user/sven/linux.git/mm, branch v4.16.1

mm/kmemleak.c: wait for scan completion before disabling free

2018-03-28T23:42:05Z

A crash is observed when kmemleak_scan accesses the object->pointer, likely due to the following race. TASK A TASK B TASK C kmemleak_write (with "scan" and NOT "scan=on") kmemleak_scan() create_object kmem_cache_alloc fails kmemleak_disable kmemleak_do_cleanup kmemleak_free_enabled = 0 kfree kmemleak_free bails out (kmemleak_free_enabled is 0) slub frees object->pointer update_checksum crash - object->pointer freed (DEBUG_PAGEALLOC) kmemleak_do_cleanup waits for the scan thread to complete, but not for direct call to kmemleak_scan via kmemleak_write. So add a wait for kmemleak_scan completion before disabling kmemleak_free, and while at it fix the comment on stop_scan_thread. [vinmenon@codeaurora.org: fix stop_scan_thread comment] Link: http://lkml.kernel.org/r/1522219972-22809-1-git-send-email-vinmenon@codeaurora.org Link: http://lkml.kernel.org/r/1522063429-18992-1-git-send-email-vinmenon@codeaurora.org Signed-off-by: Vinayak Menon Reviewed-by: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memcontrol.c: fix parameter description mismatch

2018-03-28T23:42:05Z

There are a couple of places where parameter description and function name do not match the actual code. Fix it. Link: http://lkml.kernel.org/r/1520843448-17347-1-git-send-email-honglei.wang@oracle.com Signed-off-by: Honglei Wang Acked-by: Tejun Heo Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmstat.c: fix vmstat_update() preemption BUG

2018-03-28T23:42:05Z

Attempting to hotplug CPUs with CONFIG_VM_EVENT_COUNTERS enabled can cause vmstat_update() to report a BUG due to preemption not being disabled around smp_processor_id(). Discovered on Ubiquiti EdgeRouter Pro with Cavium Octeon II processor. BUG: using smp_processor_id() in preemptible [00000000] code: kworker/1:1/269 caller is vmstat_update+0x50/0xa0 CPU: 0 PID: 269 Comm: kworker/1:1 Not tainted 4.16.0-rc4-Cavium-Octeon-00009-gf83bbd5-dirty #1 Workqueue: mm_percpu_wq vmstat_update Call Trace: show_stack+0x94/0x128 dump_stack+0xa4/0xe0 check_preemption_disabled+0x118/0x120 vmstat_update+0x50/0xa0 process_one_work+0x144/0x348 worker_thread+0x150/0x4b8 kthread+0x110/0x140 ret_from_kernel_thread+0x14/0x1c Link: http://lkml.kernel.org/r/1520881552-25659-1-git-send-email-steven.hill@cavium.com Signed-off-by: Steven J. Hill Reviewed-by: Andrew Morton Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/page_owner: fix recursion bug after changing skip entries

2018-03-28T23:42:05Z

This patch fixes commit 5f48f0bd4e36 ("mm, page_owner: skip unnecessary stack_trace entries"). Because if we skip first two entries then logic of checking count value as 2 for recursion is broken and code will go in one depth recursion. so we need to check only one call of _RET_IP(__set_page_owner) while checking for recursion. Current Backtrace while checking for recursion:- (save_stack) from (__set_page_owner) // (But recursion returns true here) (__set_page_owner) from (get_page_from_freelist) (get_page_from_freelist) from (__alloc_pages_nodemask) (__alloc_pages_nodemask) from (depot_save_stack) (depot_save_stack) from (save_stack) // recursion should return true here (save_stack) from (__set_page_owner) (__set_page_owner) from (get_page_from_freelist) (get_page_from_freelist) from (__alloc_pages_nodemask+) (__alloc_pages_nodemask) from (depot_save_stack) (depot_save_stack) from (save_stack) (save_stack) from (__set_page_owner) (__set_page_owner) from (get_page_from_freelist) Correct Backtrace with fix: (save_stack) from (__set_page_owner) // recursion returned true here (__set_page_owner) from (get_page_from_freelist) (get_page_from_freelist) from (__alloc_pages_nodemask+) (__alloc_pages_nodemask) from (depot_save_stack) (depot_save_stack) from (save_stack) (save_stack) from (__set_page_owner) (__set_page_owner) from (get_page_from_freelist) Link: http://lkml.kernel.org/r/1521607043-34670-1-git-send-email-maninder1.s@samsung.com Fixes: 5f48f0bd4e36 ("mm, page_owner: skip unnecessary stack_trace entries") Signed-off-by: Maninder Singh Signed-off-by: Vaneet Narang Acked-by: Vlastimil Babka Cc: Michal Hocko Cc: Oscar Salvador Cc: Greg Kroah-Hartman Cc: Ayush Mittal Cc: Prakash Gupta Cc: Vinayak Menon Cc: Vasyl Gomonovych Cc: Amit Sahrawat Cc: Cc: Vaneet Narang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, slab: memcg_link the SLAB's kmem_cache

