From c2489e07c0a71a56fb2c84bc0ee66cddfca7d068 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 22adbbe51e52..4cf700d50b40 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); -- GitLab