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possible deadlock in vfs_fileattr_set

Status: upstream: reported C repro on 2024/03/27 09:48
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+4c1ea7bac08a9dd127b3@syzkaller.appspotmail.com
First crash: 299d, last: 15d
Fix commit to backport (bisect log) :
tree: upstream
commit fb6f20ecb121cef4d7946f834a6ee867c4e21b4a
Author: Jan Kara <jack@suse.cz>
Date: Thu Oct 17 10:28:23 2024 +0000

  reiserfs: The last commit

  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2024/12/28 linux-6.1.y (ToT) 563edd786f0a C [report] possible deadlock in vfs_fileattr_set
2024/03/27 upstream (ToT) 962490525cff C [report] possible deadlock in vfs_fileattr_set
2024/12/28 upstream (ToT) fd0584d220fe C Didn't crash
▶ ▼ Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in vfs_fileattr_set 1 649d 649d 0/3 auto-obsoleted due to no activity on 2023/08/10 15:05
upstream possible deadlock in vfs_fileattr_set reiserfs C done 10 518d 799d 0/28 auto-obsoleted due to no activity on 2023/11/29 02:28
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2025/01/03 08:51 7h18m fix candidate upstream OK (1) job log
2024/05/30 23:12 12m bisect fix linux-6.1.y error job log
2024/04/28 00:08 1h52m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
6.1.123-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor852/4293 is trying to acquire lock:
ffff0000e1bb82e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff0000e1bb82e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: vfs_fileattr_set+0x110/0xad4 fs/ioctl.c:681

but task is already holding lock:
ffff0000d9dc4460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#8){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1891 [inline]
       sb_start_write+0x7c/0x308 include/linux/fs.h:1966
       mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437
       reiserfs_ioctl+0x184/0x454 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x130/0x3c4 fs/reiserfs/namei.c:364
       __lookup_slow+0x250/0x374 fs/namei.c:1690
       lookup_one_len+0x178/0x28c fs/namei.c:2740
       reiserfs_lookup_privroot+0x8c/0x204 fs/reiserfs/xattr.c:973
       reiserfs_fill_super+0x1bc0/0x2028 fs/reiserfs/super.c:2174
       mount_bdev+0x274/0x370 fs/super.c:1443
       get_super_block+0x44/0x58 fs/reiserfs/super.c:2601
       legacy_get_tree+0xd4/0x16c fs/fs_context.c:632
       vfs_get_tree+0x90/0x274 fs/super.c:1573
       do_new_mount+0x278/0x8fc fs/namespace.c:3056
       path_mount+0x590/0xe5c fs/namespace.c:3386
       do_mount fs/namespace.c:3399 [inline]
       __do_sys_mount fs/namespace.c:3607 [inline]
       __se_sys_mount fs/namespace.c:3584 [inline]
       __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3584
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
       down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       vfs_fileattr_set+0x110/0xad4 fs/ioctl.c:681
       do_vfs_ioctl+0x14cc/0x26f8
       __do_sys_ioctl fs/ioctl.c:868 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#6 --> &sbi->lock --> sb_writers#8

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#8);
                               lock(&sbi->lock);
                               lock(sb_writers#8);
  lock(&type->i_mutex_dir_key#6);

 *** DEADLOCK ***

1 lock held by syz-executor852/4293:
 #0: ffff0000d9dc4460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437

stack backtrace:
CPU: 1 PID: 4293 Comm: syz-executor852 Not tainted 6.1.123-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
 down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 vfs_fileattr_set+0x110/0xad4 fs/ioctl.c:681
 do_vfs_ioctl+0x14cc/0x26f8
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/05 05:57 linux-6.1.y 7dc732d24ff7 f3558dbf .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_fileattr_set
2024/03/27 13:40 linux-6.1.y e5cd595e23c1 454571b6 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_fileattr_set
2024/03/27 09:47 linux-6.1.y e5cd595e23c1 454571b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in vfs_fileattr_set
* Struck through repros no longer work on HEAD.