From: John Ogness <john.ogn...@linutronix.de>

commit cb8f381f1613cafe3aec30809991cd56e7135d92 upstream.

0a1eb2d474ed ("fs/proc: Stop reporting eip and esp in /proc/PID/stat")
stopped reporting eip/esp and fd7d56270b52 ("fs/proc: Report eip/esp in
/prod/PID/stat for coredumping") reintroduced the feature to fix a
regression with userspace core dump handlers (such as minicoredumper).

Because PF_DUMPCORE is only set for the primary thread, this didn't fix
the original problem for secondary threads.  Allow reporting the eip/esp
for all threads by checking for PF_EXITING as well.  This is set for all
the other threads when they are killed.  coredump_wait() waits for all the
tasks to become inactive before proceeding to invoke a core dumper.

Link: http://lkml.kernel.org/r/87y32p7i7a....@linutronix.de
Link: http://lkml.kernel.org/r/20190522161614.628-1-...@pengutronix.de
Fixes: fd7d56270b526ca3 ("fs/proc: Report eip/esp in /prod/PID/stat for 
coredumping")
Signed-off-by: John Ogness <john.ogn...@linutronix.de>
Reported-by: Jan Luebbe <j...@pengutronix.de>
Tested-by: Jan Luebbe <j...@pengutronix.de>
Cc: Alexey Dobriyan <adobri...@gmail.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 fs/proc/array.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -448,7 +448,7 @@ static int do_task_stat(struct seq_file
                 * a program is not able to use ptrace(2) in that case. It is
                 * safe because the task has stopped executing permanently.
                 */
-               if (permitted && (task->flags & PF_DUMPCORE)) {
+               if (permitted && (task->flags & (PF_EXITING|PF_DUMPCORE))) {
                        if (try_get_task_stack(task)) {
                                eip = KSTK_EIP(task);
                                esp = KSTK_ESP(task);


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