Greeting,
FYI, we noticed the following commit (built with gcc-9):
commit: 889b7da23abf92faf34491df95733bda63639e32 ("mctp: Add initial routing framework")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
in testcase: trinity
version: trinity-x86_64-da65f0aa-1_20210719
with following parameters:
number: 99999
group: group-00
test-description: Trinity is a linux system call fuzz tester.
test-url: http://codemonkey.org.uk/projects/trinity/
on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
If you fix the issue, kindly add following tag
Reported-by: kernel test robot <[email protected]>
[ 843.495309][ T345]
[ 843.509974][ T345] =============================
[ 843.524220][ T345] WARNING: suspicious RCU usage
[ 843.538791][ T345] 5.14.0-rc2-00606-g889b7da23abf #1 Not tainted
[ 843.553617][ T345] -----------------------------
[ 843.567412][ T345] net/mctp/route.c:310 RCU-list traversed in non-reader section!!
[ 843.583699][ T345]
[ 843.583699][ T345] other info that might help us debug this:
[ 843.583699][ T345]
[ 843.623303][ T345]
[ 843.623303][ T345] rcu_scheduler_active = 2, debug_locks = 1
[ 843.649555][ T345] 3 locks held by kworker/u4:1/345:
[ 843.662935][ T345] #0: ffff917f01b7e548 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x311/0x980
[ 843.678204][ T345] #1: ffffaaf904f77e48 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x311/0x980
[ 843.693346][ T345] #2: ffffffffa54be518 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x4c/0x540
[ 843.708230][ T345]
[ 843.708230][ T345] stack backtrace:
[ 843.734903][ T345] CPU: 1 PID: 345 Comm: kworker/u4:1 Not tainted 5.14.0-rc2-00606-g889b7da23abf #1 8f09027720f43f2fcf70dac5ed9f779ab6f5e57b
[ 843.764085][ T345] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[ 843.779545][ T345] Workqueue: netns cleanup_net
[ 843.793968][ T345] Call Trace:
[ 843.808340][ T345] dump_stack_lvl+0xf9/0x169
[ 843.823211][ T345] mctp_routes_net_exit+0xb6/0xc0
[ 843.837851][ T345] ? mctp_route_release+0xc0/0xc0
[ 843.852553][ T345] ops_exit_list+0x51/0xc0
[ 843.866911][ T345] cleanup_net+0x317/0x540
[ 843.880986][ T345] process_one_work+0x3e7/0x980
[ 843.895489][ T345] worker_thread+0x5b/0x600
[ 843.910180][ T345] ? process_one_work+0x980/0x980
[ 843.925065][ T345] kthread+0x170/0x1c0
[ 843.939268][ T345] ? set_kthread_struct+0x80/0x80
[ 843.953355][ T345] ret_from_fork+0x22/0x30
To reproduce:
# build kernel
cd linux
cp config-5.14.0-rc2-00606-g889b7da23abf .config
make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email
---
0DAY/LKP+ Test Infrastructure Open Source Technology Center
https://lists.01.org/hyperkitty/list/[email protected] Intel Corporation
Thanks,
Oliver Sang
The kernel test robot reports:
[ 843.509974][ T345] =============================
[ 843.524220][ T345] WARNING: suspicious RCU usage
[ 843.538791][ T345] 5.14.0-rc2-00606-g889b7da23abf #1 Not tainted
[ 843.553617][ T345] -----------------------------
[ 843.567412][ T345] net/mctp/route.c:310 RCU-list traversed in non-reader section!!
- we're missing the rcu read lock acquire around the destruction path.
This change adds the acquire/release - the path is already atomic, and
we're using the _rcu list iterators.
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Jeremy Kerr <[email protected]>
---
net/mctp/route.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/mctp/route.c b/net/mctp/route.c
index 5265525011ad..5ca186d53cb0 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -1083,8 +1083,10 @@ static void __net_exit mctp_routes_net_exit(struct net *net)
{
struct mctp_route *rt;
+ rcu_read_lock();
list_for_each_entry_rcu(rt, &net->mctp.routes, list)
mctp_route_release(rt);
+ rcu_read_unlock();
}
static struct pernet_operations mctp_net_ops = {
--
2.30.2
Hello:
This patch was applied to netdev/net.git (refs/heads/master):
On Wed, 8 Sep 2021 12:13:10 +0800 you wrote:
> The kernel test robot reports:
>
> [ 843.509974][ T345] =============================
> [ 843.524220][ T345] WARNING: suspicious RCU usage
> [ 843.538791][ T345] 5.14.0-rc2-00606-g889b7da23abf #1 Not tainted
> [ 843.553617][ T345] -----------------------------
> [ 843.567412][ T345] net/mctp/route.c:310 RCU-list traversed in non-reader section!!
>
> [...]
Here is the summary with links:
- [net] mctp: perform route destruction under RCU read lock
https://git.kernel.org/netdev/net/c/581edcd0c8a0
You are awesome, thank you!
--
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