syzbot


possible deadlock in ocfs2_nfs_sync_lock

Status: upstream: reported syz repro on 2024/08/31 09:46
Subsystems: ocfs2
[Documentation on labels]
Reported-by: syzbot+fcb79916dcfe2a4ed10a@syzkaller.appspotmail.com
First crash: 38d, last: 16d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [ocfs2?] possible deadlock in ocfs2_nfs_sync_lock 1 (3) 2024/08/31 12:50
Last patch testing requests (2)
Created Duration User Patch Repo Result
2024/10/02 08:18 21m retest repro upstream OK log
2024/08/31 12:28 21m hdanton@sina.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a18093afa393 OK log

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-04557-g2f27fce67173 #0 Not tainted
------------------------------------------------------
kswapd0/78 is trying to acquire lock:
ffff8880359f0bd0 (&osb->nfs_sync_rwlock){.+.+}-{3:3}, at: ocfs2_nfs_sync_lock+0x109/0x260 fs/ocfs2/dlmglue.c:2876

but task is already holding lock:
ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6821 [inline]
ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3720 mm/vmscan.c:7203

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __fs_reclaim_acquire mm/page_alloc.c:3825 [inline]
       fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3839
       might_alloc include/linux/sched/mm.h:334 [inline]
       slab_pre_alloc_hook mm/slub.c:3940 [inline]
       slab_alloc_node mm/slub.c:4018 [inline]
       __kmalloc_cache_noprof+0x3d/0x2c0 mm/slub.c:4185
       kmalloc_noprof include/linux/slab.h:690 [inline]
       kzalloc_noprof include/linux/slab.h:816 [inline]
       ocfs2_reserve_new_metadata_blocks+0x117/0x9c0 fs/ocfs2/suballoc.c:966
       ocfs2_mknod+0x143a/0x2b40 fs/ocfs2/namei.c:345
       ocfs2_mkdir+0x1ab/0x480 fs/ocfs2/namei.c:655
       vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
       do_mkdirat+0x264/0x3a0 fs/namei.c:4280
       __do_sys_mkdir fs/namei.c:4300 [inline]
       __se_sys_mkdir fs/namei.c:4298 [inline]
       __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4298
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       down_write+0x99/0x220 kernel/locking/rwsem.c:1579
       inode_lock include/linux/fs.h:815 [inline]
       ocfs2_remove_inode fs/ocfs2/inode.c:655 [inline]
       ocfs2_wipe_inode fs/ocfs2/inode.c:818 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1079 [inline]
       ocfs2_evict_inode+0x209f/0x4680 fs/ocfs2/inode.c:1216
       evict+0x4e8/0x9b0 fs/inode.c:731
       ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
       __dentry_kill+0x20d/0x630 fs/dcache.c:615
       dput+0x19f/0x2b0 fs/dcache.c:857
       ovl_check_rename_whiteout fs/overlayfs/super.c:592 [inline]
       ovl_make_workdir fs/overlayfs/super.c:691 [inline]
       ovl_get_workdir+0xc6c/0x1920 fs/overlayfs/super.c:814
       ovl_fill_super+0x12a8/0x3560 fs/overlayfs/super.c:1382
       vfs_get_super fs/super.c:1280 [inline]
       get_tree_nodev+0xb7/0x140 fs/super.c:1299
       vfs_get_tree+0x90/0x2b0 fs/super.c:1800
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4055 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       down_write+0x99/0x220 kernel/locking/rwsem.c:1579
       inode_lock include/linux/fs.h:815 [inline]
       ocfs2_wipe_inode fs/ocfs2/inode.c:776 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1079 [inline]
       ocfs2_evict_inode+0x1b17/0x4680 fs/ocfs2/inode.c:1216
       evict+0x4e8/0x9b0 fs/inode.c:731
       ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
       __dentry_kill+0x20d/0x630 fs/dcache.c:615
       dput+0x19f/0x2b0 fs/dcache.c:857
       ovl_check_rename_whiteout fs/overlayfs/super.c:592 [inline]
       ovl_make_workdir fs/overlayfs/super.c:691 [inline]
       ovl_get_workdir+0xc6c/0x1920 fs/overlayfs/super.c:814
       ovl_fill_super+0x12a8/0x3560 fs/overlayfs/super.c:1382
       vfs_get_super fs/super.c:1280 [inline]
       get_tree_nodev+0xb7/0x140 fs/super.c:1299
       vfs_get_tree+0x90/0x2b0 fs/super.c:1800
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4055 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&osb->nfs_sync_rwlock){.+.+}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
       ocfs2_nfs_sync_lock+0x109/0x260 fs/ocfs2/dlmglue.c:2876
       ocfs2_delete_inode fs/ocfs2/inode.c:1030 [inline]
       ocfs2_evict_inode+0x3e5/0x4680 fs/ocfs2/inode.c:1216
       evict+0x4e8/0x9b0 fs/inode.c:731
       ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
       __dentry_kill+0x20d/0x630 fs/dcache.c:615
       shrink_kill+0xa9/0x2c0 fs/dcache.c:1060
       shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087
       prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168
       super_cache_scan+0x34f/0x4b0 fs/super.c:221
       do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
       shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
       shrink_one+0x43b/0x850 mm/vmscan.c:4795
       shrink_many mm/vmscan.c:4856 [inline]
       lru_gen_shrink_node mm/vmscan.c:4934 [inline]
       shrink_node+0x3799/0x3de0 mm/vmscan.c:5914
       kswapd_shrink_node mm/vmscan.c:6742 [inline]
       balance_pgdat mm/vmscan.c:6934 [inline]
       kswapd+0x1cbc/0x3720 mm/vmscan.c:7203
       kthread+0x2f0/0x390 kernel/kthread.c:389
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Chain exists of:
  &osb->nfs_sync_rwlock --> &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2 --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2);
                               lock(fs_reclaim);
  rlock(&osb->nfs_sync_rwlock);

