====================================================== WARNING: possible circular locking dependency detected 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Not tainted ------------------------------------------------------ syz.5.115/6402 is trying to acquire lock: ffff888021716490 (set->srcu){.+.+}-{0:0}, at: srcu_lock_sync include/linux/srcu.h:176 [inline] ffff888021716490 (set->srcu){.+.+}-{0:0}, at: __synchronize_srcu+0x9d/0x400 kernel/rcu/srcutree.c:1418 but task is already holding lock: ffff8881443e8f08 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_elv_switch_none block/blk-mq.c:4937 [inline] ffff8881443e8f08 (&q->sysfs_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline] ffff8881443e8f08 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x388/0x1a30 block/blk-mq.c:5070 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&q->sysfs_lock){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 blk_mq_elv_switch_none block/blk-mq.c:4937 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline] blk_mq_update_nr_hw_queues+0x388/0x1a30 block/blk-mq.c:5070 nbd_start_device+0x163/0xab0 drivers/block/nbd.c:1476 nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline] __nbd_ioctl drivers/block/nbd.c:1602 [inline] nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1642 blkdev_ioctl+0x5d2/0x6f0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf7/0x170 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 -> #6 (&q->q_usage_counter(io)#54){++++}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 bio_queue_enter block/blk.h:77 [inline] blk_mq_submit_bio+0x14e1/0x25a0 block/blk-mq.c:3091 __submit_bio+0x2cf/0x6a0 block/blk-core.c:628 __submit_bio_noacct_mq block/blk-core.c:715 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744 mpage_bio_submit_read fs/mpage.c:75 [inline] mpage_readahead+0x630/0x780 fs/mpage.c:377 read_pages+0x17b/0x570 mm/readahead.c:161 page_cache_ra_unbounded+0x708/0x820 mm/readahead.c:298 do_page_cache_ra mm/readahead.c:328 [inline] force_page_cache_ra mm/readahead.c:357 [inline] page_cache_sync_ra+0x3e2/0xb00 mm/readahead.c:585 filemap_get_pages+0x59a/0x1fb0 mm/filemap.c:2580 filemap_read+0x464/0x1260 mm/filemap.c:2691 blkdev_read_iter+0x31f/0x460 block/fops.c:796 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x977/0xb40 fs/read_write.c:565 ksys_read+0x18f/0x2b0 fs/read_write.c:708 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 -> #5 (mapping.invalidate_lock#2){.+.+}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:932 [inline] page_cache_ra_unbounded+0x156/0x820 mm/readahead.c:229 do_sync_mmap_readahead+0x4a6/0x990 filemap_fault+0x89e/0x16c0 mm/filemap.c:3447 __do_fault+0x137/0x390 mm/memory.c:4988 do_read_fault mm/memory.c:5403 [inline] do_fault mm/memory.c:5537 [inline] do_pte_missing mm/memory.c:4058 [inline] handle_pte_fault mm/memory.c:5900 [inline] __handle_mm_fault+0x4c44/0x70f0 mm/memory.c:6043 handle_mm_fault+0x3e5/0x8d0 mm/memory.c:6212 do_user_addr_fault arch/x86/mm/fault.c:1388 [inline] handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x2b9/0x8b0 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] _inline_copy_from_user include/linux/uaccess.h:178 [inline] _copy_from_user+0x76/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] copy_msghdr_from_user+0xae/0x680 net/socket.c:2503 recvmsg_copy_msghdr net/socket.c:2759 [inline] ___sys_recvmsg net/socket.c:2831 [inline] do_recvmmsg+0x3bd/0xab0 net/socket.c:2930 __sys_recvmmsg net/socket.c:3004 [inline] __do_sys_recvmmsg net/socket.c:3027 [inline] __se_sys_recvmmsg net/socket.c:3020 [inline] __x64_sys_recvmmsg+0x199/0x250 net/socket.c:3020 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 -> #4 (&mm->mmap_lock){++++}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __might_fault+0xc6/0x120 mm/memory.c:6851 _copy_from_iter+0x100/0x1c40 lib/iov_iter.c:259 copy_from_iter include/linux/uio.h:228 [inline] copy_from_iter_full include/linux/uio.h:245 [inline] skb_do_copy_data_nocache include/net/sock.h:2196 [inline] skb_copy_to_page_nocache include/net/sock.h:2222 [inline] tcp_sendmsg_locked+0x213d/0x5330 net/ipv4/tcp.c:1222 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1358 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:733 sock_write_iter+0x2d7/0x3f0 net/socket.c:1137 new_sync_write fs/read_write.c:586 [inline] vfs_write+0xad1/0xd10 fs/read_write.c:679 ksys_write+0x18f/0x2b0 fs/read_write.c:731 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 -> #3 (sk_lock-AF_INET){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 lock_sock_nested+0x48/0x100 net/core/sock.c:3645 lock_sock include/net/sock.h:1624 [inline] inet_autobind net/ipv4/af_inet.c:178 [inline] inet_send_prepare net/ipv4/af_inet.c:837 [inline] inet_sendmsg+0x120/0x390 net/ipv4/af_inet.c:848 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:733 sock_sendmsg+0x16c/0x250 net/socket.c:756 __sock_xmit+0x219/0x4e0 drivers/block/nbd.c:574 sock_xmit drivers/block/nbd.c:602 [inline] nbd_send_cmd+0x996/0x2110 drivers/block/nbd.c:712 nbd_handle_cmd drivers/block/nbd.c:1174 [inline] nbd_queue_rq+0xcd5/0xef0 drivers/block/nbd.c:1204 blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline] __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309 blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331 blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354 blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2917 __blk_flush_plug+0x420/0x500 block/blk-core.c:1213 blk_finish_plug block/blk-core.c:1240 [inline] __submit_bio+0x54a/0x6a0 block/blk-core.c:642 __submit_bio_noacct_mq block/blk-core.c:715 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744 submit_bh fs/buffer.c:2819 [inline] __bread_slow fs/buffer.c:1264 [inline] __bread_gfp+0x23c/0x400 fs/buffer.c:1488 sb_bread include/linux/buffer_head.h:346 [inline] udf_read_tagged+0xa6/0xe00 fs/udf/misc.c:199 udf_check_anchor_block+0xba/0x550 fs/udf/super.c:1903 udf_scan_anchors fs/udf/super.c:1943 [inline] udf_load_vrs+0x767/0x1130 fs/udf/super.c:2024 udf_fill_super+0x5f2/0x1cb0 fs/udf/super.c:2192 get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636 vfs_get_tree+0x92/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 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 -> #2 (&nsock->tx_lock){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 nbd_handle_cmd drivers/block/nbd.c:1140 [inline] nbd_queue_rq+0x262/0xef0 drivers/block/nbd.c:1204 blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline] __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309 blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331 blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354 blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2917 __blk_flush_plug+0x420/0x500 block/blk-core.c:1213 blk_finish_plug block/blk-core.c:1240 [inline] __submit_bio+0x54a/0x6a0 block/blk-core.c:642 __submit_bio_noacct_mq block/blk-core.c:715 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744 submit_bh fs/buffer.c:2819 [inline] __bread_slow fs/buffer.c:1264 [inline] __bread_gfp+0x23c/0x400 fs/buffer.c:1488 sb_bread include/linux/buffer_head.h:346 [inline] udf_read_tagged+0xa6/0xe00 fs/udf/misc.c:199 udf_check_anchor_block+0xba/0x550 fs/udf/super.c:1903 udf_scan_anchors fs/udf/super.c:1943 [inline] udf_load_vrs+0x767/0x1130 fs/udf/super.c:2024 udf_fill_super+0x5f2/0x1cb0 fs/udf/super.c:2192 get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636 vfs_get_tree+0x92/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 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 -> #1 (&cmd->lock){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 nbd_queue_rq+0xcf/0xef0 drivers/block/nbd.c:1196 blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline] __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309 blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331 blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354 blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2917 __blk_flush_plug+0x420/0x500 block/blk-core.c:1213 blk_finish_plug block/blk-core.c:1240 [inline] __submit_bio+0x54a/0x6a0 block/blk-core.c:642 __submit_bio_noacct_mq