gfs2: fsid=syz:syz.0: first mount done, others may mount ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.516/8108 is trying to acquire lock: ffff88802ed34ae8 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xaf/0x670 fs/gfs2/quota.c:689 but task is already holding lock: ffff888051b9cfd0 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x290/0x1aa0 fs/gfs2/bmap.c:685 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 qd_fish fs/gfs2/quota.c:496 [inline] gfs2_quota_sync+0x33a/0x5a0 fs/gfs2/quota.c:1335 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:670 sync_filesystem+0xea/0x220 fs/sync.c:56 gfs2_reconfigure+0xbb/0xb10 fs/gfs2/ops_fstype.c:1564 reconfigure_super+0x21e/0x8a0 fs/super.c:1151 vfs_cmd_reconfigure fs/fsopen.c:273 [inline] vfs_fsconfig_locked+0x16c/0x320 fs/fsopen.c:302 __do_sys_fsconfig fs/fsopen.c:481 [inline] __se_sys_fsconfig+0x70d/0x850 fs/fsopen.c:355 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 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 gfs2_alloc_blocks+0x18b6/0x2070 fs/gfs2/rgrp.c:2496 __gfs2_iomap_alloc+0x4d5/0x1aa0 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x161/0x200 fs/gfs2/bmap.c:1440 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xfe3/0x1cd0 fs/gfs2/file.c:1331 gfs2_fallocate+0x374/0x4c0 fs/gfs2/file.c:1395 vfs_fallocate+0x58e/0x700 fs/open.c:324 ioctl_preallocate fs/ioctl.c:291 [inline] file_ioctl fs/ioctl.c:331 [inline] do_vfs_ioctl+0x19f6/0x1cc0 fs/ioctl.c:850 __do_sys_ioctl fs/ioctl.c:869 [inline] __se_sys_ioctl+0x83/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 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 *** 5 locks held by syz.3.516/8108: #0: ffff888049d3c418 (sb_writers#25){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2711 [inline] #0: ffff888049d3c418 (sb_writers#25){.+.+}-{0:0}, at: vfs_fallocate+0x4fb/0x700 fs/open.c:323 #1: ffff888051b9cb48 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff888051b9cb48 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: gfs2_fallocate+0x1d0/0x4c0 fs/gfs2/file.c:1374 #2: ffff888049d3c608 (sb_internal#5){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118 #3: ffff88802ed35060 (&sdp->sd_log_flush_lock){++++}-{3:3}, at: __gfs2_trans_begin+0x517/0x890 fs/gfs2/trans.c:87 #4: ffff888051b9cfd0 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x290/0x1aa0 fs/gfs2/bmap.c:685 stack backtrace: CPU: 1 PID: 8108 Comm: syz.3.516 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: 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 gfs2_alloc_blocks+0x18b6/0x2070 fs/gfs2/rgrp.c:2496 __gfs2_iomap_alloc+0x4d5/0x1aa0 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x161/0x200 fs/gfs2/bmap.c:1440 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xfe3/0x1cd0 fs/gfs2/file.c:1331 gfs2_fallocate+0x374/0x4c0 fs/gfs2/file.c:1395 vfs_fallocate+0x58e/0x700 fs/open.c:324 ioctl_preallocate fs/ioctl.c:291 [inline] file_ioctl fs/ioctl.c:331 [inline] do_vfs_ioctl+0x19f6/0x1cc0 fs/ioctl.c:850 __do_sys_ioctl fs/ioctl.c:869 [inline] __se_sys_ioctl+0x83/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f7a5fd9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7a60c5f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7a60015fa0 RCX: 00007f7a5fd9ce59 RDX: 0000200000000240 RSI: 0000000040305828 RDI: 0000000000000004 RBP: 00007f7a5fe32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7a60016038 R14: 00007f7a60015fa0 R15: 00007ffde6945288