syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.2126/13673 is trying to acquire lock:
ffff888034ffb438 (&mm->mmap_lock){++++}-{4:4}, at: gup_fast_fallback+0x20d/0x20d0 mm/gup.c:3193

but task is already holding lock:
ffff8880359d8fe0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
ffff8880359d8fe0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: tls_sw_sendmsg+0x15e/0x2400 net/tls/tls_sw.c:1301

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100 net/core/sock.c:3792
       lock_sock include/net/sock.h:1713 [inline]
       inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:915
       nbd_mark_nsock_dead+0x2cb/0x550 drivers/block/nbd.c:318
       recv_work+0x1cef/0x1e10 drivers/block/nbd.c:1021
       process_one_work kernel/workqueue.c:3314 [inline]
       process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478
       kthread+0x389/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1590 kernel/locking/mutex.c:820
       nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
       nbd_queue_rq+0x373/0x1150 drivers/block/nbd.c:1207
       blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2148
       __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+0xd36/0x1580 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:2387
       blk_mq_dispatch_list+0xd11/0xe10 include/linux/spinlock.h:-1
       blk_mq_flush_plug_list+0x45f/0x540 block/blk-mq.c:2997
       __blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
       blk_finish_plug block/blk-core.c:1257 [inline]
       __submit_bio+0x465/0x560 block/blk-core.c:649
       __submit_bio_noacct_mq block/blk-core.c:722 [inline]
       submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753
       submit_bh fs/buffer.c:2742 [inline]
       block_read_full_folio+0x599/0x830 fs/buffer.c:2344
       filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2502
       do_read_cache_folio+0x354/0x590 mm/filemap.c:4107
       read_mapping_folio include/linux/pagemap.h:1017 [inline]
       read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
       adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:356
       check_partition block/partitions/core.c:143 [inline]
       blk_add_partitions block/partitions/core.c:591 [inline]
       bdev_disk_changed+0x82b/0x1780 block/partitions/core.c:695
       blkdev_get_whole+0x372/0x510 block/bdev.c:756
       bdev_open+0x324/0xd70 block/bdev.c:965
       blkdev_open+0x461/0x600 block/fops.c:697
       do_dentry_open+0x816/0x1380 fs/open.c:947
       vfs_open+0x3b/0x340 fs/open.c:1079
       do_open fs/namei.c:4699 [inline]
       path_openat+0x2e3b/0x3890 fs/namei.c:4858
       do_file_open+0x23e/0x4a0 fs/namei.c:4887
       do_sys_openat2+0x113/0x200 fs/open.c:1364
       do_sys_open fs/open.c:1370 [inline]
       __do_sys_openat fs/open.c:1386 [inline]
       __se_sys_openat fs/open.c:1381 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1381
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1590 kernel/locking/mutex.c:820
       nbd_queue_rq+0xc1/0x1150 drivers/block/nbd.c:1199
       blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2148
       __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+0xd36/0x1580 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:2387
       blk_mq_dispatch_list+0xd11/0xe10 include/linux/spinlock.h:-1
       blk_mq_flush_plug_list+0x45f/0x540 block/blk-mq.c:2997
       __blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
       blk_finish_plug block/blk-core.c:1257 [inline]
       __submit_bio+0x465/0x560 block/blk-core.c:649
       __submit_bio_noacct_mq block/blk-core.c:722 [inline]
       submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753
       submit_bh fs/buffer.c:2742 [inline]
       block_read_full_folio+0x599/0x830 fs/buffer.c:2344
       filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2502
       do_read_cache_folio+0x354/0x590 mm/filemap.c:4107
       read_mapping_folio include/linux/pagemap.h:1017 [inline]
       read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
       adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:356
       check_partition block/partitions/core.c:143 [inline]
       blk_add_partitions block/partitions/core.c:591 [inline]
       bdev_disk_changed+0x82b/0x1780 block/partitions/core.c:695
       blkdev_get_whole+0x372/0x510 block/bdev.c:756
       bdev_open+0x324/0xd70 block/bdev.c:965
       blkdev_open+0x461/0x600 block/fops.c:697
       do_dentry_open+0x816/0x1380 fs/open.c:947
       vfs_open+0x3b/0x340 fs/open.c:1079
       do_open fs/namei.c:4699 [inline]
       path_openat+0x2e3b/0x3890 fs/namei.c:4858
       do_file_open+0x23e/0x4a0 fs/namei.c:4887
       do_sys_openat2+0x113/0x200 fs/open.c:1364
       do_sys_open fs/open.c:1370 [inline]
       __do_sys_openat fs/open.c:1386 [inline]
       __se_sys_openat fs/open.c:1381 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1381
