Currently, unreserve_highatomic_pageblock bails out if it found
highatomic pageblock regardless of really moving free pages from the one
so that it could mitigate unreserve logic's goal which saves OOM of a
process.

This patch makes unreserve functions bail out only if it moves some
pages out of !highatomic free list to avoid such false positive.

Another potential problem is that by race between page freeing and
reserve highatomic function, pages could be in highatomic free list even
though the pageblock is !high atomic migratetype.  In that case,
unreserve_highatomic_pageblock can be void if count of highatomic
reserve is less than pageblock_nr_pages.  We could solve it simply via
draining all of reserved pages before the OOM.  It would have a
safeguard role to exhuast reserved pages before converging to OOM.

Link: http://lkml.kernel.org/r/1476259429-18279-5-git-send-email-minchan@kernel.org


Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I got OOM report from production team with v4.4 kernel.  It had enough
free memory but failed to allocate GFP_KERNEL order-0 page and finally
encountered OOM kill.  It occured during QA process which launches
several apps, switching and so on.  It happned rarely.  IOW, In normal
situation, it was not a problem but if we are unluck so that several
apps uses peak memory at the same time, it can happen.  If we manage to
pass the phase, the system can go working well.

I could reproduce it with my test(memory spike easily.  Look at below.

The reason is free pages(19M) of DMA32 zone are reserved for
HIGHORDERATOMIC and doesn't unreserved before the OOM.

  balloon invoked oom-killer: gfp_mask=0x24280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), order=0, oom_score_adj=0
  balloon cpuset=/ mems_allowed=0
  CPU: 1 PID: 8473 Comm: balloon Tainted: G        W  OE   4.8.0-rc7-00219-g3f74c9559583-dirty #3161
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  Call Trace:
    dump_stack+0x63/0x90
    dump_header+0x5c/0x1ce
    oom_kill_process+0x22e/0x400
    out_of_memory+0x1ac/0x210
    __alloc_pages_nodemask+0x101e/0x1040
    handle_mm_fault+0xa0a/0xbf0
    __do_page_fault+0x1dd/0x4d0
    trace_do_page_fault+0x43/0x130
    do_async_page_fault+0x1a/0xa0
    async_page_fault+0x28/0x30
  Mem-Info:
  active_anon:383949 inactive_anon:106724 isolated_anon:0
   active_file:15 inactive_file:44 isolated_file:0
   unevictable:0 dirty:0 writeback:24 unstable:0
   slab_reclaimable:2483 slab_unreclaimable:3326
   mapped:0 shmem:0 pagetables:1906 bounce:0
   free:6898 free_pcp:291 free_cma:0
  Node 0 active_anon:1535796kB inactive_anon:426896kB active_file:60kB inactive_file:176kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:96kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:1418 all_unreclaimable? no
  DMA free:8188kB min:44kB low:56kB high:68kB active_anon:7648kB inactive_anon:0kB active_file:0kB inactive_file:4kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:20kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
  lowmem_reserve[]: 0 1952 1952 1952
  DMA32 free:19404kB min:5628kB low:7624kB high:9620kB active_anon:1528148kB inactive_anon:426896kB active_file:60kB inactive_file:420kB unevictable:0kB writepending:96kB present:2080640kB managed:2030092kB mlocked:0kB slab_reclaimable:9932kB slab_unreclaimable:13284kB kernel_stack:2496kB pagetables:7624kB bounce:0kB free_pcp:900kB local_pcp:112kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 0
  DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 2*4096kB (H) = 8192kB
  DMA32: 7*4kB (H) 8*8kB (H) 30*16kB (H) 31*32kB (H) 14*64kB (H) 9*128kB (H) 2*256kB (H) 2*512kB (H) 4*1024kB (H) 5*2048kB (H) 0*4096kB = 19484kB
  51131 total pagecache pages
  50795 pages in swap cache
  Swap cache stats: add 3532405601, delete 3532354806, find 124289150/1822712228
  Free swap  = 8kB
  Total swap = 255996kB
  524158 pages RAM
  0 pages HighMem/MovableOnly
  12658 pages reserved
  0 pages cma reserved
  0 pages hwpoisoned

Another example exceeded the limit by the race is

  in:imklog: page allocation failure: order:0, mode:0x2280020(GFP_ATOMIC|__GFP_NOTRACK)
  CPU: 0 PID: 476 Comm: in:imklog Tainted: G            E   4.8.0-rc7-00217-g266ef83c51e5-dirty #3135
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  Call Trace:
    dump_stack+0x63/0x90
    warn_alloc_failed+0xdb/0x130
    __alloc_pages_nodemask+0x4d6/0xdb0
    new_slab+0x339/0x490
    ___slab_alloc.constprop.74+0x367/0x480
    __slab_alloc.constprop.73+0x20/0x40
    __kmalloc+0x1a4/0x1e0
    alloc_indirect.isra.14+0x1d/0x50
    virtqueue_add_sgs+0x1c4/0x470
    __virtblk_add_req+0xae/0x1f0
    virtio_queue_rq+0x12d/0x290
    __blk_mq_run_hw_queue+0x239/0x370
    blk_mq_run_hw_queue+0x8f/0xb0
    blk_mq_insert_requests+0x18c/0x1a0
    blk_mq_flush_plug_list+0x125/0x140
    blk_flush_plug_list+0xc7/0x220
    blk_finish_plug+0x2c/0x40
    __do_page_cache_readahead+0x196/0x230
    filemap_fault+0x448/0x4f0
    ext4_filemap_fault+0x36/0x50
    __do_fault+0x75/0x140
    handle_mm_fault+0x84d/0xbe0
    __do_page_fault+0x1dd/0x4d0
    trace_do_page_fault+0x43/0x130
    do_async_page_fault+0x1a/0xa0
    async_page_fault+0x28/0x30
  Mem-Info:
  active_anon:363826 inactive_anon:121283 isolated_anon:32
   active_file:65 inactive_file:152 isolated_file:0
   unevictable:0 dirty:0 writeback:46 unstable:0
   slab_reclaimable:2778 slab_unreclaimable:3070
   mapped:112 shmem:0 pagetables:1822 bounce:0
   free:9469 free_pcp:231 free_cma:0
  Node 0 active_anon:1455304kB inactive_anon:485132kB active_file:260kB inactive_file:608kB unevictable:0kB isolated(anon):128kB isolated(file):0kB mapped:448kB dirty:0kB writeback:184kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:13641 all_unreclaimable? no
  DMA free:7748kB min:44kB low:56kB high:68kB active_anon:7944kB inactive_anon:104kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:108kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
  lowmem_reserve[]: 0 1952 1952 1952
  DMA32 free:30128kB min:5628kB low:7624kB high:9620kB active_anon:1447360kB inactive_anon:485028kB active_file:260kB inactive_file:608kB unevictable:0kB writepending:184kB present:2080640kB managed:2030132kB mlocked:0kB slab_reclaimable:11112kB slab_unreclaimable:12172kB kernel_stack:2400kB pagetables:7284kB bounce:0kB free_pcp:924kB local_pcp:72kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 0
  DMA: 7*4kB (UE) 3*8kB (UH) 1*16kB (M) 0*32kB 2*64kB (U) 1*128kB (M) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (U) 1*4096kB (H) = 7748kB
  DMA32: 10*4kB (H) 3*8kB (H) 47*16kB (H) 38*32kB (H) 5*64kB (H) 1*128kB (H) 2*256kB (H) 3*512kB (H) 3*1024kB (H) 3*2048kB (H) 4*4096kB (H) = 30128kB
  2775 total pagecache pages
  2536 pages in swap cache
  Swap cache stats: add 206786828, delete 206784292, find 7323106/106686077
  Free swap  = 108744kB
  Total swap = 255996kB
  524158 pages RAM
  0 pages HighMem/MovableOnly
  12648 pages reserved
  0 pages cma reserved
  0 pages hwpoisoned

