====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.2034/12276 is trying to acquire lock: ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:318 [inline] ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4898 [inline] ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:5222 [inline] ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: __do_kmalloc_node mm/slub.c:5603 [inline] ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_noprof+0x9c/0x7f0 mm/slub.c:5616 but task is already holding lock: ffffffff8f5e3b08 (cpool_mutex){+.+.}-{4:4}, at: tcp_sigpool_alloc_ahash+0x88/0xc70 net/ipv4/tcp_sigpool.c:162 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (cpool_mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 tcp_sigpool_alloc_ahash+0x88/0xc70 net/ipv4/tcp_sigpool.c:162 tcp_md5_alloc_sigpool+0x1b/0x50 net/ipv4/tcp.c:4824 tcp_md5_do_add+0x107/0x3a0 net/ipv4/tcp_ipv4.c:1428 tcp_v4_parse_md5_keys+0x412/0x600 net/ipv4/tcp_ipv4.c:1577 do_tcp_setsockopt+0x11dc/0x1f20 net/ipv4/tcp.c:4059 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2360 __sys_setsockopt net/socket.c:2385 [inline] __do_sys_setsockopt net/socket.c:2391 [inline] __se_sys_setsockopt net/socket.c:2388 [inline] __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2388 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #6 (sk_lock-AF_INET){+.+.}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 lock_sock_nested+0x48/0x100 net/core/sock.c:3720 lock_sock include/net/sock.h:1679 [inline] inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:907 nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318 recv_work+0x2138/0x24f0 drivers/block/nbd.c:1018 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #5 (&nsock->tx_lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 nbd_handle_cmd drivers/block/nbd.c:1140 [inline] nbd_queue_rq+0x257/0xf10 drivers/block/nbd.c:1204 blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xda4/0x1570 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367 blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976 __blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1225 blk_finish_plug block/blk-core.c:1252 [inline] __submit_bio+0x2d3/0x5a0 block/blk-core.c:651 __submit_bio_noacct_mq block/blk-core.c:724 [inline] submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:755 submit_bh fs/buffer.c:2829 [inline] block_read_full_folio+0x7b7/0x830 fs/buffer.c:2461 filemap_read_folio+0x117/0x380 mm/filemap.c:2444 do_read_cache_folio+0x350/0x590 mm/filemap.c:4024 read_mapping_folio include/linux/pagemap.h:999 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:722 adfspart_check_ICS+0xa4/0xa50 block/partitions/acorn.c:360 check_partition block/partitions/core.c:141 [inline] blk_add_partitions block/partitions/core.c:589 [inline] bdev_disk_changed+0x75f/0x14b0 block/partitions/core.c:693 blkdev_get_whole+0x380/0x510 block/bdev.c:748 bdev_open+0x31e/0xd30 block/bdev.c:957 blkdev_open+0x457/0x600 block/fops.c:694 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (&cmd->lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 nbd_queue_rq+0xc8/0xf10 drivers/block/nbd.c:1196 blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xda4/0x1570 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367 blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976 __blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1225 blk_finish_plug block/blk-core.c:1252 [inline] __submit_bio+0x2d3/0x5a0 block/blk-core.c:651 __submit_bio_noacct_mq block/blk-core.c:724 [inline] submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:755 submit_bh fs/buffer.c:2829 [inline] block_read_full_folio+0x7b7/0x830 fs/buffer.c:2461 filemap_read_folio+0x117/0x380 mm/filemap.c:2444 do_read_cache_folio+0x350/0x590 mm/filemap.c:4024 read_mapping_folio include/linux/pagemap.h:999 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:722 adfspart_check_ICS+0xa4/0xa50 block/partitions/acorn.c:360 check_partition block/partitions/core.c:141 [inline] blk_add_partitions block/partitions/core.c:589 [inline] bdev_disk_changed+0x75f/0x14b0 block/partitions/core.c:693 blkdev_get_whole+0x380/0x510 block/bdev.c:748 bdev_open+0x31e/0xd30 block/bdev.c:957 blkdev_open+0x457/0x600 block/fops.c:694 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (set->srcu){.+.