c9cbff8b799007a825d94b2e7c12f2 upstream.

The ecryptfs_encrypted_view mount option greatly changes the
functionality of an eCryptfs mount. Instead of encrypting and decrypting
lower files, it provides a unified view of the encrypted files in the
lower filesystem. The presence of the ecryptfs_encrypted_view mount
option is intended to force a read-only mount and modifying files is not
supported when the feature is in use. See the following commit for more
information:

  e77a56d [PATCH] eCryptfs: Encrypted passthrough

This patch forces the mount to be read-only when the
ecryptfs_encrypted_view mount option is specified by setting the
MS_RDONLY flag on the superblock. Additionally, this patch removes some
broken logic in ecryptfs_open() that attempted to prevent modifications
of files when the encrypted view feature was in use. The check in
ecryptfs_open() was not sufficient to prevent file modifications using
system calls that do not operate on a file descriptor.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Priya Bansal <p.bansal@samsung.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>