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From: Andrew Morton <akpm@linux-foundation.org>
To: Joel Savitz <jsavitz@redhat.com>
Cc: linux-kernel@vger.kernel.org, Rafael Aquini <aquini@redhat.com>,
	David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org
Subject: Re: [RESEND PATCH v2] mm/oom_killer: Add task UID to info message on an oom kill
Date: Wed, 12 Jun 2019 18:00:31 -0700	[thread overview]
Message-ID: <20190612180031.e9314711c9d0c77ba915d977@linux-foundation.org> (raw)
In-Reply-To: <1560362273-534-1-git-send-email-jsavitz@redhat.com>

On Wed, 12 Jun 2019 13:57:53 -0400 Joel Savitz <jsavitz@redhat.com>
wrote:

> In the event of an oom kill, useful information about the killed
> process is printed to dmesg. Users, especially system administrators,
> will find it useful to immediately see the UID of the process.
> 
> In the following example, abuse_the_ram is the name of a program
> that attempts to iteratively allocate all available memory until it is
> stopped by force.
> 
> Current message:
> 
> Out of memory: Killed process 35389 (abuse_the_ram)
> total-vm:133718232kB, anon-rss:129624980kB, file-rss:0kB,
> shmem-rss:0kB
> 
> Patched message:
> 
> Out of memory: Killed process 2739 (abuse_the_ram),
> total-vm:133880028kB, anon-rss:129754836kB, file-rss:0kB,
> shmem-rss:0kB, UID 0

The other fields are name:value so it seems better to make the UID
field conform.

Also, there's no typesafe way of printing a uid_t (using the printk %p trick)
so yes, we have to assume its type.  But assuming unsigned int is
better than assuming int!

So...



s/UID %d/UID:%u/ in printk

--- a/mm/oom_kill.c~mm-oom_killer-add-task-uid-to-info-message-on-an-oom-kill-fix
+++ a/mm/oom_kill.c
@@ -876,7 +876,7 @@ static void __oom_kill_process(struct ta
 	 */
 	do_send_sig_info(SIGKILL, SEND_SIG_PRIV, victim, PIDTYPE_TGID);
 	mark_oom_victim(victim);
-	pr_err("%s: Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB, UID %d\n",
+	pr_err("%s: Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB, UID:%u\n",
 		message, task_pid_nr(victim), victim->comm,
 		K(victim->mm->total_vm),
 		K(get_mm_counter(victim->mm, MM_ANONPAGES)),
_


  parent reply	other threads:[~2019-06-13  1:00 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-12 17:57 [RESEND PATCH v2] mm/oom_killer: Add task UID to info message on an oom kill Joel Savitz
2019-06-12 18:40 ` Rafael Aquini
2019-06-13  1:00 ` Andrew Morton [this message]
2019-06-13  8:23 ` Michal Hocko
2019-09-21  0:13   ` Andrew Morton
2019-09-21  1:00     ` Rafael Aquini

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