From: Eric Dumazet <[email protected]>
User can pass an arbitrary large buffer to getdents().
It is typically a 32KB buffer used by libc scandir() implementation.
When scanning /proc/{pid}/fd, we can hold cpu way too long,
so add a cond_resched() to be kind with other tasks.
We've seen latencies of more than 50ms on real workloads.
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Alexander Viro <[email protected]>
---
fs/proc/fd.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
index 3c2a915c695a..56afa5ef08f2 100644
--- a/fs/proc/fd.c
+++ b/fs/proc/fd.c
@@ -258,6 +258,7 @@ static int proc_readfd_common(struct file *file, struct
dir_context *ctx,
name, len, instantiate, p,
(void *)(unsigned long)fd))
goto out_fd_loop;
+ cond_resched();
rcu_read_lock();
}
rcu_read_unlock();
--
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