syzbot


WARNING: suspicious RCU usage in count (2)

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: 621d, last: 621d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: suspicious RCU usage in count 1 781d 777d 0/24 auto-closed as invalid on 2021/04/11 19:33

Sample crash report:
=============================
WARNING: suspicious RCU usage
5.13.0-rc2-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8304 Illegal context switch in RCU-bh read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
no locks held by syz-executor.4/14357.

stack backtrace:
CPU: 1 PID: 14357 Comm: syz-executor.4 Not tainted 5.13.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 ___might_sleep+0x229/0x2c0 kernel/sched/core.c:8304
 __might_fault+0x6e/0x180 mm/memory.c:5067
 get_user_arg_ptr.isra.0+0x35/0xc0 fs/exec.c:421
 count.constprop.0+0x17c/0x280 fs/exec.c:436
 do_execveat_common+0x2fd/0x7c0 fs/exec.c:1897
 do_execve fs/exec.c:1987 [inline]
 __do_sys_execve fs/exec.c:2063 [inline]
 __se_sys_execve fs/exec.c:2058 [inline]
 __x64_sys_execve+0x8f/0xc0 fs/exec.c:2058
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f532184f188 EFLAGS: 00000246
 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 00000000200008c0 RSI: 0000000000000000 RDI: 0000000020000700
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe9bb40fdf R14: 00007f532184f300 R15: 0000000000022000

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-kasan-gce-selinux-root 2021/05/21 16:41 upstream 79a106fc6585 3c7fef33 .config console log report info WARNING: suspicious RCU usage in count
* Struck through repros no longer work on HEAD.