- 25 Mar, 2016 40 commits
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Alexander Potapenko authored
Add KASAN hooks to SLAB allocator. This patch is based on the "mm: kasan: unified support for SLUB and SLAB allocators" patch originally prepared by Dmitry Chernenkov. Signed-off-by:
Alexander Potapenko <glider@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> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Alexander Potapenko authored
This patchset implements SLAB support for KASAN Unlike SLUB, SLAB doesn't store allocation/deallocation stacks for heap objects, therefore we reimplement this feature in mm/kasan/stackdepot.c. The intention is to ultimately switch SLUB to use this implementation as well, which will save a lot of memory (right now SLUB bloats each object by 256 bytes to store the allocation/deallocation stacks). Also neither SLUB nor SLAB delay the reuse of freed memory chunks, which is necessary for better detection of use-after-free errors. We introduce memory quarantine (mm/kasan/quarantine.c), which allows delayed reuse of deallocated memory. This patch (of 7): Rename kmalloc_large_oob_right() to kmalloc_pagealloc_oob_right(), as the test only checks the page allocator functionality. Also reimplement kmalloc_large_oob_right() so that the test allocates a large enough chunk of memory that still does not trigger the page allocator fallback. Signed-off-by:
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Tetsuo Handa authored
A leftover from commit c32b3cbe ("oom, PM: make OOM detection in the freezer path raceless"). Signed-off-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
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Vlastimil Babka authored
Hanjun Guo has reported that a CMA stress test causes broken accounting of CMA and free pages: > Before the test, I got: > -bash-4.3# cat /proc/meminfo | grep Cma > CmaTotal: 204800 kB > CmaFree: 195044 kB > > > After running the test: > -bash-4.3# cat /proc/meminfo | grep Cma > CmaTotal: 204800 kB > CmaFree: 6602584 kB > > So the freed CMA memory is more than total.. > > Also the the MemFree is more than mem total: > > -bash-4.3# cat /proc/meminfo > MemTotal: 16342016 kB > MemFree: 22367268 kB > MemAvailable: 22370528 kB Laura Abbott has confirmed the issue and suspected the freepage accounting rewrite around 3.18/4.0 by Joonsoo Kim. Joonsoo had a theory that this is caused by unexpected merging between MIGRATE_ISOLATE and MIGRATE_CMA pageblocks: > CMA isolates MAX_ORDER aligned blocks, but, during the process, > partialy isolated block exists. If MAX_ORDER is 11 and > pageblock_order is 9, two pageblocks make up MAX_ORDER > aligned block and I can think following scenario because pageblock > (un)isolation would be done one by one. > > (each character means one pageblock. 'C', 'I' means MIGRATE_CMA, > MIGRATE_ISOLATE, respectively. > > CC -> IC -> II (Isolation) > II -> CI -> CC (Un-isolation) > > If some pages are freed at this intermediate state such as IC or CI, > that page could be merged to the other page that is resident on > different type of pageblock and it will cause wrong freepage count. This was supposed to be prevented by CMA operating on MAX_ORDER blocks, but since it doesn't hold the zone->lock between pageblocks, a race window does exist. It's also likely that unexpected merging can occur between MIGRATE_ISOLATE and non-CMA pageblocks. This should be prevented in __free_one_page() since commit 3c605096 ("mm/page_alloc: restrict max order of merging on isolated pageblock"). However, we only check the migratetype of the pageblock where buddy merging has been initiated, not the migratetype of the buddy pageblock (or group of pageblocks) which can be MIGRATE_ISOLATE. Joonsoo has suggested checking for buddy migratetype as part of page_is_buddy(), but that would add extra checks in allocator hotpath and bloat-o-meter has shown significant code bloat (the function is inline). This patch reduces the bloat at some expense of more complicated code. The buddy-merging while-loop in __free_one_page() is initially bounded to pageblock_border and without any migratetype checks. The checks are placed outside, bumping the max_order if merging is allowed, and returning to the while-loop with a statement which can't be possibly considered harmful. This fixes the accounting bug and also removes the arguably weird state in the original commit 3c605096 where buddies could be left unmerged. Fixes: 3c605096 ("mm/page_alloc: restrict max order of merging on isolated pageblock") Link: https://lkml.org/lkml/2016/3/2/280Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Reported-by:
