loop5: detected capacity change from 0 to 512 EXT4-fs (loop5): mounted filesystem without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.5.368/6121 is trying to acquire lock: ffff0000fa618268 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x54/0x1c8 fs/quota/dquot.c:535 but task is already holding lock: ffff0000e17d3eb8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x720/0x160c fs/ext4/inode.c:674 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ei->i_data_sem/2){++++}-{3:3}: down_read+0x64/0x300 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x270/0x160c fs/ext4/inode.c:606 ext4_getblk+0x178/0x680 fs/ext4/inode.c:892 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948 ext4_quota_read+0x160/0x358 fs/ext4/super.c:7182 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x178/0xc2c fs/quota/quota_tree.c:671 find_tree_dqentry+0x4fc/0xc2c fs/quota/quota_tree.c:698 find_tree_dqentry+0x4fc/0xc2c fs/quota/quota_tree.c:698 find_tree_dqentry+0x4fc/0xc2c fs/quota/quota_tree.c:698 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x45c/0x748 fs/quota/quota_tree.c:736 v2_read_dquot+0xbc/0x118 fs/quota/quota_v2.c:336 dquot_acquire+0x108/0x4b8 fs/quota/dquot.c:491 ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6837 dqget+0x638/0xa98 fs/quota/dquot.c:1013 __dquot_initialize+0x280/0xb30 fs/quota/dquot.c:1542 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1604 ext4_process_orphan+0x5c/0x2c0 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0x964/0x1090 fs/ext4/orphan.c:472 __ext4_fill_super fs/ext4/super.c:5574 [inline] ext4_fill_super+0x5af8/0x63bc fs/ext4/super.c:5693 get_tree_bdev+0x35c/0x54c fs/super.c:1366 ext4_get_tree+0x28/0x38 fs/ext4/super.c:5723 vfs_get_tree+0x90/0x278 fs/super.c:1573 do_new_mount+0x228/0x804 fs/namespace.c:3078 path_mount+0x5ac/0xe6c fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 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 -> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}: down_read+0x64/0x300 kernel/locking/rwsem.c:1520 v2_read_dquot+0x4c/0x118 fs/quota/quota_v2.c:335 dquot_acquire+0x108/0x4b8 fs/quota/dquot.c:491 ext4_acquire_dquot+0x270/0x420 fs/ext4/super.c:6837 dqget+0x638/0xa98 fs/quota/dquot.c:1013 __dquot_initialize+0x2e4/0xb30 fs/quota/dquot.c:1542 dquot_initialize+0x24/0x34 fs/quota/dquot.c:1604 ext4_create+0x9c/0x410 fs/ext4/namei.c:2876 lookup_open fs/namei.c:3490 [inline] open_last_lookups fs/namei.c:3558 [inline] path_openat+0xda8/0x27a0 fs/namei.c:3788 do_filp_open+0x198/0x38c fs/namei.c:3818 do_sys_openat2+0x134/0x3fc fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __arm64_sys_openat+0x11c/0x150 fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 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 (&dquot->dq_lock){+.+.}-{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+0x2808/0x6634 kernel/locking/lockdep.c:5063 lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5676 __mutex_lock_common+0x1a0/0x1f3c kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 dquot_commit+0x54/0x1c8 fs/quota/dquot.c:535 ext4_write_dquot+0x1b4/0x320 fs/ext4/super.c:6817 ext4_mark_dquot_dirty+0xe8/0x150 fs/ext4/super.c:6894 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:440 __dquot_alloc_space+0x564/0xcfc fs/quota/dquot.c:1777 dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline] dquot_alloc_space include/linux/quotaops.h:306 [inline] dquot_alloc_block include/linux/quotaops.h:330 [inline] ext4_mb_new_blocks+0xd40/0x4244 fs/ext4/mballoc.c:5740 ext4_ext_map_blocks+0x1330/0x563c fs/ext4/extents.c:4361 ext4_map_blocks+0x7b0/0x160c fs/ext4/inode.c:681 ext4_getblk+0x178/0x680 fs/ext4/inode.c:892 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948 ext4_append+0x23c/0x488 fs/ext4/namei.c:83 ext4_init_new_dir+0x270/0x4f0 fs/ext4/namei.c:3030 ext4_mkdir+0x3b8/0xa28 fs/ext4/namei.c:3076 vfs_mkdir+0x314/0x4d8 