====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.179/5267 is trying to acquire lock: ffff888025468ae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xc0/0x6c0 fs/gfs2/quota.c:682 but task is already holding lock: ffff888055e2c918 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x28e/0x1a90 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+0x42/0x2d0 kernel/locking/rwsem.c:1520 __gfs2_iomap_get+0x164/0x1390 fs/gfs2/bmap.c:862 gfs2_iomap_get+0xeb/0x170 fs/gfs2/bmap.c:1413 bh_get+0x26d/0x780 fs/gfs2/quota.c:385 qdsb_get+0x21c/0x3c0 fs/gfs2/quota.c:522 gfs2_quota_hold+0x18d/0x5b0 fs/gfs2/quota.c:608 gfs2_quota_lock+0xa0/0x7f0 fs/gfs2/quota.c:1076 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline] alloc_dinode+0x170/0x4b0 fs/gfs2/inode.c:393 gfs2_create_inode+0xd17/0x1490 fs/gfs2/inode.c:712 gfs2_atomic_open+0xce/0x210 fs/gfs2/inode.c:1292 atomic_open fs/namei.c:3353 [inline] lookup_open fs/namei.c:3461 [inline] open_last_lookups fs/namei.c:3558 [inline] path_openat+0xe5d/0x2f10 fs/namei.c:3788 do_filp_open+0x1ee/0x420 fs/namei.c:3818 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_creat fs/open.c:1414 [inline] __se_sys_creat fs/open.c:1408 [inline] __x64_sys_creat+0x8c/0xb0 fs/open.c:1408 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/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:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 do_qc+0xc0/0x6c0 fs/gfs2/quota.c:682 gfs2_quota_change+0x293/0x7a0 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x18e1/0x20a0 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x4eb/0x1a90 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x15d/0x200 fs/gfs2/bmap.c:1426 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xffb/0x1d50 fs/gfs2/file.c:1331 gfs2_fallocate+0x36f/0x4b0 fs/gfs2/file.c:1395 vfs_fallocate+0x57b/0x6f0 fs/open.c:323 ksys_fallocate fs/open.c:346 [inline] __do_sys_fallocate fs/open.c:354 [inline] __se_sys_fallocate fs/open.c:352 [inline] __x64_sys_fallocate+0xbd/0x100 fs/open.c:352 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/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.8.179/5267: #0: ffff88804eeca460 (sb_writers#20){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3015 [inline] #0: ffff88804eeca460 (sb_writers#20){.+.+}-{0:0}, at: vfs_fallocate+0x4ee/0x6f0 fs/open.c:322 #1: ffff888055e2c480 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff888055e2c480 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: gfs2_fallocate+0x1c9/0x4b0 fs/gfs2/file.c:1374 #2: ffff88804eeca650 (sb_internal#4){.+.+}-{0:0}, at: gfs2_trans_begin+0x6b/0xe0 fs/gfs2/trans.c:118 #3: ffff888025469058 (&sdp->sd_log_flush_lock){++++}-{3:3}, at: __gfs2_trans_begin+0x533/0x8b0 fs/gfs2/trans.c:87 #4: ffff888055e2c918 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x28e/0x1a90 fs/gfs2/bmap.c:685 stack backtrace: CPU: 0 PID: 5267 Comm: syz.8.179 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 do_qc+0xc0/0x6c0 fs/gfs2/quota.c:682 gfs2_quota_change+0x293/0x7a0 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x18e1/0x20a0 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x4eb/0x1a90 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x15d/0x200 fs/gfs2/bmap.c:1426 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xffb/0x1d50 fs/gfs2/file.c:1331 gfs2_fallocate+0x36f/0x4b0 fs/gfs2/file.c:1395 vfs_fallocate+0x57b/0x6f0 fs/open.c:323 ksys_fallocate fs/open.c:346 [inline] __do_sys_fallocate fs/open.c:354 [inline] __se_sys_fallocate fs/open.c:352 [inline] __x64_sys_fallocate+0xbd/0x100 fs/open.c:352 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb9c679e0d9 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:00007fb9c76cc028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007fb9c6a25fa0 RCX: 00007fb9c679e0d9 RDX: 0000000000004000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007fb9c6835024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb9c6a26038 R14: 00007fb9c6a25fa0 R15: 00007fffed7a04d8