netlink: 32 bytes leftover after parsing attributes in process `syz.3.2020'. ====================================================== WARNING: possible circular locking dependency detected 6.12.0-syzkaller-07834-g06afb0f36106 #0 Not tainted ------------------------------------------------------ syz.3.2020/13202 is trying to acquire lock: ffff888107921a88 (&q->limits_lock){+.+.}-{4:4}, at: queue_limits_start_update include/linux/blkdev.h:945 [inline] ffff888107921a88 (&q->limits_lock){+.+.}-{4:4}, at: __nbd_set_size+0x2c0/0x730 drivers/block/nbd.c:351 but task is already holding lock: ffff888107921438 ( &q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_set_size drivers/block/nbd.c:387 [inline] &q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_start_device+0x8ef/0xd70 drivers/block/nbd.c:1456 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}: bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1fb6/0x24c0 block/blk-mq.c:3092 __submit_bio+0x384/0x540 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739 submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868 mpage_bio_submit_read fs/mpage.c:75 [inline] mpage_readahead+0x41d/0x590 fs/mpage.c:377 read_pages+0x1a8/0xdc0 mm/readahead.c:160 page_cache_ra_unbounded+0x3c0/0x6c0 mm/readahead.c:290 do_page_cache_ra mm/readahead.c:320 [inline] force_page_cache_ra+0x24b/0x340 mm/readahead.c:349 page_cache_sync_ra+0x110/0x9c0 mm/readahead.c:562 page_cache_sync_readahead include/linux/pagemap.h:1394 [inline] filemap_get_pages+0xd7b/0x1be0 mm/filemap.c:2547 filemap_read+0x3ca/0xd70 mm/filemap.c:2647 blkdev_read_iter+0x187/0x480 block/fops.c:767 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x87f/0xbe0 fs/read_write.c:565 ksys_read+0x12b/0x250 fs/read_write.c:708 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (mapping.invalidate_lock#2){++++}-{4:4}: down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:873 [inline] page_cache_ra_unbounded+0x173/0x6c0 mm/readahead.c:226 do_page_cache_ra mm/readahead.c:320 [inline] page_cache_ra_order+0x7d9/0xc90 mm/readahead.c:520 page_cache_async_ra+0x5cb/0x820 mm/readahead.c:670 do_async_mmap_readahead mm/filemap.c:3232 [inline] filemap_fault+0xd69/0x2820 mm/filemap.c:3331 __do_fault+0x10a/0x490 mm/memory.c:4882 do_read_fault mm/memory.c:5297 [inline] do_fault mm/memory.c:5431 [inline] do_pte_missing+0xec5/0x3e70 mm/memory.c:3965 handle_pte_fault mm/memory.c:5766 [inline] __handle_mm_fault+0x100a/0x2a10 mm/memory.c:5909 handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6077 faultin_page mm/gup.c:1187 [inline] __get_user_pages+0x8d9/0x3b50 mm/gup.c:1485 __get_user_pages_locked mm/gup.c:1751 [inline] get_dump_page+0xff/0x230 mm/gup.c:2269 dump_user_range+0x135/0x8c0 fs/coredump.c:943 elf_core_dump+0x27fd/0x39d0 fs/binfmt_elf.c:2127 do_coredump+0x2f50/0x42f0 fs/coredump.c:758 get_signal+0x230b/0x26c0 kernel/signal.c:3001 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&mm->mmap_lock){++++}-{4:4}: __might_fault mm/memory.c:6716 [inline] __might_fault+0x11b/0x190 mm/memory.c:6709 _inline_copy_from_user include/linux/uaccess.h:162 [inline] _copy_from_user+0x29/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] __blk_trace_setup+0xa8/0x180 kernel/trace/blktrace.c:626 blk_trace_setup+0x47/0x70 kernel/trace/blktrace.c:648 sg_ioctl_common drivers/scsi/sg.c:1121 [inline] sg_ioctl+0x65e/0x2750 drivers/scsi/sg.c:1163 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&q->debugfs_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 blk_mq_init_sched+0x42b/0x640 block/blk-mq-sched.c:473 elevator_init_mq+0x2cd/0x420 block/elevator.c:610 add_disk_fwnode+0x113/0x1300 block/genhd.c:413 sd_probe+0xa86/0x1000 drivers/scsi/sd.c:4024 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830 __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958 bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:459 __device_attach_async_helper+0x1d3/0x290 drivers/base/dd.c:987 async_run_entry_fn+0x9c/0x530 kernel/async.c:129 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 