Hanjun Guo <guohanjun@huawei.com> Tested-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Debugged-by:
Laura Abbott <labbott@redhat.com> Debugged-by:
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Arnd Bergmann authored
The r592 driver relies on behavior of the DMA mapping API that is normally observed but not guaranteed by the API. Instead it uses a runtime check to fail transfers if the API ever behaves When CONFIG_NEED_SG_DMA_LENGTH is not set, one of the checks turns into a comparison of a variable with itself, which gcc-6.0 now warns about: drivers/memstick/host/r592.c: In function 'r592_transfer_fifo_dma': drivers/memstick/host/r592.c:302:31: error: self-comparison always evaluates to false [-Werror=tautological-compare] (sg_dma_len(&dev->req->sg) < dev->req->sg.length)) { ^ The check itself is not a problem, so this patch just rephrases the condition in a way that gcc does not consider an indication of a mistake. We already know that dev->req->sg.length was initially R592_LFIFO_SIZE, so we can compare it to that constant again. Signed-off-by:Arnd Bergmann <arnd@arndb.de> Cc: Maxim Levitsky <maximlevitsky@gmail.com> Cc: Quentin Lambert <lambert.quentin@gmail.com> Signed-off-by:
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Xue jiufei authored
Now function ocfs2_replay_truncate_records() first modifies tl_used, then calls ocfs2_extend_trans() to extend transactions for gd and alloc inode used for freeing clusters. jbd2_journal_restart() may be called and it may happen that tl_used in truncate log is decreased but the clusters are not freed, which means these clusters are lost. So we should avoid extending transactions in these two operations. Signed-off-by:
joyce.xue <xuejiufei@huawei.com> Reviewed-by:
Mark Fasheh <mfasheh@suse.de> Acked-by:
Joseph Qi <joseph.qi@huawei.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by:
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Xue jiufei authored
ocfs2: extend transaction for ocfs2_remove_rightmost_path() and ocfs2_update_edge_lengths() before to avoid inconsistency between inode and et I found that jbd2_journal_restart() is called in some places without keeping things consistently before. However, jbd2_journal_restart() may commit the handle's transaction and restart another one. If the first transaction is committed successfully while another not, it may cause filesystem inconsistency or read only. This is an effort to fix this kind of problems. This patch (of 3): The following functions will be called while truncating an extent: ocfs2_remove_btree_range -> ocfs2_start_trans -> ocfs2_remove_extent -> ocfs2_truncate_rec -> ocfs2_extend_rotate_transaction -> jbd2_journal_restart if jbd2_journal_extend fail -> ocfs2_rotate_tree_left -> ocfs2_remove_rightmost_path -> ocfs2_extend_rotate_transaction -> ocfs2_unlink_subtree -> ocfs2_update_edge_lengths -> ocfs2_extend_trans -> jbd2_journal_restart if jbd2_journal_extend fail -> ocfs2_et_update_clusters -> ocfs2_commit_trans jbd2_journal_restart() may be called and it may happened that the buffers dirtied in ocfs2_truncate_rec() are committed while buffers dirtied in ocfs2_et_update_clusters() are not, the total clusters on extent tree and i_clusters in ocfs2_dinode is inconsistency. So the clusters got from ocfs2_dinode is incorrect, and it also cause read-only problem when call ocfs2_commit_truncate() with the error message: "Inode %llu has empty extent block at %llu". We should extend enough credits for function ocfs2_remove_rightmost_path and ocfs2_update_edge_lengths to avoid this inconsistency. Signed-off-by: -
xuejiufei authored
We have found a bug when two nodes doing umount one after another. 1) Node 1 migrate a lockres that has 3 locks in grant queue such as N2(PR)<->N3(NL)<->N4(PR) to N2. After migration, lvb of the lock N3(NL) and N4(PR) are empty on node 2 because migration target do not copy lvb to these two lock. 2) Node 3 want to convert to PR, it can be granted in __dlmconvert_master(), and the order of these locks is unchanged. The lvb of the lock N3(PR) on node 2 is copyed from lockres in function dlm_update_lvb() while the lvb of lock N4(PR) is still empty. 3) Node 2 want to leave domain, it will migrate this lockres to node 3. Then node 2 will trigger the BUG in dlm_prepare_lvb_for_migration() when adding the lock N4(PR) to mres with the following message because the lvb of mres is already copied from lock N3(PR), but the lvb of lock N4(PR) is empty. "Mismatched lvb in lock cookie=%u:%llu, name=%.*s, node=%u" [akpm@linux-foundation.org: tweak comment] Signed-off-by:
