Pull powerpc fix from Ben Herrenschmidt: "Here's just one trivial patch to wire up sys_renameat2 which I seem to have completely missed so far. (My test build scripts fwd me warnings but miss the ones generated for missing syscalls)" * 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: powerpc: Wire renameat2() syscall
Pull MIPS fixes from Ralf Baechle: "A fair number of fixes across the field. Nothing terribly complicated; the one liners in below changelog should be fairly descriptive. Noteworthy is the SB1 change which the result of changes to binutils resulting in one big gas warning for most files being assembled as well as the asid_cache and branch emulation fixes which fix corruption or possible uninteded behaviour of kernel or application code. The remainder of fixes are more platforms or subsystem specific" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: MIPS: R46000: Fix Micro-assembler field overflow for R4600 V2 MIPS: ptrace: Avoid smp_processor_id() in preemptible code MIPS: Lemote 2F: cs5536: mfgpt: use raw locks MIPS: SB1: Fix excessive kernel warnings. MIPS: RC32434: fix broken PCI resource initialization MIPS: malta: memory.c: Initialize the 'memsize' variable MIPS: Fix typo when reporting cache and ftlb errors for ImgTec cores MIPS: Fix inconsistancy of __NR_Linux_syscalls value MIPS: Fix branch emulation of branch likely instructions. MIPS: Fix a typo error in AUDIT_ARCH definition MIPS: Change type of asid_cache to unsigned long
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
While I play inhouse patches with much memory pressure on qemu-kvm,
3.14 kernel was randomly crashed. The reason was kernel stack overflow.
When I investigated the problem, the callstack was a little bit deeper
by involve with reclaim functions but not direct reclaim path.
I tried to diet stack size of some functions related with alloc/reclaim
so did a hundred of byte but overflow was't disappeard so that I encounter
overflow by another deeper callstack on reclaim/allocator path.
Of course, we might sweep every sites we have found for reducing
stack usage but I'm not sure how long it saves the world(surely,
lots of developer start to add nice features which will use stack
agains) and if we consider another more complex feature in I/O layer
and/or reclaim path, it might be better to increase stack size(
meanwhile, stack usage on 64bit machine was doubled compared to 32bit
while it have sticked to 8K. Hmm, it's not a fair to me and arm64
already expaned to 16K. )
So, my stupid idea is just let's expand stack size and keep an eye
toward stack consumption on each kernel functions via stacktrace of ftrace.
For example, we can have a bar like that each funcion shouldn't exceed 200K
and emit the warning when some function consumes more in runtime.
Of course, it could make false positive but at least, it could make a
chance to think over it.
I guess this topic was discussed several time so there might be
strong reason not to increase kernel stack size on x86_64, for me not
knowing so Ccing x86_64 maintainers, other MM guys and virtio
maintainers.
Here's an example call trace using up the kernel stack:
Depth Size Location (51 entries)
----- ---- --------
0) 7696 16 lookup_address
1) 7680 16 _lookup_address_cpa.isra.3
2) 7664 24 __change_page_attr_set_clr
3) 7640 392 kernel_map_pages
4) 7248 256 get_page_from_freelist
5) 6992 352 __alloc_pages_nodemask
6) 6640 8 alloc_pages_current
7) 6632 168 new_slab
8) 6464 8 __slab_alloc
9) 6456 80 __kmalloc
10) 6376 376 vring_add_indirect
11) 6000 144 virtqueue_add_sgs
12) 5856 288 __virtblk_add_req
13) 5568 96 virtio_queue_rq
14) 5472 128 __blk_mq_run_hw_queue
15) 5344 16 blk_mq_run_hw_queue
16) 5328 96 blk_mq_insert_requests
17) 5232 112 blk_mq_flush_plug_list
18) 5120 112 blk_flush_plug_list
19) 5008 64 io_schedule_timeout
20) 4944 128 mempool_alloc
21) 4816 96 bio_alloc_bioset
22) 4720 48 get_swap_bio
23) 4672 160 __swap_writepage
24) 4512 32 swap_writepage
25) 4480 320 shrink_page_list
26) 4160 208 shrink_inactive_list
27) 3952 304 shrink_lruvec
28) 3648 80 shrink_zone
29) 3568 128 do_try_to_free_pages
30) 3440 208 try_to_free_pages
31) 3232 352 __alloc_pages_nodemask
32) 2880 8 alloc_pages_current
33) 2872 200 __page_cache_alloc
34) 2672 80 find_or_create_page
35) 2592 80 ext4_mb_load_buddy
36) 2512 176 ext4_mb_regular_allocator
37) 2336 128 ext4_mb_new_blocks
38) 2208 256 ext4_ext_map_blocks
39) 1952 160 ext4_map_blocks
40) 1792 384 ext4_writepages
41) 1408 16 do_writepages
42) 1392 96 __writeback_single_inode
43) 1296 176 writeback_sb_inodes
44) 1120 80 __writeback_inodes_wb
45) 1040 160 wb_writeback
46) 880 208 bdi_writeback_workfn
47) 672 144 process_one_work
48) 528 112 worker_thread
49) 416 240 kthread
50) 176 176 ret_from_fork
[ Note: the problem is exacerbated by certain gcc versions that seem to
generate much bigger stack frames due to apparently bad coalescing of
temporaries and generating too many spills. Rusty saw gcc-4.6.4 using
35% more stack on the virtio path than 4.8.2 does, for example.
