* WARNING: suspicious RCU usage in io_init_identity
@ 2020-10-16 8:12 syzbot
2020-10-16 15:02 ` Qian Cai
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2020-10-16 8:12 UTC (permalink / raw)
To: axboe, io-uring, linux-fsdevel, linux-kernel, syzkaller-bugs,
viro
Hello,
syzbot found the following issue on:
HEAD commit: b2926c10 Add linux-next specific files for 20201016
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12fc877f900000
kernel config: https://syzkaller.appspot.com/x/.config?x=6160209582f55fb1
dashboard link: https://syzkaller.appspot.com/bug?extid=4596e1fcf98efa7d1745
compiler: gcc (GCC) 10.1.0-syz 20200507
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
=============================
WARNING: suspicious RCU usage
5.9.0-next-20201016-syzkaller #0 Not tainted
-----------------------------
include/linux/cgroup.h:494 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
no locks held by syz-executor.0/8301.
stack backtrace:
CPU: 0 PID: 8301 Comm: syz-executor.0 Not tainted 5.9.0-next-20201016-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fb lib/dump_stack.c:118
task_css include/linux/cgroup.h:494 [inline]
blkcg_css include/linux/blk-cgroup.h:224 [inline]
blkcg_css include/linux/blk-cgroup.h:217 [inline]
io_init_identity+0x3a9/0x450 fs/io_uring.c:1052
io_uring_alloc_task_context+0x176/0x250 fs/io_uring.c:7730
io_uring_add_task_file+0x10d/0x180 fs/io_uring.c:8653
io_uring_get_fd fs/io_uring.c:9144 [inline]
io_uring_create fs/io_uring.c:9308 [inline]
io_uring_setup+0x2727/0x3660 fs/io_uring.c:9342
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de59
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7e11fe1bf8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 000000000045de59
RDX: 00000000206d4000 RSI: 0000000020000080 RDI: 0000000000000087
RBP: 000000000118c020 R08: 0000000020000040 R09: 0000000020000040
R10: 0000000020000000 R11: 0000000000000206 R12: 00000000206d4000
R13: 0000000020ee7000 R14: 0000000020000040 R15: 0000000020000000
---
This report 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 [email protected].
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: WARNING: suspicious RCU usage in io_init_identity
2020-10-16 8:12 WARNING: suspicious RCU usage in io_init_identity syzbot
@ 2020-10-16 15:02 ` Qian Cai
2020-10-16 15:05 ` Jens Axboe
0 siblings, 1 reply; 4+ messages in thread
From: Qian Cai @ 2020-10-16 15:02 UTC (permalink / raw)
To: axboe; +Cc: io-uring, linux-fsdevel, linux-kernel, syzkaller-bugs, viro,
syzbot
On Fri, 2020-10-16 at 01:12 -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: b2926c10 Add linux-next specific files for 20201016
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=12fc877f900000
> kernel config: https://syzkaller.appspot.com/x/.config?x=6160209582f55fb1
> dashboard link: https://syzkaller.appspot.com/bug?extid=4596e1fcf98efa7d1745
> compiler: gcc (GCC) 10.1.0-syz 20200507
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> =============================
> WARNING: suspicious RCU usage
> 5.9.0-next-20201016-syzkaller #0 Not tainted
> -----------------------------
> include/linux/cgroup.h:494 suspicious rcu_dereference_check() usage!
Introduced by the linux-next commits:
07950f53f85b ("io_uring: COW io_identity on mismatch")
Can't find the patchset was posted anywhere. Anyway, this should fix it?
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1049,7 +1049,9 @@ static void io_init_identity(struct io_identity *id)
id->files = current->files;
id->mm = current->mm;
#ifdef CONFIG_BLK_CGROUP
+ rcu_read_lock();
id->blkcg_css = blkcg_css();
+ rcu_read_unlock();
#endif
id->creds = current_cred();
id->nsproxy = current->nsproxy;
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 2, debug_locks = 1
> no locks held by syz-executor.0/8301.
