2019-12-02 08:15:44

by Zhang Yi

[permalink] [raw]
Subject: [PATCH 4.4 7/7] fs/proc/array.c: allow reporting eip/esp for all coredumping threads

From: John Ogness <[email protected]>

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/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Fixes: fd7d56270b526ca3 ("fs/proc: Report eip/esp in /prod/PID/stat for coredumping")
Signed-off-by: John Ogness <[email protected]>
Reported-by: Jan Luebbe <[email protected]>
Tested-by: Jan Luebbe <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: zhangyi (F) <[email protected]>
---
fs/proc/array.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 42e33ea50d1c..6238f45eed02 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -434,7 +434,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
* 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);
--
2.17.2