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jiangyiwen authored
In update_backups() there exists a problem of crossing the boundary as follows: we assume that lun will be resized to 1TB(cluster_size is 32kb), it will include 0~33554431 cluster, in update_backups func, it will backup super block in location of 1TB which is the 33554432th cluster, so the phenomenon of crossing the boundary happens. Signed-off-by:
Yiwen Jiang <jiangyiwen@huawei.com> Reviewed-by:
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jiangyiwen authored
This patch fixes a deadlock, as follows: Node 1 Node 2 Node 3 1)volume a and b are only mount vol a only mount vol b mounted 2) start to mount b start to mount a 3) check hb of Node 3 check hb of Node 2 in vol a, qs_holds++ in vol b, qs_holds++ 4) -------------------- all nodes' network down -------------------- 5) progress of mount b the same situation as failed, and then call Node 2 ocfs2_dismount_volume. but the process is hung, since there is a work in ocfs2_wq cannot beo completed. This work is about vol a, because ocfs2_wq is global wq. BTW, this work which is scheduled in ocfs2_wq is ocfs2_orphan_scan_work, and the context in this work needs to take inode lock of orphan_dir, because lockres owner are Node 1 and all nodes' nework has been down at the same time, so it can't get the inode lock. 6) Why can't this node be fenced when network disconnected? Because the process of mount is hung what caused qs_holds is not equal 0. Because all works in the ocfs2_wq are relative to the super block. The solution is to change the ocfs2_wq from global to local. In other words, move it into struct ocfs2_super. Signed-off-by: -
Joseph Qi authored
When master handles convert request, it queues ast first and then returns status. This may happen that the ast is sent before the request status because the above two messages are sent by two threads. And right after the ast is sent, if master down, it may trigger BUG in dlm_move_lockres_to_recovery_list in the requested node because ast handler moves it to grant list without clear lock->convert_pending. So remove BUG_ON statement and check if the ast is processed in dlmconvert_remote. Signed-off-by:
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Joseph Qi authored
There is a race window between dlmconvert_remote and dlm_move_lockres_to_recovery_list, which will cause a lock with OCFS2_LOCK_BUSY in grant list, thus system hangs. dlmconvert_remote { spin_lock(&res->spinlock); list_move_tail(&lock->list, &res->converting); lock->convert_pending = 1; spin_unlock(&res->spinlock); status = dlm_send_remote_convert_request(); >>>>>> race window, master has queued ast and return DLM_NORMAL, and then down before sending ast. this node detects master down and calls dlm_move_lockres_to_recovery_list, which will revert the lock to grant list. Then OCFS2_LOCK_BUSY won't be cleared as new master won't send ast any more because it thinks already be authorized. spin_lock(&res->spinlock); lock->convert_pending = 0; if (status != DLM_NORMAL) dlm_revert_pending_convert(res, lock); spin_unlock(&res->spinlock); } In this case, check if res->state has DLM_LOCK_RES_RECOVERING bit set (res is still in recovering) or res master changed (new master has finished recovery), reset the status to DLM_RECOVERING, then it will retry convert. Signed-off-by:Junxiao Bi <junxiao.bi@oracle.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Cc: Tariq Saeed <tariq.x.saeed@oracle.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Ryan Ding authored
The code should call ocfs2_free_alloc_context() to free meta_ac & data_ac before calling ocfs2_run_deallocs(). Because ocfs2_run_deallocs() will acquire the system inode's i_mutex hold by meta_ac. So try to release the lock before ocfs2_run_deallocs(). Fixes: af1310367f41 ("ocfs2: fix sparse file & data ordering issue in direct io.") Signed-off-by:Ryan Ding <ryan.ding@oracle.com> Acked-by:
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Ryan Ding authored
When doing append direct write in an already allocated cluster, and fast path in ocfs2_dio_get_block() is triggered, function ocfs2_dio_end_io_write() will be skipped as there is no context allocated. As a result, the disk file size will not be changed as it should be. The solution is to skip fast path when we are about to change file size. Fixes: af1310367f41 ("ocfs2: fix sparse file & data ordering issue in direct io.") Signed-off-by: -
