syzbot


possible deadlock in start_this_handle (3)

Status: fixed on 2023/02/24 13:50
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+2d2aeadc6ce1e1f11d45@syzkaller.appspotmail.com
Fix commit: 68aaee147e59 mm: memcontrol: fix potential oom_lock recursion deadlock
First crash: 639d, last: 449d
Discussions (3)
Title Replies (including bot) Last reply
Re: + mm-memcontrol-fix-potential-oom_lock-recursion-deadlock.patch added to mm-unstable branch 4 (4) 2022/07/26 18:50
[PATCH] mm: memcontrol: fix potential oom_lock recursion deadlock 7 (7) 2022/07/22 11:12
[syzbot] possible deadlock in start_this_handle (3) 4 (5) 2022/07/15 01:53
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in start_this_handle (2) ext4 8 1123d 1156d 0/26 auto-closed as invalid on 2021/07/13 16:11
upstream possible deadlock in start_this_handle (4) fscrypt ext4 23 29d 408d 0/26 upstream: reported on 2023/03/01 00:02
upstream possible deadlock in start_this_handle ext4 8 2005d 2044d 0/26 auto-closed as invalid on 2019/04/13 16:27

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc4-syzkaller-00041-gc1649ec55708 #0 Not tainted
------------------------------------------------------
syz-executor.2/11953 is trying to acquire lock:
ffff88804423c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfb4/0x14a0 fs/jbd2/transaction.c:461

but task is already holding lock:
ffffffff8c8ceda0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4747 [inline]
ffffffff8c8ceda0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4772 [inline]
ffffffff8c8ceda0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath.constprop.0+0x808/0x23d0 mm/page_alloc.c:5178

