From: Pavel Begunkov <[email protected]>
To: Josef <[email protected]>, Jens Axboe <[email protected]>,
io-uring <[email protected]>
Cc: [email protected]
Subject: Re: Using SQPOLL for-5.11/io_uring kernel NULL pointer dereference
Date: Sat, 7 Nov 2020 12:10:25 +0000 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAAss7+rt_mkHhGY=kkduDK58jVZy73yZx8qFYEPOU9JjGaCs=g@mail.gmail.com>
On 07/11/2020 00:51, Josef wrote:
> On Sat, 7 Nov 2020 at 01:45, Josef <[email protected]> wrote:
>> I came across some strange behaviour in some netty-io_uring tests when
>> using SQPOLL which seems like a bug to me, however I don't know how to
>> reproduce it, as the error occurs randomly which leads to a kernel
>> "freeze", I spend all day trying to figure out how to reproduce this
>> error...any idea what the cause is?
>>
>> branch: for-5.11/io_uring
>> last commit 34f98f655639b32f28c30c27dbbea57f8c304d9c
>>
>> (please don't waste your time as I'll take a look on the weekend)
>>
> I forgot to mention that same cores are running at 100% cpu usage,
> when error occurs
I haven't got the first email, is it "kernel NULL pointer dereference"
as in the subject or just freeze?
also
- anything in dmesg? (>5 min after freeze)
- did you locate which test hangs it? If so what it uses? e.g. SQPOLL
sharing, IOPOLL., etc.
- is it send/recvmsg, send/recv you use? any other?
- does this happen often?
- you may try `funcgraph __io_sq_thread -H` or even with `io_sq_thread`
(funcgraph is from bpftools). Or catch that with some other tools.
--
Pavel Begunkov
next prev parent reply other threads:[~2020-11-07 12:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAAss7+pgQN7uPFaLakd+K4yZH6TRcMHELQV0wAA2NUxPpYEL_Q@mail.gmail.com>
2020-11-07 0:51 ` Using SQPOLL for-5.11/io_uring kernel NULL pointer dereference Josef
2020-11-07 12:10 ` Pavel Begunkov [this message]
2020-11-07 14:09 ` Josef
2020-11-07 16:28 ` Pavel Begunkov
2020-11-07 20:03 ` Pavel Begunkov
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