loop9: detected capacity change from 0 to 512 EXT4-fs (loop9): mounted filesystem without journal. Quota mode: writeback. ext4 filesystem being mounted at /132/bus supports timestamps until 2038-01-19 (0x7fffffff) ====================================================== WARNING: possible circular locking dependency detected 6.1.141-syzkaller #0 Not tainted ------------------------------------------------------ syz.9.1787/13411 is trying to acquire lock: ffff8880557345e8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 but task is already holding lock: ffff88805a2ad2c8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x903/0x1b60 fs/ext4/inode.c:672 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+0x316/0x1b60 fs/ext4/inode.c:604 ext4_getblk+0x1ab/0x6d0 fs/ext4/inode.c:890 ext4_bread+0x26/0x170 fs/ext4/inode.c:946 ext4_quota_read+0x180/0x380 fs/ext4/super.c:7155 read_blk fs/quota/quota_tree.c:61 [inline] find_tree_dqentry+0x1cd/0xf30 fs/quota/quota_tree.c:671 find_tree_dqentry+0x6b0/0xf30 fs/quota/quota_tree.c:698 find_tree_dqentry+0x6b0/0xf30 fs/quota/quota_tree.c:698 find_tree_dqentry+0x6b0/0xf30 fs/quota/quota_tree.c:698 find_dqentry fs/quota/quota_tree.c:716 [inline] qtree_read_dquot+0x558/0x7f0 fs/quota/quota_tree.c:736 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:336 dquot_acquire+0x152/0x520 fs/quota/dquot.c:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6810 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x328/0xcb0 fs/quota/dquot.c:1517 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:329 ext4_orphan_cleanup+0xbd3/0x1400 fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5535 [inline] ext4_fill_super+0x7b78/0x8110 fs/ext4/super.c:5666 get_tree_bdev+0x3f1/0x610 fs/super.c:1366 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x24a/0xa40 fs/namespace.c:3054 do_mount fs/namespace.c:3397 [inline] __do_sys_mount fs/namespace.c:3605 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3582 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 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:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6810 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x328/0xcb0 fs/quota/dquot.c:1517 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:329 ext4_orphan_cleanup+0xbd3/0x1400 fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5535 [inline] ext4_fill_super+0x7b78/0x8110 fs/ext4/super.c:5666 get_tree_bdev+0x3f1/0x610 fs/super.c:1366 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x24a/0xa40 fs/namespace.c:3054 do_mount fs/namespace.c:3397 [inline] __do_sys_mount fs/namespace.c:3605 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3582 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&dquot->dq_lock){+.+.}-{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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6790 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline] dquot_alloc_space include/linux/quotaops.h:313 [inline] dquot_alloc_block include/linux/quotaops.h:337 [inline] ext4_mb_new_blocks+0xf74/0x4720 fs/ext4/mballoc.c:5727 ext4_ext_map_blocks+0x143c/0x66d0 fs/ext4/extents.c:4339 ext4_map_blocks+0x9d1/0x1b60 fs/ext4/inode.c:679 _ext4_get_block+0x1d7/0x4e0 fs/ext4/inode.c:822 ext4_block_write_begin+0x637/0x12f0 fs/ext4/inode.c:1124 ext4_write_begin+0x624/0xf50 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x304/0x950 fs/ext4/inode.c:3000 generic_perform_write+0x2db/0x560 mm/filemap.c:3846 ext4_buffered_write_iter+0x11a/0x3e0 fs/ext4/file.c:285 ext4_file_write_iter+0x1d6/0x16e0 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x44c/0x960 fs/read_write.c:584 ksys_write+0x143/0x240 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 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 *** 5 locks held by syz.9.1787/13411: #0: ffff88801f3725e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1040 #1: ffff88807add0460 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580 #2: ffff88805a2ad440 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #2: ffff88805a2ad440 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_buffered_write_iter+0xa1/0x3e0 fs/ext4/file.c:279 #3: ffff88805a2ad2c8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x903/0x1b60 fs/ext4/inode.c:672 #4: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #4: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: __dquot_alloc_space+0x173/0xe60 fs/quota/dquot.c:1716 stack backtrace: CPU: 0 PID: 13411 Comm: syz.9.1787 Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 check_noncircular+0x274/0x310 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6790 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline] dquot_alloc_space include/linux/quotaops.h:313 [inline] dquot_alloc_block include/linux/quotaops.h:337 [inline] ext4_mb_new_blocks+0xf74/0x4720 fs/ext4/mballoc.c:5727 ext4_ext_map_blocks+0x143c/0x66d0 fs/ext4/extents.c:4339 ext4_map_blocks+0x9d1/0x1b60 fs/ext4/inode.c:679 _ext4_get_block+0x1d7/0x4e0 fs/ext4/inode.c:822 ext4_block_write_begin+0x637/0x12f0 fs/ext4/inode.c:1124 ext4_write_begin+0x624/0xf50 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x304/0x950 fs/ext4/inode.c:3000 generic_perform_write+0x2db/0x560 mm/filemap.c:3846 ext4_buffered_write_iter+0x11a/0x3e0 fs/ext4/file.c:285 ext4_file_write_iter+0x1d6/0x16e0 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x44c/0x960 fs/read_write.c:584 ksys_write+0x143/0x240 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f548a98e929 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:00007f548b8e8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f548abb5fa0 RCX: 00007f548a98e929 RDX: 000000000000fcb5 RSI: 0000200000000380 RDI: 0000000000000006 RBP: 00007f548aa10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f548abb5fa0 R15: 00007ffff2732eb8