The patch titled
Subject: proc, coredump: add CoreDumping flag to /proc/pid/status
has been added to the -mm tree. Its filename is
proc-coredump-add-coredumping-flag-to-proc-pid-status.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-coredump-add-coredumping-flag-to-proc-pid-status.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-coredump-add-coredumping-flag-to-proc-pid-status.patch
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------------------------------------------------------
From: Roman Gushchin <guro@xxxxxx>
Subject: proc, coredump: add CoreDumping flag to /proc/pid/status
Right now there is no convenient way to check if a process is being
coredumped at the moment.
It might be necessary to recognize such state to prevent killing the
process and getting a broken coredump. Writing a large core might take
significant time, and the process is unresponsive during it, so it might
be killed by timeout, if another process is monitoring and
killing/restarting hanging tasks.
To provide an ability to detect if a process is in the state of being
coreduped, we can expose a boolean CoreDumping flag in /proc/pid/status.
Example:
$ cat core.sh
#!/bin/sh
echo "|/usr/bin/sleep 10" > /proc/sys/kernel/core_pattern
sleep 1000 &
PID=$!
cat /proc/$PID/status | grep CoreDumping
kill -ABRT $PID
sleep 1
cat /proc/$PID/status | grep CoreDumping
$ ./core.sh
CoreDumping: 0
CoreDumping: 1
Link: http://lkml.kernel.org/r/20170920230634.31572-1-guro@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/array.c | 6 ++++++
1 file changed, 6 insertions(+)
diff -puN fs/proc/array.c~proc-coredump-add-coredumping-flag-to-proc-pid-status fs/proc/array.c
--- a/fs/proc/array.c~proc-coredump-add-coredumping-flag-to-proc-pid-status
+++ a/fs/proc/array.c
@@ -370,6 +370,11 @@ static void task_cpus_allowed(struct seq
cpumask_pr_args(&task->cpus_allowed));
}
+static inline void task_core_dumping(struct seq_file *m, struct mm_struct *mm)
+{
+ seq_printf(m, "CoreDumping:\t%d\n", !!mm->core_state);
+}
+
int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
@@ -380,6 +385,7 @@ int proc_pid_status(struct seq_file *m,
if (mm) {
task_mem(m, mm);
+ task_core_dumping(m, mm);
mmput(mm);
}
task_sig(m, task);
_
Patches currently in -mm which might be from guro@xxxxxx are
proc-coredump-add-coredumping-flag-to-proc-pid-status.patch
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