====================================================== WARNING: possible circular locking dependency detected 6.0.0-syzkaller-00372-ga5088ee7251e #0 Not tainted ------------------------------------------------------ kworker/u4:27/14295 is trying to acquire lock: ffff888022948fb0 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline] ffff888022948fb0 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: tcp_sock_set_cork+0x16/0x90 net/ipv4/tcp.c:3337 but task is already holding lock: ffffc90004a4fda8 ((work_completion)(&(&cp->cp_send_w)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 ((work_completion)(&(&cp->cp_send_w)->work)){+.+.}-{0:0}: __flush_work+0x105/0xae0 kernel/workqueue.c:3069 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160 rds_tcp_reset_callbacks+0x1cb/0x4d0 net/rds/tcp.c:171 rds_tcp_accept_one+0x9d5/0xd10 net/rds/tcp_listen.c:203 rds_tcp_accept_worker+0x55/0x80 net/rds/tcp.c:529 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #0 (k-sk_lock-AF_INET6){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 lock_sock_nested+0x36/0xf0 net/core/sock.c:3393 lock_sock include/net/sock.h:1712 [inline] tcp_sock_set_cork+0x16/0x90 net/ipv4/tcp.c:3337 rds_send_xmit+0x386/0x2540 net/rds/send.c:194 rds_send_worker+0x92/0x2e0 net/rds/threads.c:200 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((work_completion)(&(&cp->cp_send_w)->work)); lock(k-sk_lock-AF_INET6); lock((work_completion)(&(&cp->cp_send_w)->work)); lock(k-sk_lock-AF_INET6); *** DEADLOCK *** 2 locks held by kworker/u4:27/14295: #0: ffff888027f19938 ((wq_completion)krdsd){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888027f19938 ((wq_completion)krdsd){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888027f19938 ((wq_completion)krdsd){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff888027f19938 ((wq_completion)krdsd){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline] #0: ffff888027f19938 ((wq_completion)krdsd){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline] #0: ffff888027f19938 ((wq_completion)krdsd){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260 #1: ffffc90004a4fda8 ((work_completion)(&(&cp->cp_send_w)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264 stack backtrace: CPU: 0 PID: 14295 Comm: kworker/u4:27 Not tainted 6.0.0-syzkaller-00372-ga5088ee7251e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: krdsd rds_send_worker Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 lock_sock_nested+0x36/0xf0 net/core/sock.c:3393 lock_sock include/net/sock.h:1712 [inline] tcp_sock_set_cork+0x16/0x90 net/ipv4/tcp.c:3337 rds_send_xmit+0x386/0x2540 net/rds/send.c:194 rds_send_worker+0x92/0x2e0 net/rds/threads.c:200 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306