From 48466c4772d2cfeb331395043f7edd8c5324ef1b Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 14 Dec 2016 12:45:25 -0800 Subject: vfs,mm: fix return value of read() at s_maxbytes commit d05c5f7ba164aed3db02fb188c26d0dd94f5455b upstream. We truncated the possible read iterator to s_maxbytes in commit c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()"), but our end condition handling was wrong: it's not an error to try to read at the end of the file. Reading past the end should return EOF (0), not EINVAL. See for example https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1649342 http://lists.gnu.org/archive/html/bug-coreutils/2016-12/msg00008.html where a md5sum of a maximally sized file fails because the final read is exactly at s_maxbytes. Fixes: c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()") Reported-by: Joseph Salisbury Cc: Wei Fang Cc: Christoph Hellwig Cc: Dave Chinner Cc: Al Viro Cc: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/filemap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index 50b52fe51937..9a50acecc473 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1686,7 +1686,7 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, int error = 0; if (unlikely(*ppos >= inode->i_sb->s_maxbytes)) - return -EINVAL; + return 0; iov_iter_truncate(iter, inode->i_sb->s_maxbytes); index = *ppos >> PAGE_SHIFT; -- cgit v1.2.3