====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.506/7965 is trying to acquire lock: ffff88806d7ccae8 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xaf/0x670 fs/gfs2/quota.c:689 but task is already holding lock: ffff88805c8fa0c8 (&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 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] alloc_dinode+0x182/0x5d0 fs/gfs2/inode.c:409 gfs2_create_inode+0xdb6/0x1540 fs/gfs2/inode.c:739 gfs2_atomic_open+0xd2/0x220 fs/gfs2/inode.c:1315 atomic_open fs/namei.c:3359 [inline] lookup_open fs/namei.c:3467 [inline] open_last_lookups fs/namei.c:3564 [inline] path_openat+0xf49/0x3230 fs/namei.c:3794 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 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 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 ksys_fallocate fs/open.c:347 [inline] __do_sys_fallocate fs/open.c:355 [inline] __se_sys_fallocate fs/open.c:353 [inline] __x64_sys_fallocate+0xc1/0x110 fs/open.c:353 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 *** 5 locks held by syz.2.506/7965: #0: ffff888031346418 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2711 [inline] #0: ffff888031346418 (sb_writers#22){.+.+}-{0:0}, at: vfs_fallocate+0x4fb/0x700 fs/open.c:323 #1: ffff88805c8f9c40 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #1: ffff88805c8f9c40 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: gfs2_fallocate+0x1d0/0x4c0 fs/gfs2/file.c:1374 #2: ffff888031346608 (sb_internal#5){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118 #3: ffff88806d7cd060 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x517/0x890 fs/gfs2/trans.c:87 #4: ffff88805c8fa0c8 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x290/0x1aa0 fs/gfs2/bmap.c:685 stack backtrace: CPU: 0 PID: 7965 Comm: syz.2.506 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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 ksys_fallocate fs/open.c:347 [inline] __do_sys_fallocate fs/open.c:355 [inline] __se_sys_fallocate fs/open.c:353 [inline] __x64_sys_fallocate+0xc1/0x110 fs/open.c:353 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: 0033:0x7f09a099c819 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:00007f09a1823028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f09a0c15fa0 RCX: 00007f09a099c819 RDX: 0000000000007351 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007f09a0a32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000008001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f09a0c16038 R14: 00007f09a0c15fa0 R15: 00007ffc45455cb8