Ryan Ding authored
Take ip_alloc_sem to prevent concurrent access to extent tree, which may cause the extent tree in an unstable state. Signed-off-by:
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Ryan Ding authored
In the current implementation of unaligned aio+dio, lock order behave as follow: in user process context: -> call io_submit() -> get i_mutex <== window1 -> get ip_unaligned_aio -> submit direct io to block device -> release i_mutex -> io_submit() return in dio work queue context(the work queue is created in __blockdev_direct_IO): -> release ip_unaligned_aio <== window2 -> get i_mutex -> clear unwritten flag & change i_size -> release i_mutex There is a limitation to the thread number of dio work queue. 256 at default. If all 256 thread are in the above 'window2' stage, and there is a user process in the 'window1' stage, the system will became deadlock. Since the user process hold i_mutex to wait ip_unaligned_aio lock, while there is a direct bio hold ip_unaligned_aio mutex who is waiting for a dio work queue thread to be schedule. But all the dio work queue thread is waiting for i_mutex lock in 'window2'. This case only happened in a test which send a large number(more than 256) of aio at one io_submit() call. My design is to remove ip_unaligned_aio lock. Change it to a sync io instead. Just like ip_unaligned_aio lock, serialize the unaligned aio dio. [akpm@linux-foundation.org: remove OCFS2_IOCB_UNALIGNED_IO, per Junxiao Bi] Signed-off-by: -
Ryan Ding authored
Clean up ocfs2_file_write_iter & ocfs2_prepare_inode_for_write: * remove append dio check: it will be checked in ocfs2_direct_IO() * remove file hole check: file hole is supported for now * remove inline data check: it will be checked in ocfs2_direct_IO() * remove the full_coherence check when append dio: we will get the inode_lock in ocfs2_dio_get_block, there is no need to fall back to buffer io to ensure the coherence semantics. Now the drop dio procedure is gone. :) [akpm@linux-foundation.org: remove unused label] Signed-off-by:
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Ryan Ding authored
There are mainly three issues in the direct io code path after commit 24c40b32 ("ocfs2: implement ocfs2_direct_IO_write"): * Does not support sparse file. * Does not support data ordering. eg: when write to a file hole, it will alloc extent first. If system crashed before io finished, data will corrupt. * Potential risk when doing aio+dio. The -EIOCBQUEUED return value is likely to be ignored by ocfs2_direct_IO_write(). To resolve above problems, re-design direct io code with following ideas: * Use buffer io to fill in holes. And this will make better performance also. * Clear unwritten after direct write finished. So we can make sure meta data changes after data write to disk. (Unwritten extent is invisible to user, from user's view, meta data is not changed when allocate an unwritten extent.) * Clear ocfs2_direct_IO_write(). Do all ending work in end_io. This patch has passed fs,dio,ltp-aiodio.part1,ltp-aiodio.part2,ltp-aiodio.part4 test cases of ltp. For performance improvement, see following test result: ocfs2 cluster size 1MB, ocfs2 volume is mounted on /mnt/. The original way: + rm /mnt/test.img -f + dd if=/dev/zero of=/mnt/test.img bs=4K count=1048576 oflag=direct 1048576+0 records in 1048576+0 records out 4294967296 bytes (4.3 GB) copied, 1707.83 s, 2.5 MB/s + rm /mnt/test.img -f + dd if=/dev/zero of=/mnt/test.img bs=256K count=16384 oflag=direct 16384+0 records in 16384+0 records out 4294967296 bytes (4.3 GB) copied, 582.705 s, 7.4 MB/s After this patch: + rm /mnt/test.img -f + dd if=/dev/zero of=/mnt/test.img bs=4K count=1048576 oflag=direct 1048576+0 records in 1048576+0 records out 4294967296 bytes (4.3 GB) copied, 64.6412 s, 66.4 MB/s + rm /mnt/test.img -f + dd if=/dev/zero of=/mnt/test.img bs=256K count=16384 oflag=direct 16384+0 records in 16384+0 records out 4294967296 bytes (4.3 GB) copied, 34.7611 s, 124 MB/s Signed-off-by:
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Ryan Ding authored
