From: John Ogness <john.ogness@linutronix.de>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
kernel test robot <rong.a.chen@intel.com>
Cc: Petr Mladek <pmladek@suse.com>,
Peter Zijlstra <peterz@infradead.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrea Parri <parri.andrea@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Paul McKenney <paulmck@kernel.org>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
lkp@lists.01.org
Subject: Re: [printk] 18a2dc6982: ltp.kmsg01.fail
Date: Thu, 09 Jul 2020 12:20:35 +0206 [thread overview]
Message-ID: <874kqhm1v8.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <20200709083323.GA572@jagdpanzerIV.localdomain>
On 2020-07-09, Sergey Senozhatsky <sergey.senozhatsky@gmail.com> wrote:
> On (20/07/09 15:14), kernel test robot wrote:
> [..]
>
> Took me a while to find the FAIL-ed test:
>
>> kmsg01.c:393: INFO: TEST: read returns EPIPE when messages get overwritten
>> kmsg01.c:398: INFO: first seqno: 0
>> kmsg01.c:411: INFO: first seqno now: 881
>> kmsg01.c:425: FAIL: read returned: 77: SUCCESS (0)
>
> So this is seq number related
> https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/logging/kmsg/kmsg01.c#L383
Excellent test.
Since the messages are above the expected average size, the dataring is
wrapping before the descriptor ring. This means that the initial
descriptors are still there, but their data is gone. Initially I would
generate an EPIPE for this, but it was changed. Here is the thread [0]
we had about this.
I have some ideas how to correctly handle this. Let me try some
alternatives and post a proposed solution.
John Ogness
[0] https://lkml.kernel.org/r/20200213090757.GA36551@google.com
next prev parent reply other threads:[~2020-07-09 10:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 14:59 [PATCH v4 0/4] printk: replace ringbuffer John Ogness
2020-07-07 14:59 ` [PATCH v4 1/4] crash: add VMCOREINFO macro to define offset in a struct declared by typedef John Ogness
2020-07-07 14:59 ` [PATCH v4 2/4] printk: add lockless ringbuffer John Ogness
2020-07-07 14:59 ` [PATCH v4 3/4] Revert "printk: lock/unlock console only for new logbuf entries" John Ogness
2020-07-08 14:34 ` Petr Mladek
2020-07-09 1:20 ` Sergey Senozhatsky
2020-07-07 14:59 ` [PATCH v4 4/4] printk: use the lockless ringbuffer John Ogness
2020-07-07 19:25 ` kernel test robot
2020-07-08 13:18 ` John Ogness
2020-07-08 14:35 ` Petr Mladek
2020-07-08 19:24 ` kernel test robot
2020-07-09 7:14 ` [printk] 18a2dc6982: ltp.kmsg01.fail kernel test robot
2020-07-09 8:33 ` Sergey Senozhatsky
2020-07-09 10:14 ` John Ogness [this message]
2020-07-09 10:59 ` Petr Mladek
2020-07-09 11:13 ` Petr Mladek
2020-07-09 11:17 ` John Ogness
2020-07-09 12:25 ` Petr Mladek
2020-07-09 13:07 ` Sergey Senozhatsky
2020-07-09 14:41 ` Petr Mladek
2020-07-08 15:20 ` [PATCH v4 0/4] printk: replace ringbuffer Petr Mladek
2020-07-09 7:03 ` John Ogness
2020-07-10 9:11 ` Petr Mladek
2020-07-10 9:52 ` John Ogness
2020-07-10 14:15 ` Petr Mladek
2020-07-14 2:56 ` Sergey Senozhatsky
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