From 2c5816b4beccc8ba709144539f6fdd764f8fa49c Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 10 Nov 2015 10:32:36 +0100 Subject: cuse: fix memory leak The problem is that fuse_dev_alloc() acquires an extra reference to cc.fc, and the original ref count is never dropped. Reported-by: Colin Ian King Signed-off-by: Miklos Szeredi Fixes: cc080e9e9be1 ("fuse: introduce per-instance fuse_dev structure") Cc: # v4.2+ --- fs/fuse/cuse.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs') diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c index eae2c11268bc..8e3ee1936c7e 100644 --- a/fs/fuse/cuse.c +++ b/fs/fuse/cuse.c @@ -549,6 +549,8 @@ static int cuse_channel_release(struct inode *inode, struct file *file) unregister_chrdev_region(cc->cdev->dev, 1); cdev_del(cc->cdev); } + /* Base reference is now owned by "fud" */ + fuse_conn_put(&cc->fc); rc = fuse_dev_release(inode, file); /* puts the base reference */ -- cgit v1.2.3 From 3ca8138f014a913f98e6ef40e939868e1e9ea876 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Mon, 12 Oct 2015 16:33:44 +0300 Subject: fuse: break infinite loop in fuse_fill_write_pages() I got a report about unkillable task eating CPU. Further investigation shows, that the problem is in the fuse_fill_write_pages() function. If iov's first segment has zero length, we get an infinite loop, because we never reach iov_iter_advance() call. Fix this by calling iov_iter_advance() before repeating an attempt to copy data from userspace. A similar problem is described in 124d3b7041f ("fix writev regression: pan hanging unkillable and un-straceable"). If zero-length segmend is followed by segment with invalid address, iov_iter_fault_in_readable() checks only first segment (zero-length), iov_iter_copy_from_user_atomic() skips it, fails at second and returns zero -> goto again without skipping zero-length segment. Patch calls iov_iter_advance() before goto again: we'll skip zero-length segment at second iteraction and iov_iter_fault_in_readable() will detect invalid address. Special thanks to Konstantin Khlebnikov, who helped a lot with the commit description. Cc: Andrew Morton Cc: Maxim Patlasov Cc: Konstantin Khlebnikov Signed-off-by: Roman Gushchin Signed-off-by: Miklos Szeredi Fixes: ea9b9907b82a ("fuse: implement perform_write") Cc: --- fs/fuse/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/fuse/file.c b/fs/fuse/file.c index f523f2f04c19..195476a24148 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1049,6 +1049,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req, tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes); flush_dcache_page(page); + iov_iter_advance(ii, tmp); if (!tmp) { unlock_page(page); page_cache_release(page); @@ -1061,7 +1062,6 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req, req->page_descs[req->num_pages].length = tmp; req->num_pages++; - iov_iter_advance(ii, tmp); count += tmp; pos += tmp; offset += tmp; -- cgit v1.2.3