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. There is still one issue in the direct write procedure. phase 1: alloc extent with UNWRITTEN flag phase 2: submit direct data to disk, add zero page to page cache phase 3: clear UNWRITTEN flag when data has been written to disk When there are 2 direct write A(0~3KB),B(4~7KB) writing to the same cluster 0~7KB (cluster size 8KB). Write request A arrive phase 2 first, it will zero the region (4~7KB). Before request A enter to phase 3, request B arrive phase 2, it will zero region (0~3KB). This is just like request B steps request A. To resolve this issue, we should let request B knows this cluster is already under zero, to prevent it from steps the previous write request. This patch will add function ocfs2_unwritten_check() to do this job. It will record all clusters that are under direct write(it will be recorded in the 'ip_unwritten_list' member of inode info), and prevent the later direct write writing to the same cluster to do the zero work again. Signed-off-by:
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Ryan Ding authored
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. Direct io needs to get the physical address from write_begin, to map the user page. This patch is to change the arg 'phys' of ocfs2_write_cluster to a pointer, so it can be retrieved to write_begin. And we can retrieve it to the direct io procedure. Signed-off-by:
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Ryan Ding authored
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. Append direct io do not change i_size in get block phase. It only move to orphan when starting write. After data is written to disk, it will delete itself from orphan and update i_size. So skip i_size change section in write_begin for direct io. And when there is no extents alloc, no meta data changes needed for direct io (since write_begin start trans for 2 reason: alloc extents & change i_size. Now none of them needed). So we can skip start trans procedure. Signed-off-by:
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Ryan Ding authored
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. Direct io data will not appear in buffer. The w_target_page member will not be filled by direct io. So avoid to use it when it's NULL. Unlinke buffer io and mmap, direct io will call write_begin with more than 1 page a time. So the target_index is not sufficient to describe the actual data. change it to a range start at target_index, end in end_index. Signed-off-by:
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Ryan Ding authored
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. There is a problem in ocfs2's direct io implement: if system crashed after extents allocated, and before data return, we will get a extent with dirty data on disk. This problem violate the journal=order semantics, which means meta changes take effect after data written to disk. To resolve this issue, direct write can use the UNWRITTEN flag to describe a extent during direct data writeback. The direct write procedure should act in the following order: phase 1: alloc extent with UNWRITTEN flag phase 2: submit direct data to disk, add zero page to page cache phase 3: clear UNWRITTEN flag when data has been written to disk This patch is to change the 'c_unwritten' member of ocfs2_write_cluster_desc to 'c_clear_unwritten'. Means whether to clear the unwritten flag. It do not care if a extent is allocated or not. And use 'c_new' to specify a newly allocated extent. So the direct io procedure can use c_clear_unwritten to control the UNWRITTEN bit on extent. Signed-off-by:
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Ryan Ding authored
Patchset: fix ocfs2 direct io code patch to support sparse file and data ordering semantics The idea is to use buffer io(more precisely use the interface ocfs2_write_begin_nolock & ocfs2_write_end_nolock) to do the zero work beyond block size. And clear UNWRITTEN flag until direct io data has been written to disk, which can prevent data corruption when system crashed during direct write. And we will also archive a better performance: eg. dd direct write new file with block size 4KB: before this patchset: 2.5 MB/s after this patchset: 66.4 MB/s This patch (of 8): To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock. Remove unused args filp & flags. Add new arg type. The type is one of buffer/direct/mmap. Indicate 3 way to perform write. buffer/mmap type has implemented. direct type will be implemented later. Signed-off-by:
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Junxiao Bi authored