It's weird to show that zone has enough free memory above min watermark
but OOMed with 4K GFP_KERNEL allocation due to reserved highatomic
pages.  As last resort, try to unreserve highatomic pages again and if
it has moved pages to non-highatmoc free list, retry reclaim once more.

Link: http://lkml.kernel.org/r/1476259429-18279-4-git-send-email-minchan@kernel.org


Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is race between page freeing and unreserved highatomic.

 CPU 0				    CPU 1

    free_hot_cold_page
      mt = get_pfnblock_migratetype
      set_pcppage_migratetype(page, mt)
    				    unreserve_highatomic_pageblock
    				    spin_lock_irqsave(&zone->lock)
    				    move_freepages_block
    				    set_pageblock_migratetype(page)
    				    spin_unlock_irqrestore(&zone->lock)
      free_pcppages_bulk
        __free_one_page(mt) <- mt is stale

By above race, a page on CPU 0 could go non-highorderatomic free list
since the pageblock's type is changed.  By that, unreserve logic of
highorderatomic can decrease reserved count on a same pageblock severak
times and then it will make mismatch between nr_reserved_highatomic and
the number of reserved pageblock.

So, this patch verifies whether the pageblock is highatomic or not and
decrease the count only if the pageblock is highatomic.

Link: http://lkml.kernel.org/r/1476259429-18279-3-git-send-email-minchan@kernel.org


Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "use up highorder free pages before OOM", v3.

I got OOM report from production team with v4.4 kernel.  It had enough
free memory but failed to allocate GFP_KERNEL order-0 page and finally
encountered OOM kill.  It occured during QA process which launches
several apps, switching and so on.  It happned rarely.  IOW, In normal
situation, it was not a problem but if we are unluck so that several
apps uses peak memory at the same time, it can happen.  If we manage to
pass the phase, the system can go working well.

I could reproduce it with my test(memory spike easily.  Look at below.

The reason is free pages(19M) of DMA32 zone are reserved for
HIGHORDERATOMIC and doesn't unreserved before the OOM.

  balloon invoked oom-killer: gfp_mask=0x24280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), order=0, oom_score_adj=0
  balloon cpuset=/ mems_allowed=0
  CPU: 1 PID: 8473 Comm: balloon Tainted: G        W  OE   4.8.0-rc7-00219-g3f74c9559583-dirty #3161
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  Call Trace:
    dump_stack+0x63/0x90
    dump_header+0x5c/0x1ce
    oom_kill_process+0x22e/0x400
    out_of_memory+0x1ac/0x210
    __alloc_pages_nodemask+0x101e/0x1040
    handle_mm_fault+0xa0a/0xbf0
    __do_page_fault+0x1dd/0x4d0
    trace_do_page_fault+0x43/0x130
    do_async_page_fault+0x1a/0xa0
    async_page_fault+0x28/0x30
  Mem-Info:
  active_anon:383949 inactive_anon:106724 isolated_anon:0
   active_file:15 inactive_file:44 isolated_file:0
   unevictable:0 dirty:0 writeback:24 unstable:0
   slab_reclaimable:2483 slab_unreclaimable:3326
   mapped:0 shmem:0 pagetables:1906 bounce:0
   free:6898 free_pcp:291 free_cma:0
  Node 0 active_anon:1535796kB inactive_anon:426896kB active_file:60kB inactive_file:176kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:96kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:1418 all_unreclaimable? no
  DMA free:8188kB min:44kB low:56kB high:68kB active_anon:7648kB inactive_anon:0kB active_file:0kB inactive_file:4kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:20kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
  lowmem_reserve[]: 0 1952 1952 1952
  DMA32 free:19404kB min:5628kB low:7624kB high:9620kB active_anon:1528148kB inactive_anon:426896kB active_file:60kB inactive_file:420kB unevictable:0kB writepending:96kB present:2080640kB managed:2030092kB mlocked:0kB slab_reclaimable:9932kB slab_unreclaimable:13284kB kernel_stack:2496kB pagetables:7624kB bounce:0kB free_pcp:900kB local_pcp:112kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 0
  DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 2*4096kB (H) = 8192kB
  DMA32: 7*4kB (H) 8*8kB (H) 30*16kB (H) 31*32kB (H) 14*64kB (H) 9*128kB (H) 2*256kB (H) 2*512kB (H) 4*1024kB (H) 5*2048kB (H) 0*4096kB = 19484kB
  51131 total pagecache pages
  50795 pages in swap cache
  Swap cache stats: add 3532405601, delete 3532354806, find 124289150/1822712228
  Free swap  = 8kB
  Total swap = 255996kB
  524158 pages RAM
  0 pages HighMem/MovableOnly
  12658 pages reserved
  0 pages cma reserved
  0 pages hwpoisoned

