====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0 Not tainted ------------------------------------------------------ syz.0.0/5316 is trying to acquire lock: ffff8880346b2450 (&q->limits_lock){+.+.}-{4:4}, at: queue_limits_start_update include/linux/blkdev.h:949 [inline] ffff8880346b2450 (&q->limits_lock){+.+.}-{4:4}, at: loop_reconfigure_limits+0x43f/0x900 drivers/block/loop.c:998 but task is already holding lock: ffff8880346b1e00 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: loop_set_block_size drivers/block/loop.c:1472 [inline] ffff8880346b1e00 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: lo_simple_ioctl drivers/block/loop.c:1496 [inline] ffff8880346b1e00 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: lo_ioctl+0x1344/0x1f50 drivers/block/loop.c:1559 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&q->q_usage_counter(io)#17){++++}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1536/0x2390 block/blk-mq.c:3092 __submit_bio+0x2c6/0x560 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739 xfs_buf_ioapply_map+0x461/0x5d0 fs/xfs/xfs_buf.c:1586 _xfs_buf_ioapply+0x307/0x660 fs/xfs/xfs_buf.c:1674 __xfs_buf_submit+0x34f/0x7e0 fs/xfs/xfs_buf.c:1758 xfs_buf_submit fs/xfs/xfs_buf.c:61 [inline] _xfs_buf_read fs/xfs/xfs_buf.c:809 [inline] xfs_buf_read_map+0x431/0xa50 fs/xfs/xfs_buf.c:873 xfs_trans_read_buf_map+0x260/0xab0 fs/xfs/xfs_trans_buf.c:304 xfs_trans_read_buf fs/xfs/xfs_trans.h:213 [inline] xfs_read_agf+0x2dc/0x630 fs/xfs/libxfs/xfs_alloc.c:3378 xfs_alloc_read_agf+0x196/0xbe0 fs/xfs/libxfs/xfs_alloc.c:3413 xfs_alloc_fix_freelist+0x608/0x1bc0 fs/xfs/libxfs/xfs_alloc.c:2877 xfs_alloc_vextent_prepare_ag+0xf9/0x6b0 fs/xfs/libxfs/xfs_alloc.c:3543 xfs_alloc_vextent_iterate_ags+0x141/0x950 fs/xfs/libxfs/xfs_alloc.c:3727 xfs_alloc_vextent_start_ag+0x3f6/0x950 fs/xfs/libxfs/xfs_alloc.c:3816 xfs_bmap_btalloc_best_length fs/xfs/libxfs/xfs_bmap.c:3766 [inline] xfs_bmap_btalloc fs/xfs/libxfs/xfs_bmap.c:3811 [inline] xfs_bmapi_allocate+0x18fa/0x3450 fs/xfs/libxfs/xfs_bmap.c:4224 xfs_bmapi_write+0xbac/0x1b40 fs/xfs/libxfs/xfs_bmap.c:4553 xfs_dquot_disk_alloc+0x5f4/0xe20 fs/xfs/xfs_dquot.c:355 xfs_qm_dqread+0x1a3/0x630 fs/xfs/xfs_dquot.c:694 xfs_qm_dqget+0x2bb/0x6f0 fs/xfs/xfs_dquot.c:906 xfs_qm_quotacheck_dqadjust+0xea/0x5a0 fs/xfs/xfs_qm.c:1297 xfs_qm_dqusage_adjust+0x778/0x850 fs/xfs/xfs_qm.c:1433 xfs_iwalk_ag_recs+0x4e3/0x820 fs/xfs/xfs_iwalk.c:209 xfs_iwalk_run_callbacks+0x218/0x470 fs/xfs/xfs_iwalk.c:370 xfs_iwalk_ag+0xa9a/0xbb0 fs/xfs/xfs_iwalk.c:476 xfs_iwalk_ag_work+0xfb/0x1b0 fs/xfs/xfs_iwalk.c:625 xfs_pwork_work+0x7f/0x190 fs/xfs/xfs_pwork.c:47 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #3 (&xfs_nondir_ilock_class){++++}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693 xfs_reclaim_inode fs/xfs/xfs_icache.c:1037 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1729 [inline] xfs_icwalk_ag+0x1211/0x1ac0 fs/xfs/xfs_icache.c:1811 xfs_icwalk fs/xfs/xfs_icache.c:1859 [inline] xfs_reclaim_inodes_nr+0x2b0/0x390 fs/xfs/xfs_icache.c:1103 super_cache_scan+0x40f/0x4b0 fs/super.c:227 do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437 shrink_slab+0x1093/0x14d0 mm/shrinker.c:664 shrink_one+0x43b/0x850 mm/vmscan.c:4836 shrink_many mm/vmscan.c:4897 [inline] lru_gen_shrink_node mm/vmscan.c:4975 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5956 kswapd_shrink_node mm/vmscan.c:6785 [inline] balance_pgdat mm/vmscan.c:6977 [inline] kswapd+0x1ca9/0x36f0 mm/vmscan.c:7246 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #2 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __fs_reclaim_acquire mm/page_alloc.c:3851 [inline] fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3865 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4055 [inline] slab_alloc_node mm/slub.c:4133 [inline] __do_kmalloc_node mm/slub.c:4282 [inline] __kmalloc_node_noprof+0xb2/0x4d0 