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4674 [inline]
       fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:4688
       might_alloc include/linux/sched/mm.h:271 [inline]
       slab_pre_alloc_hook mm/slab.h:720 [inline]
       slab_alloc_node mm/slab.c:3245 [inline]
       __kmem_cache_alloc_node+0x3b/0x510 mm/slab.c:3544
       __do_kmalloc_node mm/slab_common.c:967 [inline]
       __kmalloc_node+0x4d/0xd0 mm/slab_common.c:975
       kmalloc_node include/linux/slab.h:610 [inline]
       kvmalloc_node+0x76/0x1a0 mm/util.c:581
       kvmalloc include/linux/slab.h:737 [inline]
       ext4_xattr_inode_cache_find fs/ext4/xattr.c:1484 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1527 [inline]
       ext4_xattr_set_entry+0x1d92/0x3a00 fs/ext4/xattr.c:1669
       ext4_xattr_block_set+0xcd3/0x3000 fs/ext4/xattr.c:1975
       ext4_xattr_set_handle+0xd8a/0x1510 fs/ext4/xattr.c:2390
       ext4_xattr_set+0x144/0x360 fs/ext4/xattr.c:2492
       __vfs_setxattr+0x173/0x1e0 fs/xattr.c:202
       __vfs_setxattr_noperm+0x129/0x5f0 fs/xattr.c:236
       __vfs_setxattr_locked+0x1d3/0x260 fs/xattr.c:297
       vfs_setxattr+0x143/0x340 fs/xattr.c:323
       do_setxattr+0x151/0x190 fs/xattr.c:608
       setxattr+0x146/0x160 fs/xattr.c:631
       path_setxattr+0x197/0x1c0 fs/xattr.c:650
       __do_sys_setxattr fs/xattr.c:666 [inline]
       __se_sys_setxattr fs/xattr.c:662 [inline]
       __x64_sys_setxattr+0xc4/0x160 fs/xattr.c:662
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&ei->xattr_sem){++++}-{3:3}:
       down_write+0x94/0x220 kernel/locking/rwsem.c:1562
       ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
       ext4_xattr_set_handle+0x160/0x1510 fs/ext4/xattr.c:2305
       ext4_initxattrs+0xb9/0x120 fs/ext4/xattr_security.c:44
       security_inode_init_security+0x1c8/0x370 security/security.c:1147
       __ext4_new_inode+0x3b05/0x57d0 fs/ext4/ialloc.c:1324
       ext4_create+0x2da/0x4e0 fs/ext4/namei.c:2809
       lookup_open.isra.0+0xee7/0x1270 fs/namei.c:3413
       open_last_lookups fs/namei.c:3481 [inline]
       path_openat+0x975/0x2a50 fs/namei.c:3711
       do_filp_open+0x1ba/0x410 fs/namei.c:3741
       do_sys_openat2+0x16d/0x4c0 fs/open.c:1310
       do_sys_open fs/open.c:1326 [inline]
       __do_sys_openat fs/open.c:1342 [inline]
       __se_sys_openat fs/open.c:1337 [inline]
       __x64_sys_openat+0x143/0x1f0 fs/open.c:1337
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (jbd2_handle){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain kernel/locking/lockdep.c:3831 [inline]
       __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
       lock_acquire kernel/locking/lockdep.c:5668 [inline]
       lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
       start_this_handle+0xfe7/0x14a0 fs/jbd2/transaction.c:463
       jbd2__journal_start+0x39d/0x9b0 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x6e9/0x860 fs/ext4/ext4_jbd2.c:111
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_dirty_inode+0xa5/0x130 fs/ext4/inode.c:6107
       __mark_inode_dirty+0x247/0x11e0 fs/fs-writeback.c:2419
       mark_inode_dirty_sync include/linux/fs.h:2470 [inline]
       iput.part.0+0x57/0x880 fs/inode.c:1770
       iput+0x5c/0x80 fs/inode.c:1763
       dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
       __dentry_kill+0x3c0/0x640 fs/dcache.c:607
       shrink_dentry_list+0x240/0x800 fs/dcache.c:1201
       prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282
       super_cache_scan+0x33a/0x590 fs/super.c:104
       do_shrink_slab+0x464/0xce0 mm/vmscan.c:843
       shrink_slab+0x175/0x660 mm/vmscan.c:1003
       shrink_node_memcgs mm/vmscan.c:6140 [inline]
       shrink_node+0x95d/0x1f40 mm/vmscan.c:6169
       shrink_zones mm/vmscan.c:6407 [inline]
       do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:6469
       try_to_free_pages+0x2e5/0x960 mm/vmscan.c:6704
       __perform_reclaim mm/page_alloc.c:4750 [inline]
       __alloc_pages_direct_reclaim mm/page_alloc.c:4772 [inline]
       __alloc_pages_slowpath.constprop.0+0x8b6/0x23d0 mm/page_alloc.c:5178
       __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5562
       __folio_alloc+0x16/0x40 mm/page_alloc.c:5581
       vma_alloc_folio+0x155/0x870 mm/mempolicy.c:2247
       shmem_alloc_folio+0xfe/0x1d0 mm/shmem.c:1569
       shmem_alloc_and_acct_folio+0x15e/0x5d0 mm/shmem.c:1593
       shmem_get_folio_gfp+0xb2e/0x1a30 mm/shmem.c:1920
       shmem_get_folio mm/shmem.c:2051 [inline]
       shmem_write_begin+0x14a/0x380 mm/shmem.c:2543
       generic_perform_write+0x256/0x570 mm/filemap.c:3772
       __generic_file_write_iter+0x2ae/0x500 mm/filemap.c:3900
       generic_file_write_iter+0xe3/0x350 mm/filemap.c:3932
       call_write_iter include/linux/fs.h:2189 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x9ed/0xdd0 fs/read_write.c:584
       ksys_write+0x12b/0x250 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  jbd2_handle --> &ei->xattr_sem --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&ei->xattr_sem);
                               lock(fs_reclaim);
  lock(jbd2_handle);

 *** DEADLOCK ***

5 locks held by syz-executor.2/11953:
 #0: ffff8880400c6460 (sb_writers#6){.+.+}-{0:0}, at: ksys_write+0x12b/0x250 fs/read_write.c:637
 #1: ffff88802a0a0288 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
 #1: ffff88802a0a0288 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: generic_file_write_iter+0x92/0x350 mm/filemap.c:3929
 #2: ffffffff8c8ceda0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4747 [inline]
 #2: ffffffff8c8ceda0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4772 [inline]
 #2: ffffffff8c8ceda0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath.constprop.0+0x808/0x23d0 mm/page_alloc.c:5178
 #3: ffffffff8c88c990 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0xc7/0x660 mm/vmscan.c:993
 #4: ffff8880444820e0 (&type->s_umount_key#50){++++}-{3:3}, at: trylock_super fs/super.c:415 [inline]
 #4: ffff8880444820e0 (&type->s_umount_key#50){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79

