From 47d9f32bf5758df51224a69030c4fde2e3e5e13a Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 23 Nov 2015 13:09:51 +0100 Subject: [PATCH] vfs: Avoid softlockups with sendfile(2) The following test program from Dmitry can cause softlockups or RCU stalls as it copies 1GB from tmpfs into eventfd and we don't have any scheduling point at that path in sendfile(2) implementation: int r1 = eventfd(0, 0); int r2 = memfd_create("", 0); unsigned long n = 1<<30; fallocate(r2, 0, 0, n); sendfile(r1, r2, 0, n); Add cond_resched() into __splice_from_pipe() to fix the problem. CC: Dmitry Vyukov CC: stable@vger.kernel.org Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/splice.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/splice.c b/fs/splice.c index 22adbbe51e52c..4cf700d50b403 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -891,6 +891,7 @@ ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, splice_from_pipe_begin(sd); do { + cond_resched(); ret = splice_from_pipe_next(pipe, sd); if (ret > 0) ret = splice_from_pipe_feed(pipe, sd, actor); -- 2.39.5