fs/namei.c:4114 do_mkdirat+0x1b8/0x3ec fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4152 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 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: Chain exists of: &dquot->dq_lock --> &s->s_dquot.dqio_sem --> &ei->i_data_sem/2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->i_data_sem/2); lock(&s->s_dquot.dqio_sem); lock(&ei->i_data_sem/2); lock(&dquot->dq_lock); *** DEADLOCK *** 4 locks held by syz.5.368/6121: #0: ffff0000dcd92460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402 #1: ffff0000e1455e48 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline] #1: ffff0000e1455e48 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x1b0/0x3a8 fs/namei.c:3884 #2: ffff0000e17d3eb8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x720/0x160c fs/ext4/inode.c:674 #3: ffff80001568caa8 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 stack backtrace: CPU: 1 PID: 6121 Comm: syz.5.368 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 Call trace: dump_backtrace+0x1c4/0x1f0 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:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2808/0x6634 kernel/locking/lockdep.c:5063 lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5676 __mutex_lock_common+0x1a0/0x1f3c kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 dquot_commit+0x54/0x1c8 fs/quota/dquot.c:535 ext4_write_dquot+0x1b4/0x320 fs/ext4/super.c:6817 ext4_mark_dquot_dirty+0xe8/0x150 fs/ext4/super.c:6894 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:440 __dquot_alloc_space+0x564/0xcfc fs/quota/dquot.c:1777 dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline] dquot_alloc_space include/linux/quotaops.h:306 [inline] dquot_alloc_block include/linux/quotaops.h:330 [inline] ext4_mb_new_blocks+0xd40/0x4244 fs/ext4/mballoc.c:5740 ext4_ext_map_blocks+0x1330/0x563c fs/ext4/extents.c:4361 ext4_map_blocks+0x7b0/0x160c fs/ext4/inode.c:681 ext4_getblk+0x178/0x680 fs/ext4/inode.c:892 ext4_bread+0x3c/0x1a8 fs/ext4/inode.c:948 ext4_append+0x23c/0x488 fs/ext4/namei.c:83 ext4_init_new_dir+0x270/0x4f0 fs/ext4/namei.c:3030 ext4_mkdir+0x3b8/0xa28 fs/ext4/namei.c:3076 vfs_mkdir+0x314/0x4d8 fs/namei.c:4114 do_mkdirat+0x1b8/0x3ec fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4152 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 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 capability: warning: `syz.5.368' uses 32-bit capabilities (legacy support in use) FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 6121 Comm: syz.5.368 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 Call trace: dump_backtrace+0x1c4/0x1f0 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 fail_dump lib/fault-inject.c:52 [inline] should_fail_ex+0x3cc/0x524 lib/fault-inject.c:147 __should_failslab+0xc0/0x11c mm/failslab.c:44 should_failslab+0x10/0x28 mm/slab_common.c:1440 slab_pre_alloc_hook mm/slab.h:712 [inline] slab_alloc_node mm/slub.c:3279 [inline] kmem_cache_alloc_node+0x8c/0x344 mm/slub.c:3404 __alloc_skb+0x128/0x728 net/core/skbuff.c:505 alloc_skb include/linux/skbuff.h:1303 [inline] nlmsg_new include/net/netlink.h:998 [inline] genlmsg_new include/net/genetlink.h:434 [inline] quota_send_warning+0xb0/0x4f8 fs/quota/netlink.c:50 flush_warnings fs/quota/dquot.c:1314 [inline] __dquot_transfer+0x1a60/0x1d00 fs/quota/dquot.c:2152 dquot_transfer+0x590/0x72c fs/quota/dquot.c:2199 ext4_setattr+0x7ac/0x15e4 fs/ext4/inode.c:5527 notify_change+0xb5c/0xe20 fs/attr.c:499 chown_common+0x430/0x59c fs/open.c:736 vfs_fchown fs/open.c:804 [inline] ksys_fchown+0xe0/0x158 fs/open.c:815 __do_sys_fchown fs/open.c:823 [inline] __se_sys_fchown fs/open.c:821 [inline] __arm64_sys_fchown+0x7c/0x94 fs/open.c:821 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 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 VFS: Not enough memory to send quota warning.