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (set->srcu){.+.+}-{0:0}:
       srcu_lock_sync include/linux/srcu.h:199 [inline]
       __synchronize_srcu+0xc9/0x2f0 kernel/rcu/srcutree.c:1481
       elevator_switch+0x1e8/0x7b0 block/elevator.c:576
       elevator_change+0x2fa/0x480 block/elevator.c:681
       elevator_set_default+0x375/0x440 block/elevator.c:754
       blk_register_queue+0x3f3/0x4e0 block/blk-sysfs.c:987
       __add_disk+0x6cb/0xe30 block/genhd.c:528
       add_disk_fwnode+0xfb/0x4b0 block/genhd.c:597
       add_disk include/linux/blkdev.h:794 [inline]
       nbd_dev_add+0x733/0xb60 drivers/block/nbd.c:1984
       nbd_init+0x15f/0x1e0 drivers/block/nbd.c:2692
       do_one_initcall+0x250/0x870 init/main.c:1392
       do_initcall_level+0x10a/0x1a0 init/main.c:1454
       do_initcalls+0x59/0xa0 init/main.c:1470
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1703
       kernel_init+0x1d/0x1d0 init/main.c:1593
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1590 kernel/locking/mutex.c:820
       elevator_change+0x1af/0x480 block/elevator.c:679
       elevator_set_none+0xb5/0x140 block/elevator.c:769
       blk_mq_elv_switch_none block/blk-mq.c:5134 [inline]
       __blk_mq_update_nr_hw_queues block/blk-mq.c:5179 [inline]
       blk_mq_update_nr_hw_queues+0x5ef/0x19f0 block/blk-mq.c:5244
       nbd_start_device+0x189/0xb30 drivers/block/nbd.c:1489
       nbd_genl_connect+0x1597/0x1c10 drivers/block/nbd.c:2239
       genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
       genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
       genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
       netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2555
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1899
       sock_sendmsg_nosec net/socket.c:787 [inline]
       __sock_sendmsg net/socket.c:802 [inline]
       ____sys_sendmsg+0x9b9/0xa20 net/socket.c:2699
       ___sys_sendmsg+0x2a5/0x360 net/socket.c:2753
       __sys_sendmsg net/socket.c:2785 [inline]
       __do_sys_sendmsg net/socket.c:2790 [inline]
       __se_sys_sendmsg net/socket.c:2788 [inline]
       __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2788
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->q_usage_counter(io)#49){++++}-{0:0}:
       blk_alloc_queue+0x544/0x690 block/blk-core.c:461
       blk_mq_alloc_queue block/blk-mq.c:4453 [inline]
       __blk_mq_alloc_disk+0x194/0x390 block/blk-mq.c:4500
       nbd_dev_add+0x494/0xb60 drivers/block/nbd.c:1954
       nbd_init+0x15f/0x1e0 drivers/block/nbd.c:2692
       do_one_initcall+0x250/0x870 init/main.c:1392
       do_initcall_level+0x10a/0x1a0 init/main.c:1454
       do_initcalls+0x59/0xa0 init/main.c:1470
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1703
       kernel_init+0x1d/0x1d0 init/main.c:1593
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4320 [inline]
       fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4334
       might_alloc include/linux/sched/mm.h:317 [inline]
       slab_pre_alloc_hook mm/slub.c:4521 [inline]
       slab_alloc_node mm/slub.c:4876 [inline]
       kmem_cache_alloc_noprof+0x40/0x650 mm/slub.c:4906
       mt_alloc_one lib/maple_tree.c:139 [inline]
       mas_alloc_nodes+0x291/0x350 lib/maple_tree.c:1089
       mas_preallocate+0x2cf/0x630 lib/maple_tree.c:4961
       vma_iter_prealloc mm/vma.h:577 [inline]
       vma_link+0x123/0x470 mm/vma.c:1849
       insert_vm_struct+0x1bf/0x290 mm/vma.c:3325
       create_init_stack_vma+0x5c1/0x9b0 mm/vma_exec.c:147
       bprm_mm_init fs/exec.c:274 [inline]
       alloc_bprm+0x46f/0x5a0 fs/exec.c:1457
       class_bprm_constructor fs/exec.c:1467 [inline]
       kernel_execve+0x85/0x9b0 fs/exec.c:1859
       try_to_run_init_process+0x13/0x60 init/main.c:1521
       kernel_init+0xad/0x1d0 init/main.c:1649
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (&mm->mmap_lock){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x1520/0x2cd0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
       gup_fast_fallback+0x226/0x20d0 mm/gup.c:3193
       __iov_iter_get_pages_alloc+0x378/0xa40 lib/iov_iter.c:1091
       iov_iter_get_pages2+0x5e/0xa0 lib/iov_iter.c:1137
       sk_msg_zerocopy_from_iter+0x21b/0x8c0 net/core/skmsg.c:328
       tls_sw_sendmsg_locked net/tls/tls_sw.c:1150 [inline]
       tls_sw_sendmsg+0xa19/0x2400 net/tls/tls_sw.c:1302
       sock_sendmsg_nosec net/socket.c:787 [inline]
       __sock_sendmsg net/socket.c:802 [inline]
       __sys_sendto+0x4a3/0x710 net/socket.c:2266
       __do_sys_sendto net/socket.c:2273 [inline]
       __se_sys_sendto net/socket.c:2269 [inline]
       __x64_sys_sendto+0xde/0x100 net/socket.c:2269
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 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:
  &mm->mmap_lock --> &nsock->tx_lock --> sk_lock-AF_INET6