Minchan not only uses such a bad gcc version (4.6.3 in his case), but
some of the stack use is due to debugging (CONFIG_DEBUG_PAGEALLOC is
what causes that kernel_map_pages() frame, for example). But we're
clearly getting too close.
The VM code also seems to have excessive stack frames partly for the
same compiler reason, triggered by excessive inlining and lots of
function arguments.
We need to improve on our stack use, but in the meantime let's do this
simple stack increase too. Unlike most earlier reports, there is
nothing simple that stands out as being really horribly wrong here,
apart from the fact that the stack frames are just bigger than they
should need to be. - Linus ]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S Tsirkin <mst@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: PJ Waskiewicz <pjwaskiewicz@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ARM fixes from Russell King: "The usual random collection of relatively small ARM fixes" * 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: ARM: 8063/1: bL_switcher: fix individual online status reporting of removed CPUs ARM: 8064/1: fix v7-M signal return ARM: 8057/1: amba: Add Qualcomm vendor ID. ARM: 8052/1: unwind: Fix handling of "Pop r4-r[4+nnn],r14" opcode ARM: 8051/1: put_user: fix possible data corruption in put_user ARM: 8048/1: fix v7-M setup stack location
Pull arm64 fix from Will Deacon: "Fix CoW regression for transparent hugepages by routing set_pmd_at to set_pte_at, which correctly handles PTE_WRITE and will mark the resulting table entry as read-only where appropriate" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: mm: fix pmd_write CoW brokenness
Commit 9c7e535fcc17 ("arm64: mm: Route pmd thp functions through pte
equivalents") changed the pmd manipulator and accessor functions to
convert the target pmd to a pte, process it with the pte functions, then
convert it back. Along the way, we gained support for PTE_WRITE, however
this is completely ignored by set_pmd_at, and so we fail to set the
PMD_SECT_RDONLY for PMDs, resulting in all sorts of lovely failures (like
CoW not working).
Partially reverting the offending commit (by making use of
PMD_SECT_RDONLY explicitly for pmd_{write,wrprotect,mkwrite} functions)
leads to further issues because pmd_write can then return potentially
incorrect values for page table entries marked as RDONLY, leading to
BUG_ON(pmd_write(entry)) tripping under some THP workloads.
This patch fixes the issue by routing set_pmd_at through set_pte_at,
which correctly takes the PTE_WRITE flag into account. Given that
THP mappings are always anonymous, the additional cache-flushing code
in __sync_icache_dcache won't impose any significant overhead as the
flush will be skipped.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The content of /sys/devices/system/cpu/cpu*/online is still 1 for those
CPUs that the switcher has removed even though the global state in
/sys/devices/system/cpu/online is updated correctly.
It turns out that commit 0902a9044f ("Driver core: Use generic
offline/online for CPU offline/online") has changed the way those files
retrieve their content by relying on on the generic attribute handling
code. The switcher, by calling cpu_down() directly, bypasses this
handling and the attribute value doesn't get updated.
Fix this by calling device_offline()/device_online() instead.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull kvm fixes from Paolo Bonzini: "Small fixes for x86, slightly larger fixes for PPC, and a forgotten s390 patch. The PPC fixes are important because they fix breakage that is new in 3.15" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: s390: announce irqfd capability KVM: x86: disable master clock if TSC is reset during suspend KVM: vmx: disable APIC virtualization in nested guests KVM guest: Make pv trampoline code executable KVM: PPC: Book3S: ifdef on CONFIG_KVM_BOOK3S_32_HANDLER for 32bit KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit KVM: PPC: Book3S: HV: make _PAGE_NUMA take effect
Pull two powerpc fixes from Ben Herrenschmidt: "Here's a pair of powerpc fixes for 3.15 which are also going to stable. One's a fix for building with newer binutils (the problem currently only affects the BookE kernels but the affected macro might come back into use on BookS platforms at any time). Unfortunately, the binutils maintainer did a backward incompatible change to a construct that we use so we have to add Makefile check. The other one is a fix for CPUs getting stuck in kexec when running single threaded. Since we routinely use kexec on power (including in our newer bootloaders), I deemed that important enough" * 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode powerpc: Fix 64 bit builds with binutils 2.24