netlink: 4 bytes leftover after parsing attributes in process `syz.9.916'. netlink: 32 bytes leftover after parsing attributes in process `syz.9.916'. ====================================================== WARNING: possible circular locking dependency detected 6.12.0-next-20241120-syzkaller #0 Not tainted ------------------------------------------------------ syz.9.916/10921 is trying to acquire lock: ffff888143f9df00 (&q->limits_lock){+.+.}-{4:4}, at: queue_limits_start_update include/linux/blkdev.h:949 [inline] ffff888143f9df00 (&q->limits_lock){+.+.}-{4:4}, at: __nbd_set_size drivers/block/nbd.c:351 [inline] ffff888143f9df00 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x2e0/0x8f0 drivers/block/nbd.c:388 but task is already holding lock: ffff888143f9d8b0 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_set_size+0xe0/0x8f0 drivers/block/nbd.c:387 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&q->q_usage_counter(io)#49){++++}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1536/0x23a0 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 submit_bh fs/buffer.c:2819 [inline] block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2446 filemap_read_folio+0x14b/0x630 mm/filemap.c:2366 filemap_update_page mm/filemap.c:2450 [inline] filemap_get_pages+0x17af/0x2540 mm/filemap.c:2571 filemap_read+0x45c/0xf50 mm/filemap.c:2646 blkdev_read_iter+0x2d8/0x430 block/fops.c:767 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x991/0xb70 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 -> #4 (mapping.invalidate_lock#2){++++}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:873 [inline] filemap_fault+0xd54/0x1950 mm/filemap.c:3351 __do_fault+0x135/0x460 mm/memory.c:4907 do_read_fault mm/memory.c:5322 [inline] do_fault mm/memory.c:5456 [inline] do_pte_missing mm/memory.c:3979 [inline] handle_pte_fault+0x3c01/0x66b0 mm/memory.c:5801 __handle_mm_fault mm/memory.c:5944 [inline] handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6112 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 iovec_from_user+0xfb/0x240 lib/iov_iter.c:1411 process_vm_rw+0x2d9/0xc50 mm/process_vm_access.c:278 __do_sys_process_vm_readv mm/process_vm_access.c:296 [inline] __se_sys_process_vm_readv mm/process_vm_access.c:292 [inline] __x64_sys_process_vm_readv+0xe0/0x100 mm/process_vm_access.c:292 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 (&mm->mmap_lock){++++}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __might_fault+0xc6/0x120 mm/memory.c:6751 _inline_copy_from_user include/linux/uaccess.h:162 [inline] _copy_from_user+0x2a/0xc0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] __blk_trace_setup kernel/trace/blktrace.c:626 [inline] blk_trace_setup+0xd2/0x1e0 kernel/trace/blktrace.c:648 sg_ioctl_common drivers/scsi/sg.c:1114 [inline] sg_ioctl+0xa46/0x2e80 drivers/scsi/sg.c:1156 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 -> #2 (&q->debugfs_mutex){+.+.}-{4:4}: 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 blk_mq_init_sched+0x3fa/0x830 block/blk-mq-sched.c:473 elevator_init_mq+0x20e/0x320 block/elevator.c:610 add_disk_fwnode+0x10d/0xf80 block/genhd.c:413 sd_probe+0xba6/0x1100 drivers/scsi/sd.c:4024 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+0xa63/0x1850 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)#50){++++}-{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+0xa63/0x1850 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] __nbd_set_size drivers/block/nbd.c:351 [inline] nbd_set_size+0x2e0/0x8f0 drivers/block/nbd.c:388 nbd_genl_connect+0x157c/0x1c80 drivers/block/nbd.c:2139 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2541 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:726 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583 ___sys_sendmsg net/socket.c:2637 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2669 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 --> mapping.invalidate_lock#2 --> &q->q_usage_counter(io)#49 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->q_usage_counter(io)#49); lock(mapping.invalidate_lock#2); lock(&q->q_usage_counter(io)#49); lock(&q->limits_lock); *** DEADLOCK *** 5 locks held by syz.9.916/10921: #0: ffffffff8fd03410 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8fd032c8 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fd032c8 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fd032c8 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x121/0xec0 net/netlink/genetlink.c:1209 #2: ffff888025453198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_connect+0xc26/0x1c80 drivers/block/nbd.c:2049 #3: ffff888143f9d8b0 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_set_size+0xe0/0x8f0 drivers/block/nbd.c:387 #4: ffff888143f9d8e8 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: nbd_set_size+0xe0/0x8f0 drivers/block/nbd.c:387 stack backtrace: CPU: 0 UID: 0 PID: 10921 Comm: syz.9.916 Not tainted 6.12.0-next-20241120-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 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] __nbd_set_size drivers/block/nbd.c:351 [inline] nbd_set_size+0x2e0/0x8f0 drivers/block/nbd.c:388 nbd_genl_connect+0x157c/0x1c80 drivers/block/nbd.c:2139 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2541 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:726 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583 ___sys_sendmsg net/socket.c:2637 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2669 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: 0033:0x7f9debb7e819 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:00007f9deca4e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f9debd35fa0 RCX: 00007f9debb7e819 RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 000000000000000a RBP: 00007f9debbf175e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f9debd35fa0 R15: 00007ffd6b95cd78