[syzbot] possible deadlock in rds_tcp_reset_callbacks
From: syzbot
Date: Sun Aug 21 2022 - 01:34:39 EST
Hello,
syzbot found the following issue on:
HEAD commit: 8755ae45a9e8 Add linux-next specific files for 20220819
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=107cf485080000
kernel config: https://syzkaller.appspot.com/x/.config?x=ead6107a3bbe3c62
dashboard link: https://syzkaller.appspot.com/bug?extid=78c55c7bc6f66e53dce2
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12e678cb080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13f68e5b080000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+78c55c7bc6f66e53dce2@xxxxxxxxxxxxxxxxxxxxxxxxx
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc1-next-20220819-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:3/46 is trying to acquire lock:
ffff888027dc40e8 ((work_completion)(&(&cp->cp_send_w)->work)){+.+.}-{0:0}, at: __flush_work+0xdd/0xae0 kernel/workqueue.c:3066
but task is already holding lock:
ffff88807e18da70 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline]
ffff88807e18da70 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: rds_tcp_reset_callbacks+0x1bf/0x4d0 net/rds/tcp.c:169
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (k-sk_lock-AF_INET6){+.+.}-{0:0}:
lock_sock_nested+0x36/0xf0 net/core/sock.c:3391
lock_sock include/net/sock.h:1712 [inline]
tcp_sock_set_cork+0x16/0x90 net/ipv4/tcp.c:3328
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
-> #0 ((work_completion)(&(&cp->cp_send_w)->work)){+.+.}-{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
__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
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(k-sk_lock-AF_INET6);
lock((work_completion)(&(&cp->cp_send_w)->work));
lock(k-sk_lock-AF_INET6);
lock((work_completion)(&(&cp->cp_send_w)->work));
*** DEADLOCK ***
4 locks held by kworker/u4:3/46:
#0: ffff8880275f7938 ((wq_completion)krdsd){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8880275f7938 ((wq_completion)krdsd){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff8880275f7938 ((wq_completion)krdsd){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff8880275f7938 ((wq_completion)krdsd){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff8880275f7938 ((wq_completion)krdsd){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff8880275f7938 ((wq_completion)krdsd){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc90000b77da8 ((work_completion)(&rtn->rds_tcp_accept_w)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
#2: ffff8880733c4088 (&tc->t_conn_path_lock){+.+.}-{3:3}, at: rds_tcp_accept_one+0x892/0xd10 net/rds/tcp_listen.c:195
#3: ffff88807e18da70 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline]
#3: ffff88807e18da70 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: rds_tcp_reset_callbacks+0x1bf/0x4d0 net/rds/tcp.c:169
stack backtrace:
CPU: 1 PID: 46 Comm: kworker/u4:3 Not tainted 6.0.0-rc1-next-20220819-syzkaller #0
kworker/u4:3[46] cmdline: ��a�����
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Workqueue: krdsd rds_tcp_accept_worker
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:122 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:140
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
__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
</TASK>
---
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