2018-03-28T23:42:05Z

All the root caches are linked into slab_root_caches which was introduced by the commit 510ded33e075 ("slab: implement slab_root_caches list") but it missed to add the SLAB's kmem_cache. While experimenting with opt-in/opt-out kmem accounting, I noticed system crashes due to NULL dereference inside cache_from_memcg_idx() while deferencing kmem_cache.memcg_params.memcg_caches. The upstream clean kernel will not see these crashes but SLAB should be consistent with SLUB which does linked its boot caches (kmem_cache_node and kmem_cache) into slab_root_caches. Link: http://lkml.kernel.org/r/20180319210020.60289-1-shakeelb@google.com Fixes: 510ded33e075c ("slab: implement slab_root_caches list") Signed-off-by: Shakeel Butt Cc: Tejun Heo Cc: Vladimir Davydov Cc: Greg Thelen Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, thp: do not cause memcg oom for thp

2018-03-23T00:07:02Z

Commit 2516035499b9 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations") changed the page allocator to no longer detect thp allocations based on __GFP_NORETRY. It did not, however, modify the mem cgroup try_charge() path to avoid oom kill for either khugepaged collapsing or thp faulting. It is never expected to oom kill a process to allocate a hugepage for thp; reclaim is governed by the thp defrag mode and MADV_HUGEPAGE, but allocations (and charging) should fallback instead of oom killing processes. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803191409420.124411@chino.kir.corp.google.com Fixes: 2516035499b9 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations") Signed-off-by: David Rientjes Cc: "Kirill A. Shutemov" Cc: Michal Hocko Cc: Vlastimil Babka Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmscan: wake up flushers for legacy cgroups too

2018-03-23T00:07:01Z

Commit 726d061fbd36 ("mm: vmscan: kick flushers when we encounter dirty pages on the LRU") added flusher invocation to shrink_inactive_list() when many dirty pages on the LRU are encountered. However, shrink_inactive_list() doesn't wake up flushers for legacy cgroup reclaim, so the next commit bbef938429f5 ("mm: vmscan: remove old flusher wakeup from direct reclaim path") removed the only source of flusher's wake up in legacy mem cgroup reclaim path. This leads to premature OOM if there is too many dirty pages in cgroup: # mkdir /sys/fs/cgroup/memory/test # echo $$ > /sys/fs/cgroup/memory/test/tasks # echo 50M > /sys/fs/cgroup/memory/test/memory.limit_in_bytes # dd if=/dev/zero of=tmp_file bs=1M count=100 Killed dd invoked oom-killer: gfp_mask=0x14000c0(GFP_KERNEL), nodemask=(null), order=0, oom_score_adj=0 Call Trace: dump_stack+0x46/0x65 dump_header+0x6b/0x2ac oom_kill_process+0x21c/0x4a0 out_of_memory+0x2a5/0x4b0 mem_cgroup_out_of_memory+0x3b/0x60 mem_cgroup_oom_synchronize+0x2ed/0x330 pagefault_out_of_memory+0x24/0x54 __do_page_fault+0x521/0x540 page_fault+0x45/0x50 Task in /test killed as a result of limit of /test memory: usage 51200kB, limit 51200kB, failcnt 73 memory+swap: usage 51200kB, limit 9007199254740988kB, failcnt 0 kmem: usage 296kB, limit 9007199254740988kB, failcnt 0 Memory cgroup stats for /test: cache:49632KB rss:1056KB rss_huge:0KB shmem:0KB mapped_file:0KB dirty:49500KB writeback:0KB swap:0KB inactive_anon:0KB active_anon:1168KB inactive_file:24760KB active_file:24960KB unevictable:0KB Memory cgroup out of memory: Kill process 3861 (bash) score 88 or sacrifice child Killed process 3876 (dd) total-vm:8484kB, anon-rss:1052kB, file-rss:1720kB, shmem-rss:0kB oom_reaper: reaped process 3876 (dd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB Wake up flushers in legacy cgroup reclaim too. Link: http://lkml.kernel.org/r/20180315164553.17856-1-aryabinin@virtuozzo.com Fixes: bbef938429f5 ("mm: vmscan: remove old flusher wakeup from direct reclaim path") Signed-off-by: Andrey Ryabinin Tested-by: Shakeel Butt Acked-by: Michal Hocko Cc: Mel Gorman Cc: Tejun Heo Cc: Johannes Weiner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Revert "mm: page_alloc: skip over regions of invalid pfns where possible"