 *** DEADLOCK ***

2 locks held by kswapd0/78:
 #0: ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6821 [inline]
 #0: ffffffff8ea30460 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3720 mm/vmscan.c:7203
 #1: ffff88804c7c40e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
 #1: ffff88804c7c40e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Not tainted 6.11.0-syzkaller-04557-g2f27fce67173 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
 ocfs2_nfs_sync_lock+0x109/0x260 fs/ocfs2/dlmglue.c:2876
 ocfs2_delete_inode fs/ocfs2/inode.c:1030 [inline]
 ocfs2_evict_inode+0x3e5/0x4680 fs/ocfs2/inode.c:1216
 evict+0x4e8/0x9b0 fs/inode.c:731
 ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
 __dentry_kill+0x20d/0x630 fs/dcache.c:615
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1060
 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087
 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168
 super_cache_scan+0x34f/0x4b0 fs/super.c:221
 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
 shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
 shrink_one+0x43b/0x850 mm/vmscan.c:4795
 shrink_many mm/vmscan.c:4856 [inline]
 lru_gen_shrink_node mm/vmscan.c:4934 [inline]
 shrink_node+0x3799/0x3de0 mm/vmscan.c:5914
 kswapd_shrink_node mm/vmscan.c:6742 [inline]
 balance_pgdat mm/vmscan.c:6934 [inline]
 kswapd+0x1cbc/0x3720 mm/vmscan.c:7203
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/18 08:11 upstream 2f27fce67173 c673ca06 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
2024/09/11 07:38 upstream 8d8d276ba2fb 8ab55d0e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
2024/09/11 05:00 upstream 8d8d276ba2fb 8ab55d0e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
2024/09/09 10:29 upstream da3ea35007d0 9750182a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
2024/09/05 16:03 upstream c763c4339688 36ae3a26 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
2024/08/29 01:56 upstream a18093afa393 ef3de9e8 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
2024/08/27 09:38 upstream 3e9bff3bbe13 9aee4e0b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in ocfs2_nfs_sync_lock
* Struck through repros no longer work on HEAD.