Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
* 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: syzbot+4596e1fcf98efa7d1745@syzkaller.appspotmail.com

=============================
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 syzkaller@googlegroups.com.

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: syzbot+4596e1fcf98efa7d1745@syzkaller.appspotmail.com
> 
> =============================
> 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 syzkaller@googlegroups.com.
> 
> 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: syzbot+4596e1fcf98efa7d1745@syzkaller.appspotmail.com
>>
>> =============================
>> 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 <axboe@kernel.dk> 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: syzbot+4596e1fcf98efa7d1745@syzkaller.appspotmail.com
> >>
> >> =============================
> >> 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

end of thread, back to index

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
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

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git