WARNING: suspicious RCU usage in tipc_l2_send_msg

WARNING: suspicious RCU usage in tipc_l2_send_msg

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    b835a71e usbnet: smsc95xx: Fix use-after-free after removal
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=1095a51d100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dcc6334acae363d4
dashboard link: https://syzkaller.appspot.com/bug?extid=47bbc6b678d317cccbe0
compiler:       gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+47bbc6b678d317cccbe0@syzkaller.appspotmail.com

=============================
WARNING: suspicious RCU usage
5.8.0-rc1-syzkaller #0 Not tainted
-----------------------------
net/tipc/bearer.c:466 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/0:16/19143:
 #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90006f9fda8 ((work_completion)(&cpu_queue->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244

stack backtrace:
CPU: 0 PID: 19143 Comm: kworker/0:16 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: cryptd cryptd_queue_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 tipc_l2_send_msg+0x354/0x420 net/tipc/bearer.c:466
 tipc_aead_encrypt_done+0x204/0x3a0 net/tipc/crypto.c:761
 cryptd_aead_crypt+0xe8/0x1d0 crypto/cryptd.c:739
 cryptd_queue_worker+0x118/0x1b0 crypto/cryptd.c:181
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

Re: WARNING: suspicious RCU usage in tipc_l2_send_msg

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit:    4437dd6e Merge tag 'io_uring-5.8-2020-07-12' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b7869f100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=66ad203c2bb6d8b
dashboard link: https://syzkaller.appspot.com/bug?extid=47bbc6b678d317cccbe0
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10c005af100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+47bbc6b678d317cccbe0@syzkaller.appspotmail.com

=============================
WARNING: suspicious RCU usage
5.8.0-rc4-syzkaller #0 Not tainted
-----------------------------
net/tipc/bearer.c:466 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/0:1/12:
 #0: ffff88821adc9538 ((wq_completion)cryptd){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff88821adc9538 ((wq_completion)cryptd){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff88821adc9538 ((wq_completion)cryptd){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff88821adc9538 ((wq_completion)cryptd){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff88821adc9538 ((wq_completion)cryptd){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff88821adc9538 ((wq_completion)cryptd){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90000d2fda8 ((work_completion)(&cpu_queue->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244

stack backtrace:
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.8.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: cryptd cryptd_queue_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 tipc_l2_send_msg+0x354/0x420 net/tipc/bearer.c:466
 tipc_aead_encrypt_done+0x204/0x3a0 net/tipc/crypto.c:761
 cryptd_aead_crypt+0xe8/0x1d0 crypto/cryptd.c:739
 cryptd_queue_worker+0x118/0x1b0 crypto/cryptd.c:181
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Re: WARNING: suspicious RCU usage in tipc_l2_send_msg

[syzbot]

syzbot has bisected this issue to:

commit 786a2aa281f4c4ba424ea8b8ea1e85ab62c4a57c
Author: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Date:   Mon Jul 6 20:53:42 2020 +0000

    Revert commit e918e570415c ("tpm_tis: Remove the HID IFX0102")

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12fc36d6900000
start commit:   4437dd6e Merge tag 'io_uring-5.8-2020-07-12' of git://git...
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=11fc36d6900000
console output: https://syzkaller.appspot.com/x/log.txt?x=16fc36d6900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=66ad203c2bb6d8b
dashboard link: https://syzkaller.appspot.com/bug?extid=47bbc6b678d317cccbe0
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10c005af100000

Reported-by: syzbot+47bbc6b678d317cccbe0@syzkaller.appspotmail.com
Fixes: 786a2aa281f4 ("Revert commit e918e570415c ("tpm_tis: Remove the HID IFX0102")")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: WARNING: suspicious RCU usage in tipc_l2_send_msg

[Xin Long]

On Sat, Jun 27, 2020 at 1:25 AM syzbot
<syzbot+47bbc6b678d317cccbe0@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    b835a71e usbnet: smsc95xx: Fix use-after-free after removal
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=1095a51d100000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=dcc6334acae363d4
> dashboard link: https://syzkaller.appspot.com/bug?extid=47bbc6b678d317cccbe0
> compiler:       gcc (GCC) 10.1.0-syz 20200507
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+47bbc6b678d317cccbe0@syzkaller.appspotmail.com
>
> =============================
> WARNING: suspicious RCU usage
> 5.8.0-rc1-syzkaller #0 Not tainted
> -----------------------------
> net/tipc/bearer.c:466 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 2, debug_locks = 1
> 2 locks held by kworker/0:16/19143:
>  #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
>  #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
>  #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
>  #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
>  #0: ffff8880a6901d38 ((wq_completion)cryptd){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
>  #1: ffffc90006f9fda8 ((work_completion)(&cpu_queue->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
>
> stack backtrace:
> CPU: 0 PID: 19143 Comm: kworker/0:16 Not tainted 5.8.0-rc1-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Workqueue: cryptd cryptd_queue_worker
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x18f/0x20d lib/dump_stack.c:118
>  tipc_l2_send_msg+0x354/0x420 net/tipc/bearer.c:466
>  tipc_aead_encrypt_done+0x204/0x3a0 net/tipc/crypto.c:761
>  cryptd_aead_crypt+0xe8/0x1d0 crypto/cryptd.c:739
>  cryptd_queue_worker+0x118/0x1b0 crypto/cryptd.c:181
>  process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
>  worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
>  kthread+0x3b5/0x4a0 kernel/kthread.c:291
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
>
Like in bearer.c, rcu_read_lock() is needed before calling
b->media->send_msg() in tipc_aead_encrypt_done():

@@ -757,10 +757,12 @@ static void tipc_aead_encrypt_done(struct
crypto_async_request *base, int err)
        switch (err) {
        case 0:
                this_cpu_inc(tx->stats->stat[STAT_ASYNC_OK]);
+               rcu_read_lock();
                if (likely(test_bit(0, &b->up)))
                        b->media->send_msg(net, skb, b, &tx_ctx->dst);
                else
                        kfree_skb(skb);
+               rcu_read_unlock();
                break;
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.