syzbot


possible deadlock in chown_common

Status: upstream: reported on 2023/09/04 16:29
Reported-by: syzbot+097db46a03bf76e49ae4@syzkaller.appspotmail.com
First crash: 180d, last: 44d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 possible deadlock in chown_common C 1 375d 514d 0/1 upstream: reported C repro on 2022/10/05 17:28
linux-6.1 possible deadlock in chown_common 1 226d 226d 0/3 auto-obsoleted due to no activity on 2023/10/28 14:17
upstream possible deadlock in chown_common reiserfs C error done 22 40d 509d 26/26 fixed on 2024/01/30 15:47

Sample crash report:
REISERFS (device loop5): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.147-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/7212 is trying to acquire lock:
ffff00011c491020 (&type->i_mutex_dir_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff00011c491020 (&type->i_mutex_dir_key#12){+.+.}-{3:3}, at: chown_common+0x3f8/0x74c fs/open.c:674

but task is already holding lock:
ffff00011e4b4460 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#18){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1785 [inline]
       sb_start_write+0xf0/0x3ac include/linux/fs.h:1855
       mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421
       reiserfs_ioctl+0x188/0x4b8 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x130/0x3c4 fs/reiserfs/namei.c:364
       __lookup_slow+0x250/0x388 fs/namei.c:1663
       lookup_one_len+0x178/0x28c fs/namei.c:2718
       reiserfs_lookup_privroot+0x8c/0x204 fs/reiserfs/xattr.c:980
       reiserfs_fill_super+0x1aec/0x1e8c fs/reiserfs/super.c:2178
       mount_bdev+0x274/0x370 fs/super.c:1387
       get_super_block+0x44/0x58 fs/reiserfs/super.c:2608
       legacy_get_tree+0xd4/0x16c fs/fs_context.c:611
       vfs_get_tree+0x90/0x274 fs/super.c:1517
       do_new_mount+0x25c/0x8c4 fs/namespace.c:2994
       path_mount+0x594/0x101c fs/namespace.c:3324
       do_mount fs/namespace.c:3337 [inline]
       __do_sys_mount fs/namespace.c:3545 [inline]
       __se_sys_mount fs/namespace.c:3522 [inline]
       __arm64_sys_mount+0x510/0x5e0 fs/namespace.c:3522
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&type->i_mutex_dir_key#12){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       down_write+0x110/0x260 kernel/locking/rwsem.c:1541
       inode_lock include/linux/fs.h:787 [inline]
       chown_common+0x3f8/0x74c fs/open.c:674
       vfs_fchown fs/open.c:748 [inline]
       ksys_fchown+0xe0/0x158 fs/open.c:759
       __do_sys_fchown fs/open.c:767 [inline]
       __se_sys_fchown fs/open.c:765 [inline]
       __arm64_sys_fchown+0x7c/0x94 fs/open.c:765
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#12 --> &sbi->lock --> sb_writers#18

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#18);
                               lock(&sbi->lock);
                               lock(sb_writers#18);
  lock(&type->i_mutex_dir_key#12);

 *** DEADLOCK ***

1 lock held by syz-executor.5/7212:
 #0: ffff00011e4b4460 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421

stack backtrace:
CPU: 0 PID: 7212 Comm: syz-executor.5 Not tainted 5.15.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __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:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 down_write+0x110/0x260 kernel/locking/rwsem.c:1541
 inode_lock include/linux/fs.h:787 [inline]
 chown_common+0x3f8/0x74c fs/open.c:674
 vfs_fchown fs/open.c:748 [inline]
 ksys_fchown+0xe0/0x158 fs/open.c:759
 __do_sys_fchown fs/open.c:767 [inline]
 __se_sys_fchown fs/open.c:765 [inline]
 __arm64_sys_fchown+0x7c/0x94 fs/open.c:765
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/01/18 17:07 linux-5.15.y ddcaf4999061 239abf84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in chown_common
2023/10/24 20:25 linux-5.15.y 00c03985402e 17e6d526 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in chown_common
2023/10/20 17:53 linux-5.15.y 00c03985402e 361b23dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in chown_common
2023/09/04 16:29 linux-5.15.y 8f790700c974 db3306a6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in chown_common
* Struck through repros no longer work on HEAD.