| Message ID | 1416841599-8119-1-git-send-email-luis.henriques@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/mm/iov_iter.c b/mm/iov_iter.c index 9a09f2034fcc..141dcf796d28 100644 --- a/mm/iov_iter.c +++ b/mm/iov_iter.c @@ -699,9 +699,9 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i) if (i->nr_segs == 1) return i->count; else if (i->type & ITER_BVEC) - return min(i->count, i->iov->iov_len - i->iov_offset); - else return min(i->count, i->bvec->bv_len - i->iov_offset); + else + return min(i->count, i->iov->iov_len - i->iov_offset); } EXPORT_SYMBOL(iov_iter_single_seg_count);
This is a note to let you know that I have just added a patch titled Fix thinko in iov_iter_single_seg_count to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From a2510e5d633485b7a64a107f040945d3a0ffa320 Mon Sep 17 00:00:00 2001 From: Paul Mackerras <paulus@samba.org> Date: Thu, 13 Nov 2014 20:15:23 +1100 Subject: Fix thinko in iov_iter_single_seg_count commit ad0eab9293485d1c06237e9249f6d4dfa3d93d4d upstream. The branches of the if (i->type & ITER_BVEC) statement in iov_iter_single_seg_count() are the wrong way around; if ITER_BVEC is clear then we use i->bvec, when we should be using i->iov. This fixes it. In my case, the symptom that this caused was that a KVM guest doing filesystem operations on a virtual disk would result in one of qemu's threads on the host going into an infinite loop in generic_perform_write(). The loop would hit the copied == 0 case and call iov_iter_single_seg_count() to reduce the number of bytes to try to process, but because of the error, iov_iter_single_seg_count() would just return i->count and the loop made no progress and continued forever. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- mm/iov_iter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 2.1.0