====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor/4274 is trying to acquire lock: ffff888055396968 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 but task is already holding lock: ffff88805523f0e0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x9ae/0x12a0 fs/ext4/inode.c:4297 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+0x42/0x2d0 kernel/locking/rwsem.c:1520 ext4_map_blocks+0x338/0x1a90 fs/ext4/inode.c:606 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_write+0x237/0x580 fs/ext4/super.c:7228 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x2dc/0x630 fs/quota/quota_tree.c:136 do_insert_tree+0x22b/0x1060 fs/quota/quota_tree.c:347 do_insert_tree+0x9f5/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9f5/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9f5/0x1060 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x49b/0x5d0 fs/quota/quota_tree.c:451 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:361 dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:500 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542 ext4_file_open+0x2da/0x6f0 fs/ext4/file.c:869 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3791 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_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 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 -> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}: down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520 v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:335 dquot_acquire+0x152/0x520 fs/quota/dquot.c:491 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 dquot_set_dqblk+0x27/0xfb0 fs/quota/dquot.c:2858 quota_setquota+0x4d6/0x590 fs/quota/quota.c:310 __do_sys_quotactl fs/quota/quota.c:960 [inline] __se_sys_quotactl+0x28b/0x6f0 fs/quota/quota.c:916 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 (&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+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 dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440 __dquot_free_space+0x7f8/0xbc0 fs/quota/dquot.c:1967 dquot_free_space_nodirty include/linux/quotaops.h:372 [inline] dquot_free_space include/linux/quotaops.h:377 [inline] dquot_free_block include/linux/quotaops.h:388 [inline] ext4_mb_clear_bb fs/ext4/mballoc.c:6153 [inline] ext4_free_blocks+0x1be5/0x26a0 fs/ext4/mballoc.c:6283 ext4_remove_blocks fs/ext4/extents.c:2523 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2707 [inline] ext4_ext_remove_space+0x22ba/0x43d0 fs/ext4/extents.c:2955 ext4_ext_truncate+0x213/0x370 fs/ext4/extents.c:4491 ext4_truncate+0xa5b/0x12a0 fs/ext4/inode.c:4302 ext4_evict_inode+0xb21/0x10e0 fs/ext4/inode.c:288 evict+0x4b6/0x8b0 fs/inode.c:705 do_unlinkat+0x388/0x580 fs/namei.c:4405 __do_sys_unlink fs/namei.c:4446 [inline] __se_sys_unlink fs/namei.c:4444 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4444 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: 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-executor/4274: #0: ffff8880769b0460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff8880769b0650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline] #1: ffff8880769b0650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:2013 [inline] #1: ffff8880769b0650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x431/0x10e0 fs/ext4/inode.c:242 #2: ffff88805523f0e0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x9ae/0x12a0 fs/ext4/inode.c:4297 #3: ffffffff8cc750a8 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8cc750a8 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #3: ffffffff8cc750a8 (dquot_srcu){....}-{0:0}, at: __dquot_free_space+0x172/0xbc0 fs/quota/dquot.c:1940 stack backtrace: CPU: 1 PID: 4274 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 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 dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440 __dquot_free_space+0x7f8/0xbc0 fs/quota/dquot.c:1967 dquot_free_space_nodirty include/linux/quotaops.h:372 [inline] dquot_free_space include/linux/quotaops.h:377 [inline] dquot_free_block include/linux/quotaops.h:388 [inline] ext4_mb_clear_bb fs/ext4/mballoc.c:6153 [inline] ext4_free_blocks+0x1be5/0x26a0 fs/ext4/mballoc.c:6283 ext4_remove_blocks fs/ext4/extents.c:2523 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2707 [inline] ext4_ext_remove_space+0x22ba/0x43d0 fs/ext4/extents.c:2955 ext4_ext_truncate+0x213/0x370 fs/ext4/extents.c:4491 ext4_truncate+0xa5b/0x12a0 fs/ext4/inode.c:4302 ext4_evict_inode+0xb21/0x10e0 fs/ext4/inode.c:288 evict+0x4b6/0x8b0 fs/inode.c:705 do_unlinkat+0x388/0x580 fs/namei.c:4405 __do_sys_unlink fs/namei.c:4446 [inline] __se_sys_unlink fs/namei.c:4444 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4444 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: 0033:0x7f5e1d19cf87 Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffcd1667808 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5e1d19cf87 RDX: 00007ffcd1667830 RSI: 00007ffcd16678c0 RDI: 00007ffcd16678c0 RBP: 00007ffcd16678c0 R08: 00007ffcd16688c0 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffcd16689b0 R13: 00007f5e1d23330a R14: 000000000002e570 R15: 00007ffcd1669a80 EXT4-fs (loop2): unmounting filesystem.