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sk_lock-AF_INET6);
                               lock(&nsock->tx_lock);
                               lock(sk_lock-AF_INET6);
  rlock(&mm->mmap_lock);

 *** DEADLOCK ***

2 locks held by syz.1.2126/13673:
 #0: ffff88802bddb4e8 (&ctx->tx_lock){+.+.}-{4:4}, at: tls_sw_sendmsg+0x12e/0x2400 net/tls/tls_sw.c:1298
 #1: ffff8880359d8fe0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #1: ffff8880359d8fe0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: tls_sw_sendmsg+0x15e/0x2400 net/tls/tls_sw.c:1301

stack backtrace:
CPU: 1 UID: 0 PID: 13673 Comm: syz.1.2126 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x1520/0x2cd0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 gup_fast_fallback+0x226/0x20d0 mm/gup.c:3193
 __iov_iter_get_pages_alloc+0x378/0xa40 lib/iov_iter.c:1091
 iov_iter_get_pages2+0x5e/0xa0 lib/iov_iter.c:1137
 sk_msg_zerocopy_from_iter+0x21b/0x8c0 net/core/skmsg.c:328
 tls_sw_sendmsg_locked net/tls/tls_sw.c:1150 [inline]
 tls_sw_sendmsg+0xa19/0x2400 net/tls/tls_sw.c:1302
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 __sys_sendto+0x4a3/0x710 net/socket.c:2266
 __do_sys_sendto net/socket.c:2273 [inline]
 __se_sys_sendto net/socket.c:2269 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2269
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f704335d68e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f70441ffe88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f70442016c0 RCX: 00007f704335d68e
RDX: 0000000000000020 RSI: 00007f7044200000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f70441fff04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f70441fff58 R14: 00007f7044200000 R15: 0000000000000000
 </TASK>