>
> stack backtrace:
> CPU: 0 PID: 8301 Comm: syz-executor.0 Not tainted 5.9.0-next-20201016-
> syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
> 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x198/0x1fb lib/dump_stack.c:118
> task_css include/linux/cgroup.h:494 [inline]
> blkcg_css include/linux/blk-cgroup.h:224 [inline]
> blkcg_css include/linux/blk-cgroup.h:217 [inline]
> io_init_identity+0x3a9/0x450 fs/io_uring.c:1052
> io_uring_alloc_task_context+0x176/0x250 fs/io_uring.c:7730
> io_uring_add_task_file+0x10d/0x180 fs/io_uring.c:8653
> io_uring_get_fd fs/io_uring.c:9144 [inline]
> io_uring_create fs/io_uring.c:9308 [inline]
> io_uring_setup+0x2727/0x3660 fs/io_uring.c:9342
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x45de59
> Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f
> 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f7e11fe1bf8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9
> RAX: ffffffffffffffda RBX: 0000000020000080 RCX: 000000000045de59
> RDX: 00000000206d4000 RSI: 0000000020000080 RDI: 0000000000000087
> RBP: 000000000118c020 R08: 0000000020000040 R09: 0000000020000040
> R10: 0000000020000000 R11: 0000000000000206 R12: 00000000206d4000
> R13: 0000000020ee7000 R14: 0000000020000040 R15: 0000000020000000
>
>
> ---
> This report 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 [email protected].
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: WARNING: suspicious RCU usage in io_init_identity
2020-10-16 15:02 ` Qian Cai
@ 2020-10-16 15:05 ` Jens Axboe
2020-10-21 10:02 ` Dmitry Vyukov
0 siblings, 1 reply; 4+ messages in thread
From: Jens Axboe @ 2020-10-16 15:05 UTC (permalink / raw)
To: Qian Cai
Cc: io-uring, linux-fsdevel, linux-kernel, syzkaller-bugs, viro,
syzbot
On 10/16/20 9:02 AM, Qian Cai wrote:
> On Fri, 2020-10-16 at 01:12 -0700, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: b2926c10 Add linux-next specific files for 20201016
>> git tree: linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=12fc877f900000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=6160209582f55fb1
>> dashboard link: https://syzkaller.appspot.com/bug?extid=4596e1fcf98efa7d1745
>> compiler: gcc (GCC) 10.1.0-syz 20200507
>>
>> Unfortunately, I don't have any reproducer for this issue yet.
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: [email protected]
>>
>> =============================
>> WARNING: suspicious RCU usage
>> 5.9.0-next-20201016-syzkaller #0 Not tainted
>> -----------------------------
>> include/linux/cgroup.h:494 suspicious rcu_dereference_check() usage!
>
> Introduced by the linux-next commits:
>
> 07950f53f85b ("io_uring: COW io_identity on mismatch")
>
> Can't find the patchset was posted anywhere. Anyway, this should fix it?
It's just in testing... I already folded in this change.
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: WARNING: suspicious RCU usage in io_init_identity
2020-10-16 15:05 ` Jens Axboe
@ 2020-10-21 10:02 ` Dmitry Vyukov
0 siblings, 0 replies; 4+ messages in thread
From: Dmitry Vyukov @ 2020-10-21 10:02 UTC (permalink / raw)
To: Jens Axboe
Cc: Qian Cai, io-uring, linux-fsdevel, LKML, syzkaller-bugs, Al Viro,
syzbot
On Fri, Oct 16, 2020 at 5:05 PM Jens Axboe <[email protected]> wrote:
>
> On 10/16/20 9:02 AM, Qian Cai wrote:
> > On Fri, 2020-10-16 at 01:12 -0700, syzbot wrote:
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit: b2926c10 Add linux-next specific files for 20201016
> >> git tree: linux-next
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=12fc877f900000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=6160209582f55fb1
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=4596e1fcf98efa7d1745
> >> compiler: gcc (GCC) 10.1.0-syz 20200507
> >>
> >> Unfortunately, I don't have any reproducer for this issue yet.
> >>
> >> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> Reported-by: [email protected]
> >>
> >> =============================
> >> WARNING: suspicious RCU usage
> >> 5.9.0-next-20201016-syzkaller #0 Not tainted
> >> -----------------------------
> >> include/linux/cgroup.h:494 suspicious rcu_dereference_check() usage!
> >
> > Introduced by the linux-next commits:
> >
> > 07950f53f85b ("io_uring: COW io_identity on mismatch")
> >
> > Can't find the patchset was posted anywhere. Anyway, this should fix it?
>
> It's just in testing... I already folded in this change.
Now that it's in linux-next we can close this report:
#syz fix: io_uring: COW io_identity on mismatch
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-10-16 8:12 WARNING: suspicious RCU usage in io_init_identity syzbot
2020-10-16 15:02 ` Qian Cai
2020-10-16 15:05 ` Jens Axboe
2020-10-21 10:02 ` Dmitry Vyukov
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