Another example exceeded the limit by the race is

  in:imklog: page allocation failure: order:0, mode:0x2280020(GFP_ATOMIC|__GFP_NOTRACK)
  CPU: 0 PID: 476 Comm: in:imklog Tainted: G            E   4.8.0-rc7-00217-g266ef83c51e5-dirty #3135
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  Call Trace:
    dump_stack+0x63/0x90
    warn_alloc_failed+0xdb/0x130
    __alloc_pages_nodemask+0x4d6/0xdb0
    new_slab+0x339/0x490
    ___slab_alloc.constprop.74+0x367/0x480
    __slab_alloc.constprop.73+0x20/0x40
    __kmalloc+0x1a4/0x1e0
    alloc_indirect.isra.14+0x1d/0x50
    virtqueue_add_sgs+0x1c4/0x470
    __virtblk_add_req+0xae/0x1f0
    virtio_queue_rq+0x12d/0x290
    __blk_mq_run_hw_queue+0x239/0x370
    blk_mq_run_hw_queue+0x8f/0xb0
    blk_mq_insert_requests+0x18c/0x1a0
    blk_mq_flush_plug_list+0x125/0x140
    blk_flush_plug_list+0xc7/0x220
    blk_finish_plug+0x2c/0x40
    __do_page_cache_readahead+0x196/0x230
    filemap_fault+0x448/0x4f0
    ext4_filemap_fault+0x36/0x50
    __do_fault+0x75/0x140
    handle_mm_fault+0x84d/0xbe0
    __do_page_fault+0x1dd/0x4d0
    trace_do_page_fault+0x43/0x130
    do_async_page_fault+0x1a/0xa0
    async_page_fault+0x28/0x30
  Mem-Info:
  active_anon:363826 inactive_anon:121283 isolated_anon:32
   active_file:65 inactive_file:152 isolated_file:0
   unevictable:0 dirty:0 writeback:46 unstable:0
   slab_reclaimable:2778 slab_unreclaimable:3070
   mapped:112 shmem:0 pagetables:1822 bounce:0
   free:9469 free_pcp:231 free_cma:0
  Node 0 active_anon:1455304kB inactive_anon:485132kB active_file:260kB inactive_file:608kB unevictable:0kB isolated(anon):128kB isolated(file):0kB mapped:448kB dirty:0kB writeback:184kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:13641 all_unreclaimable? no
  DMA free:7748kB min:44kB low:56kB high:68kB active_anon:7944kB inactive_anon:104kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:108kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
  lowmem_reserve[]: 0 1952 1952 1952
  DMA32 free:30128kB min:5628kB low:7624kB high:9620kB active_anon:1447360kB inactive_anon:485028kB active_file:260kB inactive_file:608kB unevictable:0kB writepending:184kB present:2080640kB managed:2030132kB mlocked:0kB slab_reclaimable:11112kB slab_unreclaimable:12172kB kernel_stack:2400kB pagetables:7284kB bounce:0kB free_pcp:924kB local_pcp:72kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 0
  DMA: 7*4kB (UE) 3*8kB (UH) 1*16kB (M) 0*32kB 2*64kB (U) 1*128kB (M) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (U) 1*4096kB (H) = 7748kB
  DMA32: 10*4kB (H) 3*8kB (H) 47*16kB (H) 38*32kB (H) 5*64kB (H) 1*128kB (H) 2*256kB (H) 3*512kB (H) 3*1024kB (H) 3*2048kB (H) 4*4096kB (H) = 30128kB
  2775 total pagecache pages
  2536 pages in swap cache
  Swap cache stats: add 206786828, delete 206784292, find 7323106/106686077
  Free swap  = 108744kB
  Total swap = 255996kB
  524158 pages RAM
  0 pages HighMem/MovableOnly
  12648 pages reserved
  0 pages cma reserved
  0 pages hwpoisoned

During the investigation, I found some problems with highatomic so this
patch aims to solve the problems and the final goal is to unreserve
every highatomic free pages before the OOM kill.

This patch (of 4):

In page freeing path, migratetype is racy so that a highorderatomic page
could free into non-highorderatomic free list.  If that page is
allocated, VM can change the pageblock from higorderatomic to something.
In that case, highatomic pageblock accounting is broken so it doesn't
work(e.g., VM cannot reserve highorderatomic pageblocks any more
although it doesn't reach 1% limit).

So, this patch prohibits the changing from highatomic to other type.
It's no problem because MIGRATE_HIGHATOMIC is not listed in fallback
array so stealing will only happen due to unexpected races which is
really rare.  Also, such prohibiting keeps highatomic pageblock more
longer so it would be better for highorderatomic page allocation.

Link: http://lkml.kernel.org/r/1476259429-18279-2-git-send-email-minchan@kernel.org


Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sangseok Lee <sangseok.lee@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kmemleak.txt was moved to Documentation/dev-tools/kmemleak.rst,
this fixes the reference to the new location.

Link: http://lkml.kernel.org/r/1476544946-18804-1-git-send-email-andreas.platschek@opentech.at


Signed-off-by: Andreas Platschek <andreas.platschek@opentech.at>
Acked-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>

No functional change by this patch.

Link: http://lkml.kernel.org/r/20161018090234.22574-1-aneesh.kumar@linux.vnet.ibm.com


Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We cannot use the pte value used in set_pte_at for pte_same comparison,
because archs like ppc64, filter/add new pte flag in set_pte_at.
Instead fetch the pte value inside hugetlb_cow.  We are comparing pte
value to make sure the pte didn't change since we dropped the page table
lock.  hugetlb_cow get called with page table lock held, and we can take
a copy of the pte value before we drop the page table lock.

With hugetlbfs, we optimize the MAP_PRIVATE write fault path with no
previous mapping (huge_pte_none entries), by forcing a cow in the fault
path.  This avoid take an addition fault to covert a read-only mapping
to read/write.  Here we were comparing a recently instantiated pte (via
set_pte_at) to the pte values from linux page table.  As explained above
on ppc64 such pte_same check returned wrong result, resulting in us
taking an additional fault on ppc64.

Fixes: 6a119eae ("powerpc/mm: Add a _PAGE_PTE bit")
Link: http://lkml.kernel.org/r/20161018154245.18023-1-aneesh.kumar@linux.vnet.ibm.com


Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
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>

Make vma_permits_fault() static as it is only used in mm/gup.c

This fixes a sparse warning.

