syzbot


WARNING: suspicious RCU usage in inet_twsk_purge

Status: fixed on 2021/11/10 00:50
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 3066820034b5 rcu: Reject RCU_LOCKDEP_WARN() false positives
First crash: 546d, last: 444d

Sample crash report:
=============================
WARNING: suspicious RCU usage
5.13.0-rc5-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8304 Illegal context switch in RCU-sched read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
3 locks held by kworker/u4:5/440:
 #0: 
ffff888143d83138
 (
(wq_completion)netns
){+.+.}-{0:0}
, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
, at: set_work_data kernel/workqueue.c:617 [inline]
, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2247
 #1: 
ffffc9000269fda8
 (
net_cleanup_work
){+.+.}-{0:0}
, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2251
 #2: 
ffffffff8d692550
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:557

stack backtrace:
CPU: 0 PID: 440 Comm: kworker/u4:5 Not tainted 5.13.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 ___might_sleep+0x266/0x2c0 kernel/sched/core.c:8304
 inet_twsk_purge+0xe8/0x7c0 net/ipv4/inet_timewait_sock.c:267
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:178
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2276
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2422
 kthread+0x3b1/0x4a0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Crashes (10):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce 2021/06/12 20:29 upstream ad347abe4a98 1ba81399 .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-kasan-gce-root 2021/05/07 11:40 upstream d2b6f8a17919 f6da8120 .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-kasan-gce-smack-root 2021/04/29 11:52 upstream d72cd4ad4174 77e2b668 .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-kasan-gce-root 2021/04/24 18:49 upstream 8db5efb83fa9 17f0b706 .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-kasan-gce-selinux-root 2021/04/20 14:09 upstream 7af08140979a c0ced557 .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-kasan-gce-selinux-root 2021/03/29 23:10 upstream 1e43c377a79f 6a81331a .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-kasan-gce-386 2021/05/14 17:25 upstream 315d99318179 8bdd5343 .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-net-this-kasan-gce 2021/05/10 01:17 net b741596468b0 bc5434be .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-net-kasan-gce 2021/07/10 01:45 net-next 5e437416ff66 8f5a7b8c .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
ci-upstream-net-kasan-gce 2021/06/23 05:22 net-next 38f75922a690 aba2b2fb .config log report info WARNING: suspicious RCU usage in inet_twsk_purge
* Struck through repros no longer work on HEAD.