This is a regression issue and caused the following kernel panic when do ocfs2 multiple test. BUG: unable to handle kernel paging request at 00000002000800c0 IP: [<ffffffff81192978>] kmem_cache_alloc+0x78/0x160 PGD 7bbe5067 PUD 0 Oops: 0000 [#1] SMP Modules linked in: ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi xen_kbdfront xen_netfront xen_fbfront xen_blkfront CPU: 2 PID: 4044 Comm: mpirun Not tainted 4.5.0-rc5-next-20160225 #1 Hardware name: Xen HVM domU, BIOS 4.3.1OVM 05/14/2014 task: ffff88007a521a80 ti: ffff88007aed0000 task.ti: ffff88007aed0000 RIP: 0010:[<ffffffff81192978>] [<ffffffff81192978>] kmem_cache_alloc+0x78/0x160 RSP: 0018:ffff88007aed3a48 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000001991 RDX: 0000000000001990 RSI: 00000000024000c0 RDI: 000000000001b330 RBP: ffff88007aed3a98 R08: ffff88007d29b330 R09: 00000002000800c0 R10: 0000000c51376d87 R11: ffff8800792cac38 R12: ffff88007cc30f00 R13: 00000000024000c0 R14: ffffffff811b053f R15: ffff88007aed3ce7 FS: 0000000000000000(0000) GS:ffff88007d280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000002000800c0 CR3: 000000007aeb2000 CR4: 00000000000406e0 Call Trace: __d_alloc+0x2f/0x1a0 d_alloc+0x17/0x80 lookup_dcache+0x8a/0xc0 path_openat+0x3c3/0x1210 do_filp_open+0x80/0xe0 do_sys_open+0x110/0x200 SyS_open+0x19/0x20 do_syscall_64+0x72/0x230 entry_SYSCALL64_slow_path+0x25/0x25 Code: 05 e6 77 e7 7e 4d 8b 08 49 8b 40 10 4d 85 c9 0f 84 dd 00 00 00 48 85 c0 0f 84 d4 00 00 00 49 63 44 24 20 49 8b 3c 24 48 8d 4a 01 <49> 8b 1c 01 4c 89 c8 65 48 0f c7 0f 0f 94 c0 3c 01 75 b6 49 63 RIP kmem_cache_alloc+0x78/0x160 CR2: 00000002000800c0 ---[ end trace 823969e602e4aaac ]--- Fixes: a4a1dfa4("ocfs2/cluster: fix memory leak in o2hb_region_release") Signed-off-by: -
Andrew Morton authored
INPUT_COMPAT_TEST became much simpler after commit f4056b52 ("input: redefine INPUT_COMPAT_TEST as in_compat_syscall()") so we can cleanly eliminate it altogether. Acked-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Signed-off-by:
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Tetsuo Handa authored
"oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task" tried to protect oom_reaper_list using MMF_OOM_KILLED flag. But we can do it by simply checking tsk->oom_reaper_list != NULL. Signed-off-by:
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Michal Hocko authored
After "oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space" oom_reaper will call exit_oom_victim on the target task after it is done. This might however race with the PM freezer: CPU0 CPU1 CPU2 freeze_processes try_to_freeze_tasks # Allocation request out_of_memory oom_killer_disable wake_oom_reaper(P1) __oom_reap_task exit_oom_victim(P1) wait_event(oom_victims==0) [...] do_exit(P1) perform IO/interfere with the freezer which breaks the oom_killer_disable semantic. We no longer have a guarantee that the oom victim won't interfere with the freezer because it might be anywhere on the way to do_exit while the freezer thinks the task has already terminated. It might trigger IO or touch devices which are frozen already. In order to close this race, make the oom_reaper thread freezable. This will work because a) already running oom_reaper will block freezer to enter the quiescent state b) wake_oom_reaper will not wake up the reaper after it has been frozen c) the only way to call exit_oom_victim after try_to_freeze_tasks is from the oom victim's context when we know the further interference shouldn't be possible Signed-off-by: -
Vladimir Davydov authored
Entries are only added/removed from oom_reaper_list at head so we can use a single linked list and hence save a word in task_struct. Signed-off-by:
Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by:
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Michal Hocko authored
Tetsuo has reported that oom_kill_allocating_task=1 will cause oom_reaper_list corruption because oom_kill_process doesn't follow standard OOM exclusion (aka ignores TIF_MEMDIE) and allows to enqueue the same task multiple times - e.g. by sacrificing the same child multiple times. This patch fixes the issue by introducing a new MMF_OOM_KILLED mm flag which is set in oom_kill_process atomically and oom reaper is disabled if the flag was already set. Signed-off-by:
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Michal Hocko authored