Link: http://lkml.kernel.org/r/20161017122353.31598-1-tklauser@distanz.ch


Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Our system uses significantly more slab memory with memcg enabled with
the latest kernel.  With 3.10 kernel, slab uses 2G memory, while with
4.6 kernel, 6G memory is used.  The shrinker has problem.  Let's see we
have two memcg for one shrinker.  In do_shrink_slab:

1. Check cg1.  nr_deferred = 0, assume total_scan = 700.  batch size
   is 1024, then no memory is freed.  nr_deferred = 700

2. Check cg2.  nr_deferred = 700.  Assume freeable = 20, then
   total_scan = 10 or 40.  Let's assume it's 10.  No memory is freed.
   nr_deferred = 10.

The deferred share of cg1 is lost in this case.  kswapd will free no
memory even run above steps again and again.

The fix makes sure one memcg's deferred share isn't lost.

Link: http://lkml.kernel.org/r/2414be961b5d25892060315fbb56bb19d81d0c07.1476227351.git.shli@fb.com


Signed-off-by: Shaohua Li <shli@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We had some problems with pages getting unmapped in single threaded
affinitized processes.  It was tracked down to NUMA scanning.

In this case it doesn't make any sense to unmap pages if the process is
single threaded and the page is already on the node the process is
running on.

Add a check for this case into the numa protection code, and skip
unmapping if true.

In theory the process could be migrated later, but we will eventually
rescan and unmap and migrate then.

In theory this could be made more fancy: remembering this state per
process or even whole mm.  However that would need extra tracking and be
more complicated, and the simple check seems to work fine so far.

[ak@linux.intel.com: v3: Minor updates from Mel. Change code layout]
  Link: http://lkml.kernel.org/r/1476382117-5440-1-git-send-email-andi@firstfloor.org
Link: http://lkml.kernel.org/r/1476288949-20970-1-git-send-email-andi@firstfloor.org


Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Rather than tracking the number of active slabs for each node, track the
total number of slabs.  This is a minor improvement that avoids active
slab tracking when a slab goes from free to partial or partial to free.

For slab debugging, this also removes an explicit free count since it
can easily be inferred by the difference in number of total objects and
number of active objects.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1612042020110.115755@chino.kir.corp.google.com


Signed-off-by: David Rientjes <rientjes@google.com>
Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Reading /proc/slabinfo or monitoring slabtop(1) can become very
expensive if there are many slab caches and if there are very lengthy
per-node partial and/or free lists.

Commit 07a63c41 ("mm/slab: improve performance of gathering slabinfo
stats") addressed the per-node full lists which showed a significant
improvement when no objects were freed.  This patch has the same
motivation and optimizes the remainder of the usecases where there are
very lengthy partial and free lists.

This patch maintains per-node active_slabs (full and partial) and
free_slabs rather than iterating the lists at runtime when reading
/proc/slabinfo.

When allocating 100GB of slab from a test cache where every slab page is
on the partial list, reading /proc/slabinfo (includes all other slab
caches on the system) takes ~247ms on average with 48 samples.

As a result of this patch, the same read takes ~0.856ms on average.

[rientjes@google.com: changelog]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1611081505240.13403@chino.kir.corp.google.com


Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
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>

Verify that kmem_create_cache flags are not allocator specific.  It is
done before removing flags that are not available with the current
configuration.

The current kmem_cache_create removes incorrect flags but do not
validate the callers are using them right.  This change will ensure that
callers are not trying to create caches with flags that won't be used
because allocator specific.

Link: http://lkml.kernel.org/r/1478553075-120242-2-git-send-email-thgarnie@google.com


Signed-off-by: Thomas Garnier <thgarnie@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@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>

The slub allocator gives us some incorrect warnings when
CONFIG_PROFILE_ANNOTATED_BRANCHES is set, as the unlikely() macro
prevents it from seeing that the return code matches what it was before:

  mm/slub.c: In function `kmem_cache_free_bulk':
  mm/slub.c:262:23: error: `df.s' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  mm/slub.c:2943:3: error: `df.cnt' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  mm/slub.c:2933:4470: error: `df.freelist' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  mm/slub.c:2943:3: error: `df.tail' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I have not been able to come up with a perfect way for dealing with
this, the three options I see are:

 - add a bogus initialization, which would increase the runtime overhead
 - replace unlikely() with unlikely_notrace()
 - remove the unlikely() annotation completely

I checked the object code for a typical x86 configuration and the last
two cases produce the same result, so I went for the last one, which is
the simplest.

Link: http://lkml.kernel.org/r/20161024155704.3114445-1-arnd@arndb.de


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

synchronize_sched() is a heavy operation and calling it per each cache
owned by a memory cgroup being destroyed may take quite some time.  What
is worse, it's currently called under the slab_mutex, stalling all works
doing cache creation/destruction.

Actually, there isn't much point in calling synchronize_sched() for each
cache - it's enough to call it just once - after setting cpu_partial for
all caches and before shrinking them.  This way, we can also move it out
of the slab_mutex, which we have to hold for iterating over the slab
cache list.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=172991
Link: http://lkml.kernel.org/r/0a10d71ecae3db00fb4421bcd3f82bcc911f4be4.1475329751.git.vdavydov.dev@gmail.com


Signed-off-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reported-by: Doug Smythies <dsmythies@telus.net>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Creating a lot of cgroups at the same time might stall all worker
threads with kmem cache creation works, because kmem cache creation is
done with the slab_mutex held.  The problem was amplified by commits
801faf0d ("mm/slab: lockless decision to grow cache") in case of
SLAB and 81ae6d03 ("mm/slub.c: replace kick_all_cpus_sync() with
synchronize_sched() in kmem_cache_shrink()") in case of SLUB, which
increased the maximal time the slab_mutex can be held.

To prevent that from happening, let's use a special ordered single
threaded workqueue for kmem cache creation.  This shouldn't introduce
any functional changes regarding how kmem caches are created, as the
work function holds the global slab_mutex during its whole runtime
anyway, making it impossible to run more than one work at a time.  By
using a single threaded workqueue, we just avoid creating a thread per
each work.  Ordering is required to avoid a situation when a cgroup's
work is put off indefinitely because there are other cgroups to serve,
in other words to guarantee fairness.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=172981
Link: http://lkml.kernel.org/r/20161004131417.GC1862@esperanza


Signed-off-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reported-by: Doug Smythies <dsmythies@telus.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

CURRENT_TIME is not y2038 safe.

Use y2038 safe ktime_get_real_seconds() here for timestamps.  struct
heartbeat_block's hb_seq and deletetion time are already 64 bits wide
and accommodate times beyond y2038.

