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authorPeter Zijlstra <peterz@infradead.org>2021-04-08 11:46:12 +0200
committerJens Axboe <axboe@kernel.dk>2021-04-08 13:43:53 -0600
commit40c7fd3fdfba97a18724a0b96d132335fd419e98 (patch)
treec7e5ed9dc17a58d49a9f5444c58bd311765d8a40 /block/ioprio.c
parent3212135a718b06be38811f2d9a320ae842e76409 (diff)
block: Fix sys_ioprio_set(.which=IOPRIO_WHO_PGRP) task iteration
do_each_pid_thread() { } while_each_pid_thread() is a double loop and thus break doesn't work as expected. Also, it should be used under tasklist_lock because otherwise we can race against change_pid() for PGID/SID. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/YG7Q5C4Rb5dx5GFx@hirez.programming.kicks-ass.net Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/ioprio.c')
-rw-r--r--block/ioprio.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/block/ioprio.c b/block/ioprio.c
index 364d2294ba90..bee628f9f1b2 100644
--- a/block/ioprio.c
+++ b/block/ioprio.c
@@ -119,11 +119,17 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
pgrp = task_pgrp(current);
else
pgrp = find_vpid(who);
+
+ read_lock(&tasklist_lock);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
ret = set_task_ioprio(p, ioprio);
- if (ret)
- break;
+ if (ret) {
+ read_unlock(&tasklist_lock);
+ goto out;
+ }
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
+ read_unlock(&tasklist_lock);
+
break;
case IOPRIO_WHO_USER:
uid = make_kuid(current_user_ns(), who);
@@ -153,6 +159,7 @@ free_uid:
ret = -EINVAL;
}
+out:
rcu_read_unlock();
return ret;
}