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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
0c740d0afc ("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@I-love.SAKURA.ne.jp
Link: http://lkml.kernel.org/r/1486041779-4401-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Tetsuo Handa 2017-02-22 15:40:50 -08:00 committed by Linus Torvalds
parent 6302666d2e
commit 612dafabb6
1 changed files with 4 additions and 4 deletions
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8
block/ioprio.c
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@ -122,14 +122,14 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
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, int, who)
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, int, who)
ret = tmpio;
else
ret = ioprio_best(ret, tmpio);
} while_each_thread(g, p);
}
if (who)
free_uid(user);