From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Subject: block: use for_each_thread() in sys_ioprio_set()/sys_ioprio_get()
IOPRIO_WHO_USER case in sys_ioprio_set()/sys_ioprio_get() are using
while_each_thread(), which is unsafe under RCU lock according to commit
0c740d0afc3bff0a ("introduce for_each_thread() to replace the buggy
while_each_thread()"). Use for_each_thread() (via
for_each_process_thread()) which is safe under RCU lock.
Link: http://lkml.kernel.org/r/201702011947.DBD56740.OMVHOLOtSJFFFQ@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1486041779-4401-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
block/ioprio.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff -puN block/ioprio.c~block-use-for_each_thread-in-sys_ioprio_set-sys_ioprio_get block/ioprio.c
--- a/block/ioprio.c~block-use-for_each_thread-in-sys_ioprio_set-sys_ioprio_get
+++ a/block/ioprio.c
@@ -122,14 +122,14 @@ SYSCALL_DEFINE3(ioprio_set, int, which,
if (!user)
break;
- do_each_thread(g, p) {
+ for_each_process_thread(g, p) {
if (!uid_eq(task_uid(p), uid) ||
!task_pid_vnr(p))
continue;
ret = set_task_ioprio(p, ioprio);
if (ret)
goto free_uid;
- } while_each_thread(g, p);
+ }
free_uid:
if (who)
free_uid(user);
@@ -222,7 +222,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which,
if (!user)
break;
- do_each_thread(g, p) {
+ for_each_process_thread(g, p) {
if (!uid_eq(task_uid(p), user->uid) ||
!task_pid_vnr(p))
continue;
@@ -233,7 +233,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which,
ret = tmpio;
else
ret = ioprio_best(ret, tmpio);
- } while_each_thread(g, p);
+ }
if (who)
free_uid(user);
_
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