2018-03-23T00:07:01Z

This reverts commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible"). The commit is meant to be a boot init speed up skipping the loop in memmap_init_zone() for invalid pfns. But given some specific memory mapping on x86_64 (or more generally theoretically anywhere but on arm with CONFIG_HAVE_ARCH_PFN_VALID) the implementation also skips valid pfns which is plain wrong and causes 'kernel BUG at mm/page_alloc.c:1389!' crash> log | grep -e BUG -e RIP -e Call.Trace -e move_freepages_block -e rmqueue -e freelist -A1 kernel BUG at mm/page_alloc.c:1389! invalid opcode: 0000 [#1] SMP -- RIP: 0010: move_freepages+0x15e/0x160 -- Call Trace: move_freepages_block+0x73/0x80 __rmqueue+0x263/0x460 get_page_from_freelist+0x7e1/0x9e0 __alloc_pages_nodemask+0x176/0x420 -- crash> page_init_bug -v | grep RAM 1000 - 9bfff System RAM (620.00 KiB) 100000 - 430bffff System RAM ( 1.05 GiB = 1071.75 MiB = 1097472.00 KiB) 4b0c8000 - 4bf9cfff System RAM ( 14.83 MiB = 15188.00 KiB) 4bfac000 - 646b1fff System RAM (391.02 MiB = 400408.00 KiB) 7b788000 - 7b7fffff System RAM (480.00 KiB) 100000000 - 67fffffff System RAM ( 22.00 GiB) crash> page_init_bug | head -6 7b788000 - 7b7fffff System RAM (480.00 KiB) 1fffff00000000 0 1 DMA32 4096 1048575 505736 505344 505855 0 0 0 DMA 1 4095 1fffff00000400 0 1 DMA32 4096 1048575 BUG, zones differ! crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b787000 7b788000 PAGE PHYSICAL MAPPING INDEX CNT FLAGS ffffea0001e00000 78000000 0 0 0 0 ffffea0001ed7fc0 7b5ff000 0 0 0 0 ffffea0001ed8000 7b600000 0 0 0 0 <<<< ffffea0001ede1c0 7b787000 0 0 0 0 ffffea0001ede200 7b788000 0 0 1 1fffff00000000 Link: http://lkml.kernel.org/r/20180316143855.29838-1-neelx@redhat.com Fixes: b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") Signed-off-by: Daniel Vacek Acked-by: Ard Biesheuvel Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Vlastimil Babka Cc: Mel Gorman Cc: Pavel Tatashin Cc: Paul Burton Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/shmem: do not wait for lock_page() in shmem_unused_huge_shrink()

2018-03-23T00:07:01Z

shmem_unused_huge_shrink() gets called from reclaim path. Waiting for page lock may lead to deadlock there. There was a bug report that may be attributed to this: http://lkml.kernel.org/r/alpine.LRH.2.11.1801242349220.30642@mail.ewheeler.net Replace lock_page() with trylock_page() and skip the page if we failed to lock it. We will get to the page on the next scan. We can test for the PageTransHuge() outside the page lock as we only need protection against splitting the page under us. Holding pin oni the page is enough for this. Link: http://lkml.kernel.org/r/20180316210830.43738-1-kirill.shutemov@linux.intel.com Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure") Signed-off-by: Kirill A. Shutemov Reported-by: Eric Wheeler Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Tetsuo Handa Cc: Hugh Dickins Cc: [4.8+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/thp: do not wait for lock_page() in deferred_split_scan()

2018-03-23T00:07:01Z

deferred_split_scan() gets called from reclaim path. Waiting for page lock may lead to deadlock there. Replace lock_page() with trylock_page() and skip the page if we failed to lock it. We will get to the page on the next scan. Link: http://lkml.kernel.org/r/20180315150747.31945-1-kirill.shutemov@linux.intel.com Fixes: 9a982250f773 ("thp: introduce deferred_split_huge_page()") Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds