====================================================== WARNING: possible circular locking dependency detected 5.15.186-syzkaller #0 Not tainted ------------------------------------------------------ syz.2.491/6646 is trying to acquire lock: ffff888074b1c268 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 but task is already holding lock: ffff88805fb95c30 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x8b2/0x1b30 fs/ext4/inode.c:666 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+0x44/0x2e0 kernel/locking/rwsem.c:1498 ext4_map_blocks+0x32f/0x1b30 fs/ext4/inode.c:598 ext4_getblk+0x16d/0x630 fs/ext4/inode.c:870 ext4_bread+0x26/0x180 fs/ext4/inode.c:923 ext4_quota_write+0x230/0x570 fs/ext4/super.c:6594 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x387/0x7d0 fs/quota/quota_tree.c:125 do_insert_tree+0x214/0x1970 fs/quota/quota_tree.c:335 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 dq_insert_tree fs/quota/quota_tree.c:392 [inline] qtree_write_dquot+0x361/0x4b0 fs/quota/quota_tree.c:411 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:358 dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:472 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6203 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x328/0xcb0 fs/quota/dquot.c:1517 add_dquot_ref+0x2b4/0x380 fs/quota/dquot.c:1060 dquot_load_quota_sb+0x875/0xac0 fs/quota/dquot.c:2475 dquot_load_quota_inode+0x2d8/0x5d0 fs/quota/dquot.c:2500 ext4_quota_enable fs/ext4/super.c:6425 [inline] ext4_enable_quotas+0x4ab/0xb50 fs/ext4/super.c:6451 ext4_remount+0x1a10/0x2690 fs/ext4/super.c:5993 reconfigure_super+0x219/0x880 fs/super.c:938 vfs_fsconfig_locked+0x18d/0x3f0 fs/fsopen.c:254 __do_sys_fsconfig fs/fsopen.c:439 [inline] __se_sys_fsconfig+0x61b/0x750 fs/fsopen.c:314 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}: down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332 dquot_acquire+0x152/0x520 fs/quota/dquot.c:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6203 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x3b6/0xcb0 fs/quota/dquot.c:1517 ext4_create+0x8c/0x460 fs/ext4/namei.c:2876 lookup_open fs/namei.c:3462 [inline] open_last_lookups fs/namei.c:3532 [inline] path_openat+0x11e1/0x2f30 fs/namei.c:3739 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769 do_sys_openat2+0x142/0x4a0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_creat fs/open.c:1345 [inline] __se_sys_creat fs/open.c:1339 [inline] __x64_sys_creat+0x8c/0xb0 fs/open.c:1339 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&dquot->dq_lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6183 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:297 [inline] dquot_alloc_space include/linux/quotaops.h:310 [inline] dquot_alloc_block include/linux/quotaops.h:334 [inline] ext4_mb_new_blocks+0xf68/0x4940 fs/ext4/mballoc.c:5739 ext4_ext_map_blocks+0x146f/0x64e0 fs/ext4/extents.c:4341 ext4_map_blocks+0x981/0x1b30 fs/ext4/inode.c:673 ext4_alloc_file_blocks+0x370/0xb50 fs/ext4/extents.c:4528 ext4_fallocate+0x999/0x1ee0 fs/ext4/extents.c:4815 vfs_fallocate+0x587/0x6f0 fs/open.c:308 ksys_fallocate fs/open.c:331 [inline] __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0xbd/0x100 fs/open.c:337 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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.2.491/6646: #0: ffff888062cc2460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3042 [inline] #0: ffff888062cc2460 (sb_writers#5){.+.+}-{0:0}, at: vfs_fallocate+0x4f4/0x6f0 fs/open.c:307 #1: ffff88805fb95da8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #1: ffff88805fb95da8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_fallocate+0x21c/0x1ee0 fs/ext4/extents.c:4789 #2: ffff88805fb95c30 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x8b2/0x1b30 fs/ext4/inode.c:666 #3: ffffffff8c23fd98 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 0 PID: 6646 Comm: syz.2.491 Not tainted 5.15.186-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6183 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:297 [inline] dquot_alloc_space include/linux/quotaops.h:310 [inline] dquot_alloc_block include/linux/quotaops.h:334 [inline] ext4_mb_new_blocks+0xf68/0x4940 fs/ext4/mballoc.c:5739 ext4_ext_map_blocks+0x146f/0x64e0 fs/ext4/extents.c:4341 ext4_map_blocks+0x981/0x1b30 fs/ext4/inode.c:673 ext4_alloc_file_blocks+0x370/0xb50 fs/ext4/extents.c:4528 ext4_fallocate+0x999/0x1ee0 fs/ext4/extents.c:4815 vfs_fallocate+0x587/0x6f0 fs/open.c:308 ksys_fallocate fs/open.c:331 [inline] __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0xbd/0x100 fs/open.c:337 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f1e76efb929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1e74d63038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f1e77122fa0 RCX: 00007f1e76efb929 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f1e76f7db39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000008000c62 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1e77122fa0 R15: 00007ffdd6ab7f28