syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor/5770 is trying to acquire lock:
ffff88805a074ae8 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xaf/0x670 fs/gfs2/quota.c:689

but task is already holding lock:
ffff888078f30ca0 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1543 [inline]
ffff888078f30ca0 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x1d80/0x2ec0 fs/gfs2/bmap.c:1867

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ip->i_rw_mutex){++++}-{3:3}:
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
       __gfs2_iomap_get+0x15f/0x1400 fs/gfs2/bmap.c:862
       gfs2_iomap_get+0xef/0x170 fs/gfs2/bmap.c:1427
       bh_get+0x251/0x760 fs/gfs2/quota.c:401
       qdsb_get+0x210/0x330 fs/gfs2/quota.c:535
       gfs2_quota_hold+0x198/0x5e0 fs/gfs2/quota.c:615
       gfs2_quota_lock+0xba/0x7b0 fs/gfs2/quota.c:1070
       gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
       gfs2_iomap_begin_write fs/gfs2/bmap.c:1033 [inline]
       gfs2_iomap_begin+0x770/0x13b0 fs/gfs2/bmap.c:1132
       iomap_iter+0x6b1/0xec0 fs/iomap/iter.c:91
       iomap_file_buffered_write+0xbc0/0xd80 fs/iomap/buffered-io.c:999
       gfs2_file_buffered_write+0x4bd/0x820 fs/gfs2/file.c:1060
       gfs2_file_write_iter+0x48d/0xe90 fs/gfs2/file.c:1158
       call_write_iter include/linux/fs.h:2018 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x46c/0x990 fs/read_write.c:584
       ksys_write+0x150/0x260 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&sdp->sd_quota_mutex){+.+.}-{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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
       lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
       do_qc+0xaf/0x670 fs/gfs2/quota.c:689
       gfs2_quota_change+0x2b9/0x800 fs/gfs2/quota.c:1289
       punch_hole+0x2902/0x2ec0 fs/gfs2/bmap.c:1968
       evict_unlinked_inode fs/gfs2/super.c:1420 [inline]
       gfs2_evict_inode+0xd6a/0x1350 fs/gfs2/super.c:1523
       evict+0x4ca/0x8d0 fs/inode.c:705
       do_unlinkat+0x38c/0x590 fs/namei.c:4406
       __do_sys_unlink fs/namei.c:4447 [inline]
       __se_sys_unlink fs/namei.c:4445 [inline]
       __x64_sys_unlink+0x49/0x50 fs/namei.c:4445
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ip->i_rw_mutex);
                               lock(&sdp->sd_quota_mutex);
                               lock(&ip->i_rw_mutex);
  lock(&sdp->sd_quota_mutex);

 *** DEADLOCK ***

4 locks held by syz-executor/5770:
 #0: ffff8880310fe418 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
 #1: ffff8880310fe608 (sb_internal#3){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118
 #2: ffff88805a075060 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x517/0x890 fs/gfs2/trans.c:87
 #3: ffff888078f30ca0 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1543 [inline]
 #3: ffff888078f30ca0 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x1d80/0x2ec0 fs/gfs2/bmap.c:1867

stack backtrace:
CPU: 1 PID: 5770 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 check_noncircular+0x2fc/0x400 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+0x2df1/0x7d40 kernel/locking/lockdep.c:5137
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x136/0xcc0 kernel/locking/mutex.c:747
 do_qc+0xaf/0x670 fs/gfs2/quota.c:689
 gfs2_quota_change+0x2b9/0x800 fs/gfs2/quota.c:1289
 punch_hole+0x2902/0x2ec0 fs/gfs2/bmap.c:1968
 evict_unlinked_inode fs/gfs2/super.c:1420 [inline]
 gfs2_evict_inode+0xd6a/0x1350 fs/gfs2/super.c:1523
 evict+0x4ca/0x8d0 fs/inode.c:705
 do_unlinkat+0x38c/0x590 fs/namei.c:4406
 __do_sys_unlink fs/namei.c:4447 [inline]
 __se_sys_unlink fs/namei.c:4445 [inline]
 __x64_sys_unlink+0x49/0x50 fs/namei.c:4445
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc62339b907
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe7dcfa2f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc62339b907
RDX: 00007ffe7dcfa320 RSI: 00007ffe7dcfa3b0 RDI: 00007ffe7dcfa3b0
RBP: 00007ffe7dcfa3b0 R08: 00007ffe7dcfb3b0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe7dcfb4a0
R13: 00007fc623432048 R14: 0000000000051919 R15: 00007ffe7dcfc570
 </TASK>
syz-executor: attempt to access beyond end of device
loop0: rw=1, sector=2972, nr_sectors = 12 limit=0
gfs2: fsid=syz:syz.0: Error 10 writing to journal, jid=0
gfs2: fsid=syz:syz.0: about to withdraw this file system
gfs2: fsid=syz:syz.0: Journal recovery skipped for jid 0 until next mount.
gfs2: fsid=syz:syz.0: Glock dequeues delayed: 0
gfs2: fsid=syz:syz.0: File system withdrawn
CPU: 1 PID: 5770 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 gfs2_withdraw+0xb24/0x13d0 fs/gfs2/util.c:345
 gfs2_log_flush+0x1d90/0x2500 fs/gfs2/log.c:1157
 gfs2_kill_sb+0x5d/0x320 fs/gfs2/ops_fstype.c:1789
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc62339da57
Code: a2 c7 05 9c fc 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe7dcfa2f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007fc62339da57
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffe7dcfb4a0
RBP: 00007fc623432048 R08: 00000000000105a0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000202 R12: 00007ffe7dcfb4a0
R13: 00007fc623432048 R14: 00005555774704e8 R15: 00007ffe7dcfc570
 </TASK>