stack backtrace:
CPU: 0 PID: 11953 Comm: syz-executor.2 Not tainted 6.2.0-rc4-syzkaller-00041-gc1649ec55708 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain kernel/locking/lockdep.c:3831 [inline]
 __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
 lock_acquire kernel/locking/lockdep.c:5668 [inline]
 lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
 start_this_handle+0xfe7/0x14a0 fs/jbd2/transaction.c:463
 jbd2__journal_start+0x39d/0x9b0 fs/jbd2/transaction.c:520
 __ext4_journal_start_sb+0x6e9/0x860 fs/ext4/ext4_jbd2.c:111
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0xa5/0x130 fs/ext4/inode.c:6107
 __mark_inode_dirty+0x247/0x11e0 fs/fs-writeback.c:2419
 mark_inode_dirty_sync include/linux/fs.h:2470 [inline]
 iput.part.0+0x57/0x880 fs/inode.c:1770
 iput+0x5c/0x80 fs/inode.c:1763
 dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
 __dentry_kill+0x3c0/0x640 fs/dcache.c:607
 shrink_dentry_list+0x240/0x800 fs/dcache.c:1201
 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282
 super_cache_scan+0x33a/0x590 fs/super.c:104
 do_shrink_slab+0x464/0xce0 mm/vmscan.c:843
 shrink_slab+0x175/0x660 mm/vmscan.c:1003
 shrink_node_memcgs mm/vmscan.c:6140 [inline]
 shrink_node+0x95d/0x1f40 mm/vmscan.c:6169
 shrink_zones mm/vmscan.c:6407 [inline]
 do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:6469
 try_to_free_pages+0x2e5/0x960 mm/vmscan.c:6704
 __perform_reclaim mm/page_alloc.c:4750 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4772 [inline]
 __alloc_pages_slowpath.constprop.0+0x8b6/0x23d0 mm/page_alloc.c:5178
 __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5562
 __folio_alloc+0x16/0x40 mm/page_alloc.c:5581
 vma_alloc_folio+0x155/0x870 mm/mempolicy.c:2247
 shmem_alloc_folio+0xfe/0x1d0 mm/shmem.c:1569
 shmem_alloc_and_acct_folio+0x15e/0x5d0 mm/shmem.c:1593
 shmem_get_folio_gfp+0xb2e/0x1a30 mm/shmem.c:1920
 shmem_get_folio mm/shmem.c:2051 [inline]
 shmem_write_begin+0x14a/0x380 mm/shmem.c:2543
 generic_perform_write+0x256/0x570 mm/filemap.c:3772
 __generic_file_write_iter+0x2ae/0x500 mm/filemap.c:3900
 generic_file_write_iter+0xe3/0x350 mm/filemap.c:3932
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x9ed/0xdd0 fs/read_write.c:584
 ksys_write+0x12b/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f60d563de4f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 99 fd ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 cc fd ff ff 48
RSP: 002b:00007f60d6359f10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f60d563de4f
RDX: 0000000008000000 RSI: 00007f60cbdff000 RDI: 0000000000000003
RBP: 00007f60cbdff000 R08: 0000000000000000 R09: 0000000000022099
R10: 0000000008000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f60d6359fdc R14: 00007f60d6359fe0 R15: 0000000020022182
 </TASK>

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/01/18 13:13 upstream c1649ec55708 4620c2d9 .config console log report info ci-qemu-upstream possible deadlock in start_this_handle
2022/09/19 13:01 upstream 521a547ced64 dd9a85ff .config console log report info ci-qemu-upstream possible deadlock in start_this_handle
2022/08/01 16:03 upstream 3d7cb6b04c3f fef302b1 .config console log report info ci-qemu-upstream possible deadlock in start_this_handle
2022/09/25 00:36 upstream 1a61b828566f 0042f2b4 .config console log report info ci-qemu-upstream-386 possible deadlock in start_this_handle
2022/09/24 00:25 upstream 1707c39ae309 0042f2b4 .config console log report info ci-qemu-upstream-386 possible deadlock in start_this_handle
2022/09/16 16:58 upstream 6879c2d3b960 dd9a85ff .config console log report info ci-qemu-upstream-386 possible deadlock in start_this_handle
2022/07/30 21:48 upstream 620725263f42 fef302b1 .config console log report info ci-qemu-upstream-386 possible deadlock in start_this_handle
2022/07/12 18:06 upstream 5a29232d870d d91dd8ea .config console log report info ci-qemu-upstream-386 possible deadlock in start_this_handle
* Struck through repros no longer work on HEAD.