syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.167-syzkaller #0 Not tainted
------------------------------------------------------
syz.0.1/3709 is trying to acquire lock:
ffff888078c30ae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xc8/0x720 fs/gfs2/quota.c:678

but task is already holding lock:
ffff88805ed405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1514 [inline]
ffff88805ed405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x27e5/0x3ab0 fs/gfs2/bmap.c:1839

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ip->i_rw_mutex){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       __gfs2_iomap_get+0x178/0x1480 fs/gfs2/bmap.c:858
       gfs2_iomap_get fs/gfs2/bmap.c:1398 [inline]
       gfs2_block_map+0x292/0x830 fs/gfs2/bmap.c:1213
       bh_get+0x26d/0x6a0 fs/gfs2/quota.c:385
       qdsb_get+0x209/0x3b0 fs/gfs2/quota.c:518
       gfs2_quota_hold+0x19d/0x5c0 fs/gfs2/quota.c:604
       punch_hole+0xebd/0x3ab0 fs/gfs2/bmap.c:1800
       do_shrink+0x844/0x9b0 fs/gfs2/bmap.c:2020
       gfs2_setattr_size+0x151/0x8d0 fs/gfs2/bmap.c:2144
       gfs2_setattr+0x254/0x400 fs/gfs2/inode.c:2005
       notify_change+0xc6d/0xf50 fs/attr.c:505
       do_truncate+0x21c/0x300 fs/open.c:65
       handle_truncate fs/namei.c:3265 [inline]
       do_open fs/namei.c:3612 [inline]
       path_openat+0x28a3/0x2f20 fs/namei.c:3742
       do_filp_open+0x21c/0x460 fs/namei.c:3769
       do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_creat fs/open.c:1343 [inline]
       __se_sys_creat fs/open.c:1337 [inline]
       __x64_sys_creat+0x11f/0x160 fs/open.c:1337
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&sdp->sd_quota_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       do_qc+0xc8/0x720 fs/gfs2/quota.c:678
       gfs2_quota_change+0x2db/0x8c0 fs/gfs2/quota.c:1295
       punch_hole+0x3446/0x3ab0 fs/gfs2/bmap.c:1940
       do_shrink+0x844/0x9b0 fs/gfs2/bmap.c:2020
       gfs2_setattr_size+0x151/0x8d0 fs/gfs2/bmap.c:2144
       gfs2_setattr+0x254/0x400 fs/gfs2/inode.c:2005
       notify_change+0xc6d/0xf50 fs/attr.c:505
       do_truncate+0x21c/0x300 fs/open.c:65
       handle_truncate fs/namei.c:3265 [inline]
       do_open fs/namei.c:3612 [inline]
       path_openat+0x28a3/0x2f20 fs/namei.c:3742
       do_filp_open+0x21c/0x460 fs/namei.c:3769
       do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
       do_sys_open fs/open.c:1269 [inline]
       __do_sys_creat fs/open.c:1343 [inline]
       __se_sys_creat fs/open.c:1337 [inline]
       __x64_sys_creat+0x11f/0x160 fs/open.c:1337
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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 ***

5 locks held by syz.0.1/3709:
 #0: ffff888078f96460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377
 #1: ffff88805ed40150 (&sb->s_type->i_mutex_key#24){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff88805ed40150 (&sb->s_type->i_mutex_key#24){+.+.}-{3:3}, at: do_truncate+0x208/0x300 fs/open.c:63
 #2: ffff888078f96650 (sb_internal#4){.+.+}-{0:0}, at: gfs2_trans_begin+0x6d/0xe0 fs/gfs2/trans.c:118
 #3: ffff888078c310a8 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x55a/0x940 fs/gfs2/trans.c:87
 #4: ffff88805ed405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1514 [inline]
 #4: ffff88805ed405e8 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x27e5/0x3ab0 fs/gfs2/bmap.c:1839

stack backtrace:
CPU: 1 PID: 3709 Comm: syz.0.1 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 do_qc+0xc8/0x720 fs/gfs2/quota.c:678
 gfs2_quota_change+0x2db/0x8c0 fs/gfs2/quota.c:1295
 punch_hole+0x3446/0x3ab0 fs/gfs2/bmap.c:1940
 do_shrink+0x844/0x9b0 fs/gfs2/bmap.c:2020
 gfs2_setattr_size+0x151/0x8d0 fs/gfs2/bmap.c:2144
 gfs2_setattr+0x254/0x400 fs/gfs2/inode.c:2005
 notify_change+0xc6d/0xf50 fs/attr.c:505
 do_truncate+0x21c/0x300 fs/open.c:65
 handle_truncate fs/namei.c:3265 [inline]
 do_open fs/namei.c:3612 [inline]
 path_openat+0x28a3/0x2f20 fs/namei.c:3742
 do_filp_open+0x21c/0x460 fs/namei.c:3769
 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_creat fs/open.c:1343 [inline]
 __se_sys_creat fs/open.c:1337 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fcb31700ff9
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:00007fcb2fb58038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fcb318b9058 RCX: 00007fcb31700ff9
RDX: 0000000000000000 RSI: 000000000000004c RDI: 0000000020000100
RBP: 00007fcb31773296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fcb318b9058 R15: 00007ffc3f3320b8
 </TASK>