wake_oom_reaper has allowed only 1 oom victim to be queued. The main reason for that was the simplicity as other solutions would require some way of queuing. The current approach is racy and that was deemed sufficient as the oom_reaper is considered a best effort approach to help with oom handling when the OOM victim cannot terminate in a reasonable time. The race could lead to missing an oom victim which can get stuck out_of_memory wake_oom_reaper cmpxchg // OK oom_reaper oom_reap_task __oom_reap_task oom_victim terminates atomic_inc_not_zero // fail out_of_memory wake_oom_reaper cmpxchg // fails task_to_reap = NULL This race requires 2 OOM invocations in a short time period which is not very likely but certainly not impossible. E.g. the original victim might have not released a lot of memory for some reason. The situation would improve considerably if wake_oom_reaper used a more robust queuing. This is what this patch implements. This means adding oom_reaper_list list_head into task_struct (eat a hole before embeded thread_struct for that purpose) and a oom_reaper_lock spinlock for queuing synchronization. wake_oom_reaper will then add the task on the queue and oom_reaper will dequeue it. Signed-off-by: -
Michal Hocko authored
Inform about the successful/failed oom_reaper attempts and dump all the held locks to tell us more who is blocking the progress. [akpm@linux-foundation.org: fix CONFIG_MMU=n build] Signed-off-by:
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Michal Hocko authored
When oom_reaper manages to unmap all the eligible vmas there shouldn't be much of the freable memory held by the oom victim left anymore so it makes sense to clear the TIF_MEMDIE flag for the victim and allow the OOM killer to select another task. The lack of TIF_MEMDIE also means that the victim cannot access memory reserves anymore but that shouldn't be a problem because it would get the access again if it needs to allocate and hits the OOM killer again due to the fatal_signal_pending resp. PF_EXITING check. We can safely hide the task from the OOM killer because it is clearly not a good candidate anymore as everyhing reclaimable has been torn down already. This patch will allow to cap the time an OOM victim can keep TIF_MEMDIE and thus hold off further global OOM killer actions granted the oom reaper is able to take mmap_sem for the associated mm struct. This is not guaranteed now but further steps should make sure that mmap_sem for write should be blocked killable which will help to reduce such a lock contention. This is not done by this patch. Note that exit_oom_victim might be called on a remote task from __oom_reap_task now so we have to check and clear the flag atomically otherwise we might race and underflow oom_victims or wake up waiters too early. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Suggested-by:
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Michal Hocko authored
This patch (of 5): This is based on the idea from Mel Gorman discussed during LSFMM 2015 and independently brought up by Oleg Nesterov. The OOM killer currently allows to kill only a single task in a good hope that the task will terminate in a reasonable time and frees up its memory. Such a task (oom victim) will get an access to memory reserves via mark_oom_victim to allow a forward progress should there be a need for additional memory during exit path. It has been shown (e.g. by Tetsuo Handa) that it is not that hard to construct workloads which break the core assumption mentioned above and the OOM victim might take unbounded amount of time to exit because it might be blocked in the uninterruptible state waiting for an event (e.g. lock) which is blocked by another task looping in the page allocator. This patch reduces the probability of such a lockup by introducing a specialized kernel thread (oom_reaper) which tries to reclaim additional memory by preemptively reaping the anonymous or swapped out memory owned by the oom victim under an assumption that such a memory won't be needed when its owner is killed and kicked from the userspace anyway. There is one notable exception to this, though, if the OOM victim was in the process of coredumping the result would be incomplete. This is considered a reasonable constrain because the overall system health is more important than debugability of a particular application. A kernel thread has been chosen because we need a reliable way of invocation so workqueue context is not appropriate because all the workers might be busy (e.g. allocating memory). Kswapd which sounds like another good fit is not appropriate as well because it might get blocked on locks during reclaim as well. oom_reaper has to take mmap_sem on the target task for reading so the solution is not 100% because the semaphore might be held or blocked for write but the probability is reduced considerably wrt. basically any lock blocking forward progress as described above. In order to prevent from blocking on the lock without any forward progress we are using only a trylock and retry 10 times