syzbot


WARNING: suspicious RCU usage in do_ipv6_setsockopt

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: 544d, last: 544d

Sample crash report:
=============================
WARNING: suspicious RCU usage
5.12.0-rc4-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8294 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.4/8410.

stack backtrace:
CPU: 1 PID: 8410 Comm: syz-executor.4 Not tainted 5.12.0-rc4-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:8294
 __might_fault+0x6e/0x180 mm/memory.c:5018
 _copy_from_user+0x27/0x180 lib/usercopy.c:13
 copy_from_user include/linux/uaccess.h:192 [inline]
 copy_from_sockptr_offset include/linux/sockptr.h:48 [inline]
 copy_from_sockptr include/linux/sockptr.h:55 [inline]
 do_ipv6_setsockopt.constprop.0+0x468/0x41f0 net/ipv6/ipv6_sockglue.c:405
 ipv6_setsockopt+0xd6/0x180 net/ipv6/ipv6_sockglue.c:1003
 tcp_setsockopt+0x136/0x24a0 net/ipv4/tcp.c:3643
 __sys_setsockopt+0x2db/0x610 net/socket.c:2117
 __do_sys_setsockopt net/socket.c:2128 [inline]
 __se_sys_setsockopt net/socket.c:2125 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x467a9a
Code: 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 36 00 00 00 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:00007ffd50bc15d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000029 RCX: 0000000000467a9a
RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 00007ffd50bc1600 R08: 0000000000000558 R09: 0079746972756365
R10: 0000000000542920 R11: 0000000000000206 R12: 00007ffd50bc1660
R13: 0000000000000003 R14: 00007ffd50bc15fc R15: 00000000005428c0

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2021/03/29 03:44 upstream 81b1d39fd39a a8529b82 .config log report info WARNING: suspicious RCU usage in do_ipv6_setsockopt
* Struck through repros no longer work on HEAD.