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From: Simon Horman <horms@kernel.org>
To: Anjali Kulkarni <anjali.k.kulkarni@oracle.com>
Cc: davem@davemloft.net, Liam.Howlett@oracle.com,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	vschneid@redhat.com, jiri@resnulli.us,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	akpm@linux-foundation.org, shuah@kernel.org,
	linux-kselftest@vger.kernel.org, peili.io@oracle.com
Subject: Re: [PATCH net-next v5 0/3] Threads support in proc connector
Date: Fri, 18 Oct 2024 10:49:42 +0100	[thread overview]
Message-ID: <20241018094942.GE1697@kernel.org> (raw)
In-Reply-To: <20241017181436.2047508-1-anjali.k.kulkarni@oracle.com>

On Thu, Oct 17, 2024 at 11:14:33AM -0700, Anjali Kulkarni wrote:
> Recently we committed a fix to allow processes to receive notifications for
> non-zero exits via the process connector module. Commit is a4c9a56e6a2c.
> 
> However, for threads, when it does a pthread_exit(&exit_status) call, the
> kernel is not aware of the exit status with which pthread_exit is called.
> It is sent by child thread to the parent process, if it is waiting in
> pthread_join(). Hence, for a thread exiting abnormally, kernel cannot
> send notifications to any listening processes.
> 
> The exception to this is if the thread is sent a signal which it has not
> handled, and dies along with it's process as a result; for eg. SIGSEGV or
> SIGKILL. In this case, kernel is aware of the non-zero exit and sends a
> notification for it.
> 
> For our use case, we cannot have parent wait in pthread_join, one of the
> main reasons for this being that we do not want to track normal
> pthread_exit(), which could be a very large number. We only want to be
> notified of any abnormal exits. Hence, threads are created with
> pthread_attr_t set to PTHREAD_CREATE_DETACHED.
> 
> To fix this problem, we add a new type PROC_CN_MCAST_NOTIFY to proc connector
> API, which allows a thread to send it's exit status to kernel either when
> it needs to call pthread_exit() with non-zero value to indicate some
> error or from signal handler before pthread_exit().
> 
> We also need to filter packets with non-zero exit notifications futher
> based on instances, which can be identified by task names. Hence, added a
> comm field to the packet's struct proc_event, in which task->comm is
> stored.

As it seems that there will be another revision anyway,
please run this patch-set through checkpatch with the following arguments.

	./scripts/checkpatch.pl --strict --max-line-length=80

And please fix warnings about alignment and line length.
But please do so in such a way that doesn't reduce readability,
e.g. don't split strings over multiple lines.

  parent reply	other threads:[~2024-10-18  9:49 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-17 18:14 [PATCH net-next v5 0/3] Threads support in proc connector Anjali Kulkarni
2024-10-17 18:14 ` [PATCH net-next v5 1/3] connector/cn_proc: Add hash table for threads Anjali Kulkarni
2024-10-17 18:14 ` [PATCH net-next v5 2/3] connector/cn_proc: Kunit tests for threads hash table Anjali Kulkarni
2024-10-18  0:13   ` Stanislav Fomichev
2024-10-18  0:34     ` Anjali Kulkarni
2024-10-18  0:55       ` Stanislav Fomichev
2024-10-18  1:08         ` Anjali Kulkarni
2024-10-18 14:30           ` Stanislav Fomichev
2024-10-22 20:36         ` Anjali Kulkarni
2024-10-22 23:50           ` Stanislav Fomichev
2024-10-23  2:03             ` Anjali Kulkarni
2024-10-23  2:24               ` Anjali Kulkarni
2024-10-23 15:05                 ` Stanislav Fomichev
2024-10-23 15:58                   ` Anjali Kulkarni
2024-10-19  1:28   ` kernel test robot
2024-10-19  2:51   ` kernel test robot
2024-10-17 18:14 ` [PATCH net-next v5 3/3] connector/cn_proc: Selftest for threads Anjali Kulkarni
2024-10-18 10:04   ` Simon Horman
2024-10-18 15:36     ` Anjali Kulkarni
2024-10-18  9:49 ` Simon Horman [this message]
2024-10-18 15:31   ` [PATCH net-next v5 0/3] Threads support in proc connector Anjali Kulkarni

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