with a short sleep in between. Users of mmap_sem which need it for write should be carefully reviewed to use _killable waiting as much as possible and reduce allocations requests done with the lock held to absolute minimum to reduce the risk even further. The API between oom killer and oom reaper is quite trivial. wake_oom_reaper updates mm_to_reap with cmpxchg to guarantee only NULL->mm transition and oom_reaper clear this atomically once it is done with the work. This means that only a single mm_struct can be reaped at the time. As the operation is potentially disruptive we are trying to limit it to the ncessary minimum and the reaper blocks any updates while it operates on an mm. mm_struct is pinned by mm_count to allow parallel exit_mmap and a race is detected by atomic_inc_not_zero(mm_users). Signed-off-by:
Oleg Nesterov <oleg@redhat.com> Suggested-by:
Mel Gorman <mgorman@suse.de> Acked-by:
David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Argangeli <andrea@kernel.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by:
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Andrew Morton authored
This will be needed in the patch "mm, oom: introduce oom reaper". Acked-by:
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Linus Torvalds authored
This reverts commit e7223f18. It causes problems when a ppdev tries to register before the parport driver has been registered with the device model. That will trigger the BUG_ON(!drv->bus->p); at drivers/base/driver.c:153. The call chain is kernel_init -> kernel_init_freeable -> do_one_initcall -> ppdev_init -> __parport_register_driver -> driver_register *BOOM* Reported-by:
kernel test robot <fengguang.wu@intel.com> Reported-by:
Ross Zwisler <zwisler@gmail.com> Reported-by:
Petr Mladek <pmladek@suse.com> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394Linus Torvalds authored
Pull firewire leftover from Stefan Richter: "Occurrences of timeval were supposed to be eliminated last round, now remove a last forgotten one" * tag 'firewire-update2' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394: firewire: nosy: Replace timeval with timespec64
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git://people.freedesktop.org/~airlied/linuxLinus Torvalds authored
Pull drm fixes from Dave Airlie: "Just a couple of dma-buf related fixes and some amdgpu fixes, along with a regression fix for radeon off but default feature, but makes my 30" monitor happy again" * 'drm-next' of git://people.freedesktop.org/~airlied/linux: drm/radeon/mst: cleanup code indentation drm/radeon/mst: fix regression in lane/link handling. drm/amdgpu: add invalidate_page callback for userptrs drm/amdgpu: Revert "remove the userptr rmn->lock" drm/amdgpu: clean up path handling for powerplay drm/amd/powerplay: fix memory leak of tdp_table dma-buf/fence: fix fence_is_later v2 dma-buf: Update docs for SYNC ioctl drm: remove excess description dma-buf, drm, ion: Propagate error code from dma_buf_start_cpu_access() drm/atmel-hlcdc: use helper to get crtc state drm/atomic: use helper to get crtc state
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git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-genericLinus Torvalds authored
Pull asm-generic updates from Arnd Bergmann: "There are only three patches this time, most other changes to files in include/asm-generic tend to go through the tree of whoever depends on the change. Two patches are cleanups for stuff that is no longer needed, the main change is to adapt the generic version of BUG_ON() for CONFIG_BUG=n to make it behave consistently with BUG(). This avoids undefined behavior along with a number of warnings about that undefined behavior in randconfig builds when we keep going on after hitting a BUG_ON()" * tag 'asm-generic-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: asm-generic: remove old nonatomic-io wrapper files asm-generic: default BUG_ON(x) to if(x)BUG() asm-generic: page.h: Remove useless get_user_page and free_user_page
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git://people.freedesktop.org/~agd5f/linuxDave Airlie authored
some amd fixes * 'drm-next-4.6' of git://people.freedesktop.org/~agd5f/linux: drm/radeon/mst: cleanup code indentation drm/radeon/mst: fix regression in lane/link handling. drm/amdgpu: add invalidate_page callback for userptrs drm/amdgpu: Revert "remove the userptr rmn->lock" drm/amdgpu: clean up path handling for powerplay drm/amd/powerplay: fix memory leak of tdp_table
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