Also use y2038 safe ktime_get_real_ts64() for on disk inode timestamps.
These are also wide enough to accommodate time64_t.

Link: http://lkml.kernel.org/r/1475365298-29236-1-git-send-email-deepa.kernel@gmail.com


Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

struct timespec is not y2038 safe.  Use time64_t which is y2038 safe to
represent orphan scan times.  time64_t is sufficient here as only the
seconds delta times are relevant.

Also use appropriate time functions that return time in time64_t format.
Time functions now return monotonic time instead of real time as only
delta scan times are relevant and these values are not persistent across
reboots.

The format string for the debug print is still using long as this is
only the time elapsed since the last scan and long is sufficient to
represent this value.

Link: http://lkml.kernel.org/r/1475365138-20567-1-git-send-email-deepa.kernel@gmail.com


Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In ocfs2_lock_refcount_tree, if ocfs2_read_refcount_block() returns an
error, we do ocfs2_refcount_tree_put twice (once in
ocfs2_unlock_refcount_tree and once outside it), thereby reducing the
refcount of the refcount tree twice, but we dont delete the tree in this
case.  This will make refcnt of the tree = 0 and the
ocfs2_refcount_tree_put will eventually call ocfs2_mark_lockres_freeing,
setting OCFS2_LOCK_FREEING for the refcount_tree->rf_lockres.

The error returned by ocfs2_read_refcount_block is propagated all the
way back and for next iteration of write, ocfs2_lock_refcount_tree gets
the same tree back from ocfs2_get_refcount_tree because we havent
deleted the tree.  Now we have the same tree, but OCFS2_LOCK_FREEING is
set for rf_lockres and eventually, when _ocfs2_lock_refcount_tree is
called in this iteration, BUG_ON( __ocfs2_cluster_lock:1395 ERROR:
Cluster lock called on freeing lockres T00000000000000000386019775b08d!
flags 0x81) is triggerred.

Call stack:

  (loop16,11155,0):ocfs2_lock_refcount_tree:482 ERROR: status = -5
  (loop16,11155,0):ocfs2_refcount_cow_hunk:3497 ERROR: status = -5
  (loop16,11155,0):ocfs2_refcount_cow:3560 ERROR: status = -5
  (loop16,11155,0):ocfs2_prepare_inode_for_refcount:2111 ERROR: status = -5
  (loop16,11155,0):ocfs2_prepare_inode_for_write:2190 ERROR: status = -5
  (loop16,11155,0):ocfs2_file_write_iter:2331 ERROR: status = -5
  (loop16,11155,0):__ocfs2_cluster_lock:1395 ERROR: bug expression:
  lockres->l_flags & OCFS2_LOCK_FREEING

  (loop16,11155,0):__ocfs2_cluster_lock:1395 ERROR: Cluster lock called on
  freeing lockres T00000000000000000386019775b08d! flags 0x81

  kernel BUG at fs/ocfs2/dlmglue.c:1395!

  invalid opcode: 0000 [#1] SMP  CPU 0
  Modules linked in: tun ocfs2 jbd2 xen_blkback xen_netback xen_gntdev .. sd_mod crc_t10dif ext3 jbd mbcache
  RIP: __ocfs2_cluster_lock+0x31c/0x740 [ocfs2]
  RSP: e02b:ffff88017c0138a0  EFLAGS: 00010086
  Process loop16 (pid: 11155, threadinfo ffff88017c010000, task ffff8801b5374300)
  Call Trace:
     ocfs2_refcount_lock+0xae/0x130 [ocfs2]
     __ocfs2_lock_refcount_tree+0x29/0xe0 [ocfs2]
     ocfs2_lock_refcount_tree+0xdd/0x320 [ocfs2]
     ocfs2_refcount_cow_hunk+0x1cb/0x440 [ocfs2]
     ocfs2_refcount_cow+0xa9/0x1d0 [ocfs2]
     ocfs2_prepare_inode_for_refcount+0x115/0x200 [ocfs2]
     ocfs2_prepare_inode_for_write+0x33b/0x470 [ocfs2]
     ocfs2_file_write_iter+0x220/0x8c0 [ocfs2]
     aio_write_iter+0x2e/0x30

Fix this by avoiding the second call to ocfs2_refcount_tree_put()

Link: http://lkml.kernel.org/r/1473984404-32011-1-git-send-email-ashish.samant@oracle.com


Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Eric Ren <zren@suse.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

'page' parameter in ocfs2_write_end_nolock() is never used.

Link: http://lkml.kernel.org/r/582FD91A.5000902@huawei.com


Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When 'dispatch_assert' is set, 'response' must be DLM_MASTER_RESP_YES,
and 'res' won't be null, so execution can't reach these two branch.

Link: http://lkml.kernel.org/r/58174C91.3040004@huawei.com


Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Joseph Qi Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The variable `set_maybe' is redundant when the mle has been found in the
map.  So it is ok to set the node_idx into mle's maybe_map directly.

Link: http://lkml.kernel.org/r/71604351584F6A4EBAE558C676F37CA4A3D490DD@H3CMLB12-EX.srv.huawei-3com.com


Signed-off-by: Guozhonghua <guozhonghua@h3c.com>
Reviewed-by: Mark Fasheh <mfasheh@versity.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The value of 'stage' must be between 1 and 2, so the switch can't reach
the default case.

Link: http://lkml.kernel.org/r/57FB5EB2.7050002@huawei.com


Signed-off-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If request_irq() fails it passes the error to the caller.  The caller
now checks it and jumps to the common error path on failure.

Link: http://lkml.kernel.org/r/1474237304-897-3-git-send-email-sudipm.mukherjee@gmail.com


Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Use a common error path for the failure.

Link: http://lkml.kernel.org/r/1474237304-897-2-git-send-email-sudipm.mukherjee@gmail.com


Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

While building m32r allmodconfig we were getting warning:

  drivers/pcmcia/m32r_pcc.c:331:2: warning: ignoring return value of 'request_irq', declared with attribute warn_unused_result

request_irq() can fail and we should always be checking the result from
it. Check the result and return it to the caller.

Link: http://lkml.kernel.org/r/1474237304-897-1-git-send-email-sudipm.mukherjee@gmail.com


Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

While building m32r defconfig we got warnings:

  arch/m32r/platforms/m32700ut/setup.c:249:24: warning: 'm32700ut_lcdpld_irq_type' defined but not used [-Wunused-variable]

m32700ut_lcdpld_irq_type is only used when CONFIG_USB is enabled.
Modify the code to declare the related variables and functions only when
CONFIG_USB is enabled.

Link: http://lkml.kernel.org/r/1479244406-7507-1-git-send-email-sudipm.mukherjee@gmail.com


Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Some builds of m32r were failing as it tried to build few drivers which
needed dma but m32r is not having dma support.  Objections were raised
when it was tried to make those drivers depend on HAS_DMA.  So the next
best thing is to add dma support to m32r.  dma_noop is a very simple dma
with 1:1 memory mapping.

Link: http://lkml.kernel.org/r/1475949198-31623-1-git-send-email-sudipm.mukherjee@gmail.com


Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When SUBARCH is "omap1" or "omap2", plat-omap/ directory must be
indexed.  Handle this special case properly.

While at it, check if mach- directory exists at all.

Link: http://lkml.kernel.org/r/20161202122148.15001-1-joe.skb7@gmail.com


Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Michal Marek <mmarek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Every often used regex is better be compiled in Python.

Speedup is about ~9.8% (whee!)

    $ perf stat -r 16 taskset -c 15 ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux >/dev/null
    7.091202853 seconds time elapsed                         ( +-  0.15% )

    +re.compile
    6.397564973 seconds time elapsed                         ( +-  0.34% )

Link: http://lkml.kernel.org/r/20161119004417.GB1200@avx2


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

readlines() conses whole list before doing anything which is slower for
big object files.  Use per line iterator.

Speed up is ~2% on "allyesconfig" type of kernel.

    $ perf stat -r 16 taskset -c 15 ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux >/dev/null
	...

  Before:  7.247708646 seconds time elapsed                ( +-  0.28% )
  After:   7.091202853 seconds time elapsed                ( +-  0.15% )

Link: http://lkml.kernel.org/r/20161119004143.GA1200@avx2


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This limitation came with the reason to remove "another way for
malicious code to obscure a compromised program and masquerade as a
benign process" by allowing "security-concious program can use this
prctl once during its early initialization to ensure the prctl cannot
later be abused for this purpose":

    http://marc.info/?l=linux-kernel&m=133160684517468&w=2

This explanation doesn't look sufficient.  The only thing "exe" link is
indicating is the file, used to execve, which is basically nothing and
not reliable immediately after process has returned from execve system
call.

Moreover, to use this feture, all the mappings to previous exe file have
to be unmapped and all the new exe file permissions must be satisfied.

Which means, that changing exe link is very similar to calling execve on
the binary.

The need to remove this limitations comes from migration of NFS mount
point, which is not accessible during restore and replaced by other file
system.  Because of this exe link has to be changed twice.

[akpm@linux-foundation.org: fix up comment]
Link: http://lkml.kernel.org/r/20160927153755.9337.69650.stgit@localhost.localdomain


Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When commit fbae2d44 ("kthread: add kthread_create_worker*()")
introduced some kthread_create_...() functions which were taking
printf-like parametter, it introduced __printf attributes to some
functions (e.g.  kthread_create_worker()).  Nevertheless some new
functions were forgotten (they have been detected thanks to
-Wmissing-format-attribute warning flag).

Add the missing __printf attributes to the newly-introduced functions in
order to detect formatting issues at build-time with -Wformat flag.

Link: http://lkml.kernel.org/r/20161126193543.22672-1-nicolas.iooss_linux@m4x.org


Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull x86 RAS updates from Ingo Molnar:
 "The main changes in this development cycle were:

   - more AMD northbridge support work, mostly in preparation for Fam17h
     CPUs (Yazen Ghannam, Borislav Petkov)

   - cleanups/refactorings and fixes (Borislav Petkov, Tony Luck,
     Yinghai Lu)"

* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Include the PPIN in MCE records when available
  x86/mce/AMD: Add system physical address translation for AMD Fam17h
  x86/amd_nb: Add SMN and Indirect Data Fabric access for AMD Fam17h
  x86/amd_nb: Add Fam17h Data Fabric as "Northbridge"
  x86/amd_nb: Make all exports EXPORT_SYMBOL_GPL
  x86/amd_nb: Make amd_northbridges internal to amd_nb.c
  x86/mce/AMD: Reset Threshold Limit after logging error
  x86/mce/AMD: Fix HWID_MCATYPE calculation by grouping arguments
  x86/MCE: Correct TSC timestamping of error records
  x86/RAS: Hide SMCA bank names
  x86/RAS: Rename smca_bank_names to smca_names
  x86/RAS: Simplify SMCA HWID descriptor struct
  x86/RAS: Simplify SMCA bank descriptor struct
  x86/MCE: Dump MCE to dmesg if no consumers
  x86/RAS: Add TSC timestamp to the injected MCE
  x86/MCE: Do not look at panic_on_oops in the severity grading

Pull hotplug API fix from Ingo Molnar:
 "Late breaking fix from the v4.9 cycle: fix a hotplug register/
  unregister notifier API asymmetry bug that can cause kernel warnings
  (and worse) with certain Kconfig combinations"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hotplug: Make register and unregister notifier API symmetric

Pull scheduler updates from Ingo Molnar:
 "The main scheduler changes in this cycle were:

   - support Intel Turbo Boost Max Technology 3.0 (TBM3) by introducig a
     notion of 'better cores', which the scheduler will prefer to
     schedule single threaded workloads on. (Tim Chen, Srinivas
     Pandruvada)

   - enhance the handling of asymmetric capacity CPUs further (Morten
     Rasmussen)

   - improve/fix load handling when moving tasks between task groups
     (Vincent Guittot)

   - simplify and clean up the cputime code (Stanislaw Gruszka)

   - improve mass fork()ed task spread a.k.a. hackbench speedup (Vincent
     Guittot)

   - make struct kthread kmalloc()ed and related fixes (Oleg Nesterov)

   - add uaccess atomicity debugging (when using access_ok() in the
     wrong context), under CONFIG_DEBUG_ATOMIC_SLEEP=y (Peter Zijlstra)

   - implement various fixes, cleanups and other enhancements (Daniel
     Bristot de Oliveira, Martin Schwidefsky, Rafael J. Wysocki)"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
  sched/core: Use load_avg for selecting idlest group
  sched/core: Fix find_idlest_group() for fork
  kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker()
  kthread: Don't use to_live_kthread() in kthread_[un]park()
  kthread: Don't use to_live_kthread() in kthread_stop()
  Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function"
  kthread: Make struct kthread kmalloc'ed
  x86/uaccess, sched/preempt: Verify access_ok() context
  sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable
  sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO
  x86/sched: Use #include <linux/mutex.h> instead of #include <asm/mutex.h>
  cpufreq/intel_pstate: Use CPPC to get max performance
  acpi/bus: Set _OSC for diverse core support
  acpi/bus: Enable HWP CPPC objects
  x86/sched: Add SD_ASYM_PACKING flags to x86 ITMT CPU
  x86/sysctl: Add sysctl for ITMT scheduling feature
  x86: Enable Intel Turbo Boost Max Technology 3.0
  x86/topology: Define x86's arch_update_cpu_topology
  sched: Extend scheduler's asym packing
  sched/fair: Clean up the tunable parameter definitions
  ...

Pull perf updates from Ingo Molnar:
 "This update is pretty big and almost exclusively includes tooling
  changes, because v4.9's LTS status forced to completion most of the
  pending kernel side hardware enablement work and because we tried to
  freeze core perf work a bit to give a time window for the fuzzing
  efforts.

  The diff is large mostly due to the JSON hardware event tables added
  for Intel and Power8 CPUs. This was a popular feature request from
  people working close to hardware and from the HPC community.

  Tree size is big because this added the CPU event tables for over a
  decade of Intel CPUs. Future changes for a CPU vendor alrady support
  should be much smaller, as events for new models are added. The new
  events are listed in 'perf list', for the CPU model the tool is
  running on. If you find an interesting event it can be used as-is:

      $ perf stat -a -e l2_lines_out.pf_clean sleep 1

      Performance counter stats for 'system wide':

            7,860,403      l2_lines_out.pf_clean

           1.000624918 seconds time elapsed

  The event lists can be searched the usual 'perf list' fashion for
  (case insensitive) substrings as well:

      $ perf list l2_lines_out

      List of pre-defined events (to be used in -e):

      cache:
        l2_lines_out.demand_clean
             [Clean L2 cache lines evicted by demand]
        l2_lines_out.demand_dirty
             [Dirty L2 cache lines evicted by demand]
        l2_lines_out.dirty_all
             [Dirty L2 cache lines filling the L2]
        l2_lines_out.pf_clean
             [Clean L2 cache lines evicted by L2 prefetch]
        l2_lines_out.pf_dirty
             [Dirty L2 cache lines evicted by L2 prefetch]

  etc.

  There's a few high level categories as well that can be listed:
  'cache', 'floating point', 'frontend', 'memory', 'pipeline', 'virtual
  memory'.

  Existing generic events and workflows should work as-is.

  The only kernel side change is a late breaking fix for an older
  regression, related to Intel BTS, LBR and PT feature interaction.

  On the tooling side there are three new tools / major features:

   - The new 'perf c2c' tool provides means for Shared Data C2C/HITM
     analysis.

     This allows you to track down cacheline contention. The tool is
     based on x86's load latency and precise store facility events
     provided by Intel CPUs.

     It was tested by Joe Mario and has proven to be useful, finding
     some cacheline contentions. Joe also wrote a blog about c2c tool
     with examples:

        https://joemario.github.io/blog/2016/09/01/c2c-blog/

     excerpt of the content on this site:

         At a high level, “perf c2c” will show you:

          * The cachelines where false sharing was detected.
          * The readers and writers to those cachelines, and the offsets where those accesses occurred.
          * The pid, tid, instruction addr, function name, binary object name for those readers and writers.
          * The source file and line number for each reader and writer.
          * The average load latency for the loads to those cachelines.
          * Which numa nodes the samples a cacheline came from and which CPUs were involved.

         Using perf c2c is similar to using the Linux perf tool today.
         First collect data with “perf c2c record”, then generate a
         report output with “perf c2c report”

     There one finds extensive details on using the tool, with tips on
     reducing the volume of samples while still capturing enough to do
     its job. (Dick Fowles, Joe Mario, Don Zickus, Jiri Olsa)

   - The new 'perf sched timehist' tool provides tailored analysis of
     scheduling events.

     Example usage:

          perf sched record -- sleep 1
          perf sched timehist

     By default it shows the individual schedule events, including the
     wait time (time between sched-out and next sched-in events for the
     task), the task scheduling delay (time between wakeup and actually
     running) and run time for the task:

            time    cpu  task name         wait time  sch delay  run time
                         [tid/pid]            (msec)     (msec)    (msec)
        -------- ------  ----------------  ---------  ---------  --------
        1.874569 [0011]  gcc[31949]            0.014      0.000     1.148
        1.874591 [0010]  gcc[31951]            0.000      0.000     0.024
        1.874603 [0010]  migration/10[59]      3.350      0.004     0.011
        1.874604 [0011]  <idle>                1.148      0.000     0.035
        1.874723 [0005]  <idle>                0.016      0.000     1.383
        1.874746 [0005]  gcc[31949]            0.153      0.078     0.022
      ...

     Times are in msec.usec. (David Ahern, Namhyung Kim)

   - Add CPU vendor hardware event tables:

     Add JSON files with vendor event naming for Intel and Power8
     processors, allowing users of tools like oprofile to keep using the
     event names they are used to, as well as people reading vendor
     documentation, where such naming is used. (Andi Kleen, Sukadev
     Bhattiprolu)

     You should see all the new events with 'perf list' and you should
     be able to search them, for example 'perf list miss' will list all
     the myriads of miss events.

  Other tooling features added were:

   - Cross-arch annotation support:

     o Improve ARM support in the annotation code, affecting 'perf
       annotate', 'perf report' and live annotation in 'perf top' (Kim
       Phillips)

     o Initial support for PowerPC in the annotation code (Ravi
       Bangoria)

     o Support AArch64 in the 'annotate' code, native/local and
       cross-arch/remote (Kim Phillips)

   - Allow considering just events in a given time interval, via the
     '--time start.s.ms,end.s.ms' command line, added to 'perf kmem',
     'perf report', 'perf sched timehist' and 'perf script' (David
     Ahern)

   - Add option to stop printing a callchain at one of a given group of
     symbol names (David Ahern)

   - Track memory freed in 'perf kmem stat' (David Ahern)

   - Allow querying and setting .perfconfig variables (Taeung Song)

   - Show branch information in callchains (predicted, TSX aborts, loop
     iteractions, etc) (Jin Yao)

   - Dynamicly change verbosity level by pressing 'V' in the 'perf
     top/report' hists TUI browser (Alexis Berlemont)

   - Implement 'perf trace --delay' in the same fashion as in 'perf
     record --delay', to skip sampling workload initialization events
     (Alexis Berlemont)

   - Make vendor named events case insensitive in 'perf list', i.e.
     'perf list LONGEST_LAT' works just the same as 'perf list
     longest_lat' (Andi Kleen)

   - Add unwinding support for jitdump (Stefano Sanfilippo)

  Tooling infrastructure changes:

   - Support linking perf with clang and LLVM libraries, initially
     statically, but this limitation will be lifted and shared
     libraries, when available, will be preferred to the static build,
     that should, as with other features, be enabled explicitly (Wang
     Nan)

   - Add initial support (and perf test entry) for tooling hooks,
     starting with 'record_start' and 'record_end', that will have as
     its initial user the eBPF infrastructure, where perf_ prefixed
     functions will be JITed and run when such hooks are called (Wang
     Nan)

   - Implement assorted libbpf improvements (Wang Nan)"

  ... and lots of other changes, features, cleanups and refactorings I
  did not list, see the shortlog and the git log for details"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (220 commits)
  perf/x86: Fix exclusion of BTS and LBR for Goldmont
  perf tools: Explicitly document that --children is enabled by default
  perf sched timehist: Cleanup idle_max_cpu handling
  perf sched timehist: Handle zero sample->tid properly
  perf callchain: Introduce callchain_cursor__copy()
  perf sched: Cleanup option processing
  perf sched timehist: Improve error message when analyzing wrong file
  perf tools: Move perf build related variables under non fixdep leg
  perf tools: Force fixdep compilation at the start of the build
  perf tools: Move PERF-VERSION-FILE target into rules area
  perf build: Check LLVM version in feature check
  perf annotate: Show raw form for jump instruction with indirect target
  perf tools: Add non config targets
  perf tools: Cleanup build directory before each test
  perf tools: Move python/perf.so target into rules area
  perf tools: Move install-gtk target into rules area
  tools build: Move tabs to spaces where suitable
  tools build: Make the .cmd file more readable
  perf clang: Compile BPF script using builtin clang support
  perf clang: Support compile IR to BPF object and add testcase
  ...

Pull mm/PAT cleanup from Ingo Molnar:
 "A single cleanup for a generic interface that was originally
  introduced for PAT"

* 'mm-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pat, mm: Make track_pfn_insert() return void

Pull locking updates from Ingo Molnar:
 "The tree got pretty big in this development cycle, but the net effect
  is pretty good:

    115 files changed, 673 insertions(+), 1522 deletions(-)

  The main changes were:

   - Rework and generalize the mutex code to remove per arch mutex
     primitives. (Peter Zijlstra)

   - Add vCPU preemption support: add an interface to query the
     preemption status of vCPUs and use it in locking primitives - this
     optimizes paravirt performance. (Pan Xinhui, Juergen Gross,
     Christian Borntraeger)

   - Introduce cpu_relax_yield() and remov cpu_relax_lowlatency() to
     clean up and improve the s390 lock yielding machinery and its core
     kernel impact. (Christian Borntraeger)

   - Micro-optimize mutexes some more. (Waiman Long)

   - Reluctantly add the to-be-deprecated mutex_trylock_recursive()
     interface on a temporary basis, to give the DRM code more time to
     get rid of its locking hacks. Any other users will be NAK-ed on
     sight. (We turned off the deprecation warning for the time being to
     not pollute the build log.) (Peter Zijlstra)

   - Improve the rtmutex code a bit, in light of recent long lived
     bugs/races. (Thomas Gleixner)

   - Misc fixes, cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  x86/paravirt: Fix bool return type for PVOP_CALL()
  x86/paravirt: Fix native_patch()
  locking/ww_mutex: Use relaxed atomics
  locking/rtmutex: Explain locking rules for rt_mutex_proxy_unlock()/init_proxy_locked()
  locking/rtmutex: Get rid of RT_MUTEX_OWNER_MASKALL
  x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()
  locking/mutex: Break out of expensive busy-loop on {mutex,rwsem}_spin_on_owner() when owner vCPU is preempted
  locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock()
  Documentation/virtual/kvm: Support the vCPU preemption check
  x86/xen: Support the vCPU preemption check
  x86/kvm: Support the vCPU preemption check
  x86/kvm: Support the vCPU preemption check
  kvm: Introduce kvm_write_guest_offset_cached()
  locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests
  locking/spinlocks, s390: Implement vcpu_is_preempted(cpu)
  locking/core, powerpc: Implement vcpu_is_preempted(cpu)
  sched/core: Introduce the vcpu_is_preempted(cpu) interface
  sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q
  locking/core: Provide common cpu_relax_yield() definition
  locking/mutex: Don't mark mutex_trylock_recursive() as deprecated, temporarily
  ...

Pull EFI updates from Ingo Molnar:
 "The main changes in this development cycle were:

   - Implement EFI dev path parser and other changes to fully support
     thunderbolt devices on Apple Macbooks (Lukas Wunner)

   - Add RNG seeding via the EFI stub, on ARM/arm64 (Ard Biesheuvel)

   - Expose EFI framebuffer configuration to user-space, to improve
     tooling (Peter Jones)

   - Misc fixes and cleanups (Ivan Hu, Wei Yongjun, Yisheng Xie, Dan
     Carpenter, Roy Franz)"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/libstub: Make efi_random_alloc() allocate below 4 GB on 32-bit
  thunderbolt: Compile on x86 only
  thunderbolt, efi: Fix Kconfig dependencies harder
  thunderbolt, efi: Fix Kconfig dependencies
  thunderbolt: Use Device ROM retrieved from EFI
  x86/efi: Retrieve and assign Apple device properties
  efi: Allow bitness-agnostic protocol calls
  efi: Add device path parser
  efi/arm*/libstub: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table
  efi/libstub: Add random.c to ARM build
  efi: Add support for seeding the RNG from a UEFI config table
  MAINTAINERS: Add ARM and arm64 EFI specific files to EFI subsystem
  efi/libstub: Fix allocation size calculations
  efi/efivar_ssdt_load: Don't return success on allocation failure
  efifb: Show framebuffer layout as device attributes
  efi/efi_test: Use memdup_user() as a cleanup
  efi/efi_test: Fix uninitialized variable 'rv'
  efi/efi_test: Fix uninitialized variable 'datasize'
  efi/arm*: Fix efi_init() error handling
  efi: Remove unused include of <linux/version.h>