====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.239/5217 is trying to acquire lock: ffff0000f6a2cae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xbc/0x648 fs/gfs2/quota.c:682 but task is already holding lock: ffff0000f625c260 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x1f4/0x13f4 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+0x64/0x300 kernel/locking/rwsem.c:1520 __gfs2_iomap_get+0x114/0x1044 fs/gfs2/bmap.c:862 gfs2_iomap_get+0xd4/0x144 fs/gfs2/bmap.c:1413 bh_get+0x1e4/0x604 fs/gfs2/quota.c:385 qdsb_get+0x1d4/0x378 fs/gfs2/quota.c:522 gfs2_quota_hold+0x16c/0x558 fs/gfs2/quota.c:608 gfs2_quota_lock+0xbc/0x744 fs/gfs2/quota.c:1076 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline] __gfs2_fallocate+0x698/0x1758 fs/gfs2/file.c:1298 gfs2_fallocate+0x34c/0x494 fs/gfs2/file.c:1395 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290 file_ioctl fs/ioctl.c:-1 [inline] do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #0 (&sdp->sd_quota_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 do_qc+0xbc/0x648 fs/gfs2/quota.c:682 gfs2_quota_change+0x238/0x718 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x13b8/0x1ab8 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x388/0x13f4 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x134/0x1c4 fs/gfs2/bmap.c:1426 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xbd0/0x1758 fs/gfs2/file.c:1331 gfs2_fallocate+0x34c/0x494 fs/gfs2/file.c:1395 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290 file_ioctl fs/ioctl.c:-1 [inline] do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 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.4.239/5217: #0: ffff0000cd208460 (sb_writers#17){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3015 [inline] #0: ffff0000cd208460 (sb_writers#17){.+.+}-{0:0}, at: vfs_fallocate+0x434/0x5f4 fs/open.c:322 #1: ffff0000f625bdc8 (&sb->s_type->i_mutex_key#25){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff0000f625bdc8 (&sb->s_type->i_mutex_key#25){+.+.}-{3:3}, at: gfs2_fallocate+0x190/0x494 fs/gfs2/file.c:1374 #2: ffff0000cd208650 (sb_internal#5){.+.+}-{0:0}, at: gfs2_trans_begin+0xa8/0x114 fs/gfs2/trans.c:118 #3: ffff0000f6a2d058 (&sdp->sd_log_flush_lock){.+.+}-{3:3}, at: __gfs2_trans_begin+0x500/0x870 fs/gfs2/trans.c:87 #4: ffff0000f625c260 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x1f4/0x13f4 fs/gfs2/bmap.c:685 stack backtrace: CPU: 0 PID: 5217 Comm: syz.4.239 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x264/0x2f8 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 do_qc+0xbc/0x648 fs/gfs2/quota.c:682 gfs2_quota_change+0x238/0x718 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x13b8/0x1ab8 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x388/0x13f4 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x134/0x1c4 fs/gfs2/bmap.c:1426 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xbd0/0x1758 fs/gfs2/file.c:1331 gfs2_fallocate+0x34c/0x494 fs/gfs2/file.c:1395 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290 file_ioctl fs/ioctl.c:-1 [inline] do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585