+}-{0:0}: lock_sync+0xba/0x160 kernel/locking/lockdep.c:5916 srcu_lock_sync include/linux/srcu.h:173 [inline] __synchronize_srcu+0x96/0x3a0 kernel/rcu/srcutree.c:1439 elevator_switch+0x12b/0x640 block/elevator.c:588 elevator_change+0x315/0x4c0 block/elevator.c:691 elevator_set_default+0x186/0x260 block/elevator.c:767 blk_register_queue+0x34e/0x3f0 block/blk-sysfs.c:942 __add_disk+0x677/0xd50 block/genhd.c:528 add_disk_fwnode+0xfc/0x480 block/genhd.c:597 add_disk include/linux/blkdev.h:775 [inline] nbd_dev_add+0x717/0xae0 drivers/block/nbd.c:1981 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2688 do_one_initcall+0x236/0x820 init/main.c:1283 do_initcall_level+0x104/0x190 init/main.c:1345 do_initcalls+0x59/0xa0 init/main.c:1361 kernel_init_freeable+0x334/0x4b0 init/main.c:1593 kernel_init+0x1d/0x1d0 init/main.c:1483 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (&q->elevator_lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 elevator_change+0x1e5/0x4c0 block/elevator.c:689 elevator_set_none+0x42/0xb0 block/elevator.c:782 blk_mq_elv_switch_none block/blk-mq.c:5032 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5075 [inline] blk_mq_update_nr_hw_queues+0x598/0x1ab0 block/blk-mq.c:5133 nbd_start_device+0x17f/0xb10 drivers/block/nbd.c:1486 nbd_genl_connect+0x135b/0x18f0 drivers/block/nbd.c:2236 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 blk_alloc_queue+0x538/0x620 block/blk-core.c:461 blk_mq_alloc_queue block/blk-mq.c:4399 [inline] __blk_mq_alloc_disk+0x15c/0x340 block/blk-mq.c:4446 nbd_dev_add+0x46c/0xae0 drivers/block/nbd.c:1951 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2688 do_one_initcall+0x236/0x820 init/main.c:1283 do_initcall_level+0x104/0x190 init/main.c:1345 do_initcalls+0x59/0xa0 init/main.c:1361 kernel_init_freeable+0x334/0x4b0 init/main.c:1593 kernel_init+0x1d/0x1d0 init/main.c:1483 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4269 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4283 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4898 [inline] slab_alloc_node mm/slub.c:5222 [inline] __do_kmalloc_node mm/slub.c:5603 [inline] __kmalloc_noprof+0x9c/0x7f0 mm/slub.c:5616 kmalloc_noprof include/linux/slab.h:961 [inline] sigpool_reserve_scratch net/ipv4/tcp_sigpool.c:66 [inline] tcp_sigpool_alloc_ahash+0x144/0xc70 net/ipv4/tcp_sigpool.c:163 tcp_md5_alloc_sigpool+0x1b/0x50 net/ipv4/tcp.c:4824 tcp_md5_do_add+0x107/0x3a0 net/ipv4/tcp_ipv4.c:1428 tcp_v6_parse_md5_keys+0x4df/0x610 net/ipv6/tcp_ipv6.c:-1 do_tcp_setsockopt+0x11dc/0x1f20 net/ipv4/tcp.c:4059 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2360 __sys_setsockopt net/socket.c:2385 [inline] __do_sys_setsockopt net/socket.c:2391 [inline] __se_sys_setsockopt net/socket.c:2388 [inline] __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2388 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: fs_reclaim --> sk_lock-AF_INET --> cpool_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(cpool_mutex); lock(sk_lock-AF_INET); lock(cpool_mutex); lock(fs_reclaim); *** DEADLOCK *** 2 locks held by syz.3.2034/12276: #0: ffff888033c00fd8 (sk_lock-AF_INET6){+.+.}-{0:0}, at: do_tcp_setsockopt+0x854/0x1f20 net/ipv4/tcp.c:3928 #1: ffffffff8f5e3b08 (cpool_mutex){+.+.}-{4:4}, at: tcp_sigpool_alloc_ahash+0x88/0xc70 net/ipv4/tcp_sigpool.c:162 stack backtrace: CPU: 1 UID: 0 PID: 12276 Comm: syz.3.2034 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4269 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4283 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4898 [inline] slab_alloc_node mm/slub.c:5222 [inline] __do_kmalloc_node mm/slub.c:5603 [inline] __kmalloc_noprof+0x9c/0x7f0 mm/slub.c:5616 kmalloc_noprof include/linux/slab.h:961 [inline] sigpool_reserve_scratch net/ipv4/tcp_sigpool.c:66 [inline] tcp_sigpool_alloc_ahash+0x144/0xc70 net/ipv4/tcp_sigpool.c:163 tcp_md5_alloc_sigpool+0x1b/0x50 net/ipv4/tcp.c:4824 tcp_md5_do_add+0x107/0x3a0 net/ipv4/tcp_ipv4.c:1428 tcp_v6_parse_md5_keys+0x4df/0x610 net/ipv6/tcp_ipv6.c:-1 do_tcp_setsockopt+0x11dc/0x1f20 net/ipv4/tcp.c:4059 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2360 __sys_setsockopt net/socket.c:2385 [inline] __do_sys_setsockopt net/socket.c:2391 [inline] __se_sys_setsockopt net/socket.c:2388 [inline] __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2388 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f685bf8eec9 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:00007f685cf11038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f685c1e5fa0 RCX: 00007f685bf8eec9 RDX: 000000000000000e RSI: 0000000000000006 RDI: 0000000000000003 RBP: 00007f685c011f91 R08: 00000000000000d8 R09: 0000000000000000 R10: 0000200000000300 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f685c1e6038 R14: 00007f685c1e5fa0 R15: 00007ffc52929448