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)#51){++++}-{0:0}: blk_queue_enter+0x50f/0x640 block/blk-core.c:328 blk_mq_alloc_request+0x59b/0x950 block/blk-mq.c:652 scsi_alloc_request drivers/scsi/scsi_lib.c:1222 [inline] scsi_execute_cmd+0x1eb/0xf40 drivers/scsi/scsi_lib.c:304 read_capacity_16+0x213/0xe10 drivers/scsi/sd.c:2655 sd_read_capacity drivers/scsi/sd.c:2824 [inline] sd_revalidate_disk.isra.0+0x1a06/0xa8d0 drivers/scsi/sd.c:3734 sd_probe+0x904/0x1000 drivers/scsi/sd.c:4010 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830 __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958 bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:459 __device_attach_async_helper+0x1d3/0x290 drivers/base/dd.c:987 async_run_entry_fn+0x9c/0x530 kernel/async.c:129 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 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 kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 queue_limits_start_update include/linux/blkdev.h:945 [inline] __nbd_set_size+0x2c0/0x730 drivers/block/nbd.c:351 nbd_set_size drivers/block/nbd.c:388 [inline] nbd_start_device+0x8fd/0xd70 drivers/block/nbd.c:1456 nbd_genl_connect+0x1204/0x1c00 drivers/block/nbd.c:2139 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x16b/0x440 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+0x53c/0x7f0 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726 [inline] ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2583 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637 __sys_sendmsg+0x16e/0x220 net/socket.c:2669 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 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.3.2020/13202: #0: ffffffff8ff7ae10 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8ff7aec8 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8ff7aec8 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8ff7aec8 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:57 [inline] #1: ffffffff8ff7aec8 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x580/0x800 net/netlink/genetlink.c:1209 #2: ffff888025e05198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_connect+0xa1b/0x1c00 drivers/block/nbd.c:2049 #3: ffff888107921438 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_set_size drivers/block/nbd.c:387 [inline] #3: ffff888107921438 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_start_device+0x8ef/0xd70 drivers/block/nbd.c:1456 #4: ffff888107921470 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: nbd_set_size drivers/block/nbd.c:387 [inline] #4: ffff888107921470 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: nbd_start_device+0x8ef/0xd70 drivers/block/nbd.c:1456 stack backtrace: CPU: 2 UID: 0 PID: 13202 Comm: syz.3.2020 Not tainted 6.12.0-syzkaller-07834-g06afb0f36106 #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+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 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 kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 queue_limits_start_update include/linux/blkdev.h:945 [inline] __nbd_set_size+0x2c0/0x730 drivers/block/nbd.c:351 nbd_set_size drivers/block/nbd.c:388 [inline] nbd_start_device+0x8fd/0xd70 drivers/block/nbd.c:1456 nbd_genl_connect+0x1204/0x1c00 drivers/block/nbd.c:2139 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x16b/0x440 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+0x53c/0x7f0 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726 [inline] ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2583 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637 __sys_sendmsg+0x16e/0x220 net/socket.c:2669 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3c1f17e819 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:00007f3c1cff6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f3c1f335fa0 RCX: 00007f3c1f17e819 RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 000000000000000a RBP: 00007f3c1f1f175e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3c1f335fa0 R15: 00007ffc4f5e2608 nbd0: detected capacity change from 0 to 256