mm/slub.c:4289 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:650 sbitmap_init_node+0x2d4/0x670 lib/sbitmap.c:132 scsi_realloc_sdev_budget_map+0x2a7/0x460 drivers/scsi/scsi_scan.c:246 scsi_add_lun drivers/scsi/scsi_scan.c:1106 [inline] scsi_probe_and_add_lun+0x3173/0x4bd0 drivers/scsi/scsi_scan.c:1287 __scsi_add_device+0x228/0x2f0 drivers/scsi/scsi_scan.c:1622 ata_scsi_scan_host+0x236/0x740 drivers/ata/libata-scsi.c:4575 async_run_entry_fn+0xa8/0x420 kernel/async.c:129 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #1 (&q->q_usage_counter(queue)#20){++++}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 blk_queue_enter+0xe1/0x600 block/blk-core.c:328 blk_mq_alloc_request+0x4fa/0xaa0 block/blk-mq.c:652 scsi_alloc_request drivers/scsi/scsi_lib.c:1222 [inline] scsi_execute_cmd+0x177/0x1090 drivers/scsi/scsi_lib.c:304 read_capacity_16+0x2b4/0x1450 drivers/scsi/sd.c:2655 sd_read_capacity drivers/scsi/sd.c:2824 [inline] sd_revalidate_disk+0x1013/0xbce0 drivers/scsi/sd.c:3734 sd_probe+0x9fa/0x1100 drivers/scsi/sd.c:4010 really_probe+0x2b8/0xad0 drivers/base/dd.c:658 __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800 driver_probe_device+0x50/0x430 drivers/base/dd.c:830 __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:459 __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987 async_run_entry_fn+0xa8/0x420 kernel/async.c:129 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (&q->limits_lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 queue_limits_start_update include/linux/blkdev.h:949 [inline] loop_reconfigure_limits+0x43f/0x900 drivers/block/loop.c:998 loop_set_block_size drivers/block/loop.c:1473 [inline] lo_simple_ioctl drivers/block/loop.c:1496 [inline] lo_ioctl+0x1351/0x1f50 drivers/block/loop.c:1559 blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &q->limits_lock --> &xfs_nondir_ilock_class --> &q->q_usage_counter(io)#17 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->q_usage_counter(io)#17); lock(&xfs_nondir_ilock_class); lock(&q->q_usage_counter(io)#17); lock(&q->limits_lock); *** DEADLOCK *** 3 locks held by syz.0.0/5316: #0: ffff8880004cb360 (&lo->lo_mutex){+.+.}-{4:4}, at: lo_simple_ioctl drivers/block/loop.c:1485 [inline] #0: ffff8880004cb360 (&lo->lo_mutex){+.+.}-{4:4}, at: lo_ioctl+0x606/0x1f50 drivers/block/loop.c:1559 #1: ffff8880346b1e00 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: loop_set_block_size drivers/block/loop.c:1472 [inline] #1: ffff8880346b1e00 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: lo_simple_ioctl drivers/block/loop.c:1496 [inline] #1: ffff8880346b1e00 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: lo_ioctl+0x1344/0x1f50 drivers/block/loop.c:1559 #2: ffff8880346b1e38 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: loop_set_block_size drivers/block/loop.c:1472 [inline] #2: ffff8880346b1e38 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: lo_simple_ioctl drivers/block/loop.c:1496 [inline] #2: ffff8880346b1e38 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: lo_ioctl+0x1344/0x1f50 drivers/block/loop.c:1559 stack backtrace: CPU: 0 UID: 0 PID: 5316 Comm: syz.0.0 Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 queue_limits_start_update include/linux/blkdev.h:949 [inline] loop_reconfigure_limits+0x43f/0x900 drivers/block/loop.c:998 loop_set_block_size drivers/block/loop.c:1473 [inline] lo_simple_ioctl drivers/block/loop.c:1496 [inline] lo_ioctl+0x1351/0x1f50 drivers/block/loop.c:1559 blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb0f537ff19 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:00007fb0f6103058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb0f5546080 RCX: 00007fb0f537ff19 RDX: 0000000000000800 RSI: 0000000000004c09 RDI: 0000000000000009 RBP: 00007fb0f53f3cc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb0f5546080 R15: 00007ffc42668818