2019-04-26 19:02:43

by Joel Savitz

Subject: [PATCH v2] mm/oom_killer: Add task UID to info message on an oom kill

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

Signed-off-by: Joel Savitz <[email protected]>
---
mm/oom_kill.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3a2484884cfd..af2e3faa72a0 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -874,12 +874,13 @@ static void __oom_kill_process(struct task_struct *victim, const char *message)
*/
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\n",
+ pr_err("%s: Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB, UID %d\n",
message, task_pid_nr(victim), victim->comm,
K(victim->mm->total_vm),
K(get_mm_counter(victim->mm, MM_ANONPAGES)),
K(get_mm_counter(victim->mm, MM_FILEPAGES)),
- K(get_mm_counter(victim->mm, MM_SHMEMPAGES)));
+ K(get_mm_counter(victim->mm, MM_SHMEMPAGES)),
+ from_kuid(&init_user_ns, task_uid(victim)));
task_unlock(victim);

/*
--
2.18.1

2019-04-27 01:17:43

by Rafael Aquini

Subject: Re: [PATCH v2] mm/oom_killer: Add task UID to info message on an oom kill

On Fri, Apr 26, 2019 at 02:59:57PM -0400, Joel Savitz 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
>
> Signed-off-by: Joel Savitz <[email protected]>
> ---
> mm/oom_kill.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 3a2484884cfd..af2e3faa72a0 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -874,12 +874,13 @@ static void __oom_kill_process(struct task_struct *victim, const char *message)
> */
> 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\n",
> + pr_err("%s: Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB, UID %d\n",
> message, task_pid_nr(victim), victim->comm,
> K(victim->mm->total_vm),
> K(get_mm_counter(victim->mm, MM_ANONPAGES)),
> K(get_mm_counter(victim->mm, MM_FILEPAGES)),
> - K(get_mm_counter(victim->mm, MM_SHMEMPAGES)));
> + K(get_mm_counter(victim->mm, MM_SHMEMPAGES)),
> + from_kuid(&init_user_ns, task_uid(victim)));
> task_unlock(victim);
>
> /*
> --
> 2.18.1
>
Acked-by: Rafael Aquini <[email protected]>