This is a note to let you know that I've just added the patch titled
vfs,mm: fix return value of read() at s_maxbytes
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vfs-mm-fix-return-value-of-read-at-s_maxbytes.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d05c5f7ba164aed3db02fb188c26d0dd94f5455b Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date: Wed, 14 Dec 2016 12:45:25 -0800
Subject: vfs,mm: fix return value of read() at s_maxbytes
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
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 <joseph.salisbury@xxxxxxxxxxxxx>
Cc: Wei Fang <fangwei1@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1686,7 +1686,7 @@ static ssize_t do_generic_file_read(stru
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;
Patches currently in stable-queue which might be from torvalds@xxxxxxxxxxxxxxxxxxxx are
queue-4.9/mm-page_alloc-keep-pcp-count-and-list-contents-in-sync-if-struct-page-is-corrupted.patch
queue-4.9/splice-reinstate-sigpipe-epipe-handling.patch
queue-4.9/mm-vmscan.c-set-correct-defer-count-for-shrinker.patch
queue-4.9/vfs-mm-fix-return-value-of-read-at-s_maxbytes.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html