From a8d3a5b24da10c5d6b7c2bc2ee26def66f9f46ec 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) commit c2489e07c0a71a56fb2c84bc0ee66cddfca7d068 upstream. 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 Signed-off-by: Jan Kara Signed-off-by: Al Viro Signed-off-by: Zefan Li --- fs/splice.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/splice.c b/fs/splice.c index 4e2309ecf899b..8b97331b3b14e 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -935,6 +935,7 @@ 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); -- 2.47.2