syzbot

syz.0.17[5956]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set
loop0: detected capacity change from 0 to 32768
syz.0.17: attempt to access beyond end of device
loop14: rw=0, sector=8, nr_sectors = 8 limit=0
lbmIODone: I/O error in JFS log
*** Log Format Error ! ***
lmLogInit: exit(-22)
lmLogOpen: exit(-22)
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/5956 is trying to acquire lock:
ffff88802ce980e0 (&type->s_umount_key#56){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
ffff88802ce980e0 (&type->s_umount_key#56){++++}-{3:3}, at: super_lock+0x167/0x360 fs/super.c:117

but task is already holding lock:
ffff888148c8c608 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:379 [inline]
ffff888148c8c608 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x815/0x2460 block/ioctl.c:511

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&bdev->bd_holder_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
       bd_finish_claiming+0x22f/0x3f0 block/bdev.c:585
       blkdev_get_by_dev+0x45c/0x600 block/bdev.c:818
       bdev_open_by_dev+0x77/0x100 block/bdev.c:859
       setup_bdev_super+0x59/0x660 fs/super.c:1496
       mount_bdev+0x1dd/0x2d0 fs/super.c:1640
       legacy_get_tree+0xea/0x180 fs/fs_context.c:662
       vfs_get_tree+0x8c/0x280 fs/super.c:1764
       do_new_mount+0x24b/0xa40 fs/namespace.c:3386
       init_mount+0xd2/0x120 fs/init.c:25
       do_mount_root+0x97/0x230 init/do_mounts.c:166
       mount_root_generic+0x195/0x3c0 init/do_mounts.c:205
       prepare_namespace+0xc2/0x100 init/do_mounts.c:489
       kernel_init_freeable+0x413/0x570 init/main.c:1578
       kernel_init+0x1d/0x1c0 init/main.c:1455
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

-> #2 (bdev_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
       bd_prepare_to_claim+0x1ba/0x480 block/bdev.c:527
       blkdev_get_by_dev+0xb1/0x600 block/bdev.c:793
       bdev_open_by_dev+0x77/0x100 block/bdev.c:859
       lmLogOpen+0x7a1/0xfb0 fs/jfs/jfs_logmgr.c:1103
       jfs_mount_rw+0xea/0x670 fs/jfs/jfs_mount.c:257
       jfs_remount+0x396/0x5b0 fs/jfs/super.c:454
       reconfigure_super+0x21e/0x880 fs/super.c:1151
       do_remount fs/namespace.c:2927 [inline]
       path_mount+0xd19/0xfe0 fs/namespace.c:3705
       do_mount fs/namespace.c:3726 [inline]
       __do_sys_mount fs/namespace.c:3935 [inline]
       __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (jfs_log_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
       lmLogOpen+0xca/0xfb0 fs/jfs/jfs_logmgr.c:1071
       jfs_mount_rw+0xea/0x670 fs/jfs/jfs_mount.c:257
       jfs_remount+0x396/0x5b0 fs/jfs/super.c:454
       reconfigure_super+0x21e/0x880 fs/super.c:1151
       do_remount fs/namespace.c:2927 [inline]
       path_mount+0xd19/0xfe0 fs/namespace.c:3705
       do_mount fs/namespace.c:3726 [inline]
       __do_sys_mount fs/namespace.c:3935 [inline]
       __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&type->s_umount_key#56){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
       lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
       __super_lock fs/super.c:58 [inline]
       super_lock+0x167/0x360 fs/super.c:117
       super_lock_shared fs/super.c:146 [inline]
       super_lock_shared_active fs/super.c:1442 [inline]
       fs_bdev_sync+0xa4/0x170 fs/super.c:1477
       blkdev_flushbuf block/ioctl.c:381 [inline]
       blkdev_common_ioctl+0x881/0x2460 block/ioctl.c:511
       blkdev_ioctl+0x4eb/0x6f0 block/ioctl.c:633
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:871 [inline]
       __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  &type->s_umount_key#56 --> bdev_lock --> &bdev->bd_holder_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&bdev->bd_holder_lock);
                               lock(bdev_lock);
                               lock(&bdev->bd_holder_lock);
  rlock(&type->s_umount_key#56);

 *** DEADLOCK ***

1 lock held by syz.0.17/5956:
 #0: ffff888148c8c608 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_flushbuf block/ioctl.c:379 [inline]
 #0: ffff888148c8c608 (&bdev->bd_holder_lock){+.+.}-{3:3}, at: blkdev_common_ioctl+0x815/0x2460 block/ioctl.c:511

stack backtrace:
CPU: 0 PID: 5956 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
 __super_lock fs/super.c:58 [inline]
 super_lock+0x167/0x360 fs/super.c:117
 super_lock_shared fs/super.c:146 [inline]
 super_lock_shared_active fs/super.c:1442 [inline]
 fs_bdev_sync+0xa4/0x170 fs/super.c:1477
 blkdev_flushbuf block/ioctl.c:381 [inline]
 blkdev_common_ioctl+0x881/0x2460 block/ioctl.c:511
 blkdev_ioctl+0x4eb/0x6f0 block/ioctl.c:633
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f15ec58efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff92e10c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f15ec7e5fa0 RCX: 00007f15ec58efc9
RDX: 0000000000000000 RSI: 0000000000001261 RDI: 0000000000000004
RBP: 00007f15ec611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f15ec7e5fa0 R14: 00007f15ec7e5fa0 R15: 0000000000000003
 </TASK>