====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.2555/12949 is trying to acquire lock: ffff8880721865e8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:532 but task is already holding lock: ffff88807210aaa8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x914/0x1a90 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_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 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] find_free_dqentry+0x68c/0xc30 fs/quota/quota_tree.c:318 do_insert_tree+0x717/0x1060 fs/quota/quota_tree.c:400 do_insert_tree+0x9b8/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9b8/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9b8/0x1060 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:497 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1010 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1539 ext4_setattr+0x2bf/0x1bc0 fs/ext4/inode.c:5504 notify_change+0xca0/0xf90 fs/attr.c:499 do_truncate+0x1ac/0x240 fs/open.c:65 vfs_truncate+0x262/0x2f0 fs/open.c:111 do_sys_truncate+0xf2/0x1c0 fs/open.c:134 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:488 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1010 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1539 ext4_set_acl+0x15e/0x5e0 fs/ext4/acl.c:237 set_posix_acl fs/posix_acl.c:1160 [inline] posix_acl_xattr_set+0x388/0x3f0 fs/posix_acl.c:1189 __vfs_setxattr+0x3d8/0x410 fs/xattr.c:182 __vfs_setxattr_noperm+0x126/0x5e0 fs/xattr.c:216 vfs_setxattr+0x167/0x2e0 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr+0x2a3/0x330 fs/xattr.c:617 path_setxattr+0x147/0x290 fs/xattr.c:636 __do_sys_setxattr fs/xattr.c:652 [inline] __se_sys_setxattr fs/xattr.c:648 [inline] __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:648 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:532 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817 mark_dquot_dirty fs/quota/dquot.c:397 [inline] mark_all_dquot_dirty+0x1e3/0x400 fs/quota/dquot.c:437 __dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1774 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+0xf55/0x44d0 fs/ext4/mballoc.c:5740 ext4_ext_map_blocks+0x18d1/0x6640 fs/ext4/extents.c:4361 ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681 ext4_alloc_file_blocks+0x378/0xb60 fs/ext4/extents.c:4545 ext4_fallocate+0x9ce/0x2000 fs/ext4/extents.c:4832 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: 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.8.2555/12949: #0: ffff88807e5a4460 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3015 [inline] #0: ffff88807e5a4460 (sb_writers#4){.+.+}-{0:0}, at: vfs_fallocate+0x4ee/0x6f0 fs/open.c:322 #1: ffff88807210ac20 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff88807210ac20 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_fallocate+0x219/0x2000 fs/ext4/extents.c:4806 #2: ffff88807210aaa8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 #3: ffffffff8cc74e68 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8cc74e68 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #3: ffffffff8cc74e68 (dquot_srcu){....}-{0:0}, at: __dquot_alloc_space+0x16e/0xe50 fs/quota/dquot.c:1738 stack backtrace: CPU: 1 PID: 12949 Comm: syz.8.2555 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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:532 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817 mark_dquot_dirty fs/quota/dquot.c:397 [inline] mark_all_dquot_dirty+0x1e3/0x400 fs/quota/dquot.c:437 __dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1774 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+0xf55/0x44d0 fs/ext4/mballoc.c:5740 ext4_ext_map_blocks+0x18d1/0x6640 fs/ext4/extents.c:4361 ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681 ext4_alloc_file_blocks+0x378/0xb60 fs/ext4/extents.c:4545 ext4_fallocate+0x9ce/0x2000 fs/ext4/extents.c:4832 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: 0033:0x7f7f89b9de59 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:00007f7f8aaff028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f7f89e25fa0 RCX: 00007f7f89b9de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007f7f89c33e6f R08: 0000000000000000 R09: 0000000000000000 R10: 00000000001000f4 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7f89e26038 R14: 00007f7f89e25fa0 R15: 00007fff319de9d8