syzbot

reiserfs: enabling write barrier flush mode
REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.104-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/7740 is trying to acquire lock:
ffff000116385090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff0000c13ec460 (sb_writers#16){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2447 [inline]
ffff0000c13ec460 (sb_writers#16){.+.+}-{0:0}, at: iterate_dir+0x400/0x4e4 fs/readdir.c:70

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#16){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1742 [inline]
       sb_start_write+0xf0/0x3ac include/linux/fs.h:1812
       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:596
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&sbi->lock){+.+.}-{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:3787 [inline]
       __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
       __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_dirty_inode+0xe4/0x204 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x2b0/0x10f4 fs/fs-writeback.c:2439
       generic_update_time fs/inode.c:1775 [inline]
       inode_update_time fs/inode.c:1788 [inline]
       touch_atime+0x4d0/0xa4c fs/inode.c:1860
       file_accessed include/linux/fs.h:2447 [inline]
       iterate_dir+0x400/0x4e4 fs/readdir.c:70
       __do_sys_getdents64 fs/readdir.c:369 [inline]
       __se_sys_getdents64 fs/readdir.c:354 [inline]
       __arm64_sys_getdents64+0x1c4/0x4c4 fs/readdir.c:354
       __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:596
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#16);
                               lock(&sbi->lock);
                               lock(sb_writers#16);
  lock(&sbi->lock);

 *** DEADLOCK ***

3 locks held by syz-executor.2/7740:
 #0: ffff00012930e0f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xdc/0x108 fs/file.c:1073
 #1: ffff0000df4b02e0 (&type->i_mutex_dir_key#13){++++}-{3:3}, at: iterate_dir+0x108/0x4e4 fs/readdir.c:55
 #2: ffff0000c13ec460 (sb_writers#16){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2447 [inline]
 #2: ffff0000c13ec460 (sb_writers#16){.+.+}-{0:0}, at: iterate_dir+0x400/0x4e4 fs/readdir.c:70

stack backtrace:
CPU: 0 PID: 7740 Comm: syz-executor.2 Not tainted 5.15.104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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:3787 [inline]
 __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
 __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_dirty_inode+0xe4/0x204 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x2b0/0x10f4 fs/fs-writeback.c:2439
 generic_update_time fs/inode.c:1775 [inline]
 inode_update_time fs/inode.c:1788 [inline]
 touch_atime+0x4d0/0xa4c fs/inode.c:1860
 file_accessed include/linux/fs.h:2447 [inline]
 iterate_dir+0x400/0x4e4 fs/readdir.c:70
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64 fs/readdir.c:354 [inline]
 __arm64_sys_getdents64+0x1c4/0x4c4 fs/readdir.c:354
 __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:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584