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authorJan Kara <jack@suse.cz>2015-11-23 13:09:51 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2015-11-23 21:15:30 -0500
commitc2489e07c0a71a56fb2c84bc0ee66cddfca7d068 (patch)
tree3c79aaf1df2abc9ccdb6e9231cda607211d523fc /fs/splice.c
parentvfs: Make sendfile(2) killable even better (diff)
downloadlinux-dev-c2489e07c0a71a56fb2c84bc0ee66cddfca7d068.tar.xz
linux-dev-c2489e07c0a71a56fb2c84bc0ee66cddfca7d068.zip
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 <dvyukov@google.com> CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/splice.c')
-rw-r--r--fs/splice.c1
1 files changed, 1 insertions, 0 deletions
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);