block/blk-core.c:715 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744 submit_bh fs/buffer.c:2819 [inline] __bread_slow fs/buffer.c:1264 [inline] __bread_gfp+0x23c/0x400 fs/buffer.c:1488 sb_bread include/linux/buffer_head.h:346 [inline] udf_read_tagged+0xa6/0xe00 fs/udf/misc.c:199 udf_check_anchor_block+0xba/0x550 fs/udf/super.c:1903 udf_scan_anchors fs/udf/super.c:1943 [inline] udf_load_vrs+0x767/0x1130 fs/udf/super.c:2024 udf_fill_super+0x5f2/0x1cb0 fs/udf/super.c:2192 get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636 vfs_get_tree+0x92/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 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 -> #0 (set->srcu){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_sync+0x18b/0x310 kernel/locking/lockdep.c:5899 srcu_lock_sync include/linux/srcu.h:176 [inline] __synchronize_srcu+0xb1/0x400 kernel/rcu/srcutree.c:1418 elevator_disable+0xd4/0x4e0 block/elevator.c:661 blk_mq_elv_switch_none block/blk-mq.c:4951 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline] blk_mq_update_nr_hw_queues+0x5d3/0x1a30 block/blk-mq.c:5070 nbd_start_device+0x163/0xab0 drivers/block/nbd.c:1476 nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline] __nbd_ioctl drivers/block/nbd.c:1602 [inline] nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1642 blkdev_ioctl+0x5d2/0x6f0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf7/0x170 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: set->srcu --> &q->q_usage_counter(io)#54 --> &q->sysfs_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_lock); lock(&q->q_usage_counter(io)#54); lock(&q->sysfs_lock); sync(set->srcu); *** DEADLOCK *** 5 locks held by syz.5.115/6402: #0: ffff8881443f8998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1635 #1: ffff8881443f88d8 (&set->tag_list_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0xa0/0x1a30 block/blk-mq.c:5069 #2: ffff8881443e89d8 (&q->q_usage_counter(io)#54){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5010 [inline] #2: ffff8881443e89d8 (&q->q_usage_counter(io)#54){++++}-{0:0}, at: blk_mq_update_nr_hw_queues+0x2c3/0x1a30 block/blk-mq.c:5070 #3: ffff8881443e8a10 (&q->q_usage_counter(queue)#38){+.+.}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5010 [inline] #3: ffff8881443e8a10 (&q->q_usage_counter(queue)#38){+.+.}-{0:0}, at: blk_mq_update_nr_hw_queues+0x2c3/0x1a30 block/blk-mq.c:5070 #4: ffff8881443e8f08 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_elv_switch_none block/blk-mq.c:4937 [inline] #4: ffff8881443e8f08 (&q->sysfs_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline] #4: ffff8881443e8f08 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x388/0x1a30 block/blk-mq.c:5070 stack backtrace: CPU: 0 UID: 0 PID: 6402 Comm: syz.5.115 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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:2076 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208 check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_sync+0x18b/0x310 kernel/locking/lockdep.c:5899 srcu_lock_sync include/linux/srcu.h:176 [inline] __synchronize_srcu+0xb1/0x400 kernel/rcu/srcutree.c:1418 elevator_disable+0xd4/0x4e0 block/elevator.c:661 blk_mq_elv_switch_none block/blk-mq.c:4951 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline] blk_mq_update_nr_hw_queues+0x5d3/0x1a30 block/blk-mq.c:5070 nbd_start_device+0x163/0xab0 drivers/block/nbd.c:1476 nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline] __nbd_ioctl drivers/block/nbd.c:1602 [inline] nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1642 blkdev_ioctl+0x5d2/0x6f0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf7/0x170 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: 0033:0x7fca4658d169 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:00007fca47338038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fca467a5fa0 RCX: 00007fca4658d169 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 00007fca4660e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fca467a5fa0 R15: 00007ffdbde849c8 block nbd5: shutting down sockets