gfs2: fsid=syz:syz.0: found 1 quota changes
capability: warning: `syz.3.31' uses 32-bit capabilities (legacy support in use)
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.31/4393 is trying to acquire lock:
ffff888078df8ae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xca/0x730 fs/gfs2/quota.c:678

but task is already holding lock:
ffff88805d8cd080 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x271/0x1a20 fs/gfs2/bmap.c:681

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+0x44/0x2e0 kernel/locking/rwsem.c:1498
       __gfs2_iomap_get+0x155/0x13e0 fs/gfs2/bmap.c:858
       gfs2_iomap_get fs/gfs2/bmap.c:1398 [inline]
       gfs2_block_map+0x229/0x670 fs/gfs2/bmap.c:1213
       bh_get+0x227/0x5f0 fs/gfs2/quota.c:385
       qdsb_get+0x21c/0x3c0 fs/gfs2/quota.c:518
       gfs2_quota_hold+0x194/0x5d0 fs/gfs2/quota.c:604
       gfs2_quota_lock+0xa0/0x7d0 fs/gfs2/quota.c:1076
       gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
       alloc_dinode+0x164/0x4f0 fs/gfs2/inode.c:402
       gfs2_create_inode+0xc22/0x13b0 fs/gfs2/inode.c:721
       gfs2_atomic_open+0xce/0x210 fs/gfs2/inode.c:1296
       atomic_open fs/namei.c:3333 [inline]
       lookup_open fs/namei.c:3441 [inline]
       open_last_lookups fs/namei.c:3540 [inline]
       path_openat+0xe6d/0x2f30 fs/namei.c:3747
       do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
       do_sys_openat2+0x142/0x4a0 fs/open.c:1255
       do_sys_open fs/open.c:1271 [inline]
       __do_sys_openat fs/open.c:1287 [inline]
       __se_sys_openat fs/open.c:1282 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1282
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 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 kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1eb/0x2390 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+0xca/0x730 fs/gfs2/quota.c:678
       gfs2_quota_change+0x2f5/0x8e0 fs/gfs2/quota.c:1295
       gfs2_alloc_blocks+0x195e/0x2110 fs/gfs2/rgrp.c:2504
       __gfs2_iomap_alloc+0x4d1/0x1a20 fs/gfs2/bmap.c:707
       gfs2_iomap_begin_write fs/gfs2/bmap.c:1049 [inline]
       gfs2_iomap_begin+0xacf/0x1250 fs/gfs2/bmap.c:1114
       iomap_iter+0x620/0xdb0 fs/iomap/iter.c:74
       iomap_file_buffered_write+0x17e/0x5b0 fs/iomap/buffered-io.c:814
       gfs2_file_buffered_write+0x470/0x900 fs/gfs2/file.c:1058
       gfs2_file_write_iter+0x467/0x11d0 fs/gfs2/file.c:1166
       do_iter_readv_writev+0x497/0x600 fs/read_write.c:-1
       do_iter_write+0x205/0x7b0 fs/read_write.c:855
       vfs_writev fs/read_write.c:928 [inline]
       do_pwritev+0x204/0x340 fs/read_write.c:1025
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 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.3.31/4393:
 #0: ffff888078714460 (sb_writers#19){.+.+}-{0:0}, at: vfs_writev fs/read_write.c:927 [inline]
 #0: ffff888078714460 (sb_writers#19){.+.+}-{0:0}, at: do_pwritev+0x1f2/0x340 fs/read_write.c:1025
 #1: ffff88805d8ccbe8 (&sb->s_type->i_mutex_key#25){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88805d8ccbe8 (&sb->s_type->i_mutex_key#25){+.+.}-{3:3}, at: gfs2_file_write_iter+0x33b/0x11d0 fs/gfs2/file.c:1123
 #2: ffff888078714650 (sb_internal#2){.+.+}-{0:0}, at: gfs2_trans_begin+0x6b/0xe0 fs/gfs2/trans.c:118
 #3: ffff888078df90a8 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x50f/0x880 fs/gfs2/trans.c:87
 #4: ffff88805d8cd080 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x271/0x1a20 fs/gfs2/bmap.c:681

stack backtrace:
CPU: 1 PID: 4393 Comm: syz.3.31 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 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+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1eb/0x2390 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+0xca/0x730 fs/gfs2/quota.c:678
 gfs2_quota_change+0x2f5/0x8e0 fs/gfs2/quota.c:1295
 gfs2_alloc_blocks+0x195e/0x2110 fs/gfs2/rgrp.c:2504
 __gfs2_iomap_alloc+0x4d1/0x1a20 fs/gfs2/bmap.c:707
 gfs2_iomap_begin_write fs/gfs2/bmap.c:1049 [inline]
 gfs2_iomap_begin+0xacf/0x1250 fs/gfs2/bmap.c:1114
 iomap_iter+0x620/0xdb0 fs/iomap/iter.c:74
 iomap_file_buffered_write+0x17e/0x5b0 fs/iomap/buffered-io.c:814
 gfs2_file_buffered_write+0x470/0x900 fs/gfs2/file.c:1058
 gfs2_file_write_iter+0x467/0x11d0 fs/gfs2/file.c:1166
 do_iter_readv_writev+0x497/0x600 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_pwritev+0x204/0x340 fs/read_write.c:1025
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe103f76749
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:00007fe1021dd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007fe1041ccfa0 RCX: 00007fe103f76749
RDX: 0000000000000001 RSI: 0000200000000200 RDI: 0000000000000004
RBP: 00007fe103ffaf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e73 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe1041cd038 R14: 00007fe1041ccfa0 R15: 00007ffc4bb41828
 </TASK>