From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Simon Horman <horms@verge.net.au>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>, kexec@lists.infradead.org
Subject: [PATCH v2] kexec: Fix off-by-one errors in locate_hole()
Date: Wed, 2 Oct 2013 10:42:27 +0200 [thread overview]
Message-ID: <1380703348-5877-1-git-send-email-geert@linux-m68k.org> (raw)
When calling locate_hole() with "hole_size" equal to the size of an
available memory block, it fails to use that memory block.
"end" and "hole_max" point to the last byte within the range, hence
- "size = end - start" is one less than "hole_size",
- "hole_base + hole_size" is one more than "hole_max".
Subtract one from "hole_size" when doing the comparison (adding 1 to "size"
could overflow in case of one big range covering the whole address space).
But explicitly check if "hole_size" is zero first, to handle this case
without causing underflows.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
v2: Accept hole_size == zero.
kexec/kexec.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kexec/kexec.c b/kexec/kexec.c
index 2b98ef055a15..185c85bef342 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -270,7 +270,7 @@ unsigned long locate_hole(struct kexec_info *info,
}
/* Is there enough space left so we can use it? */
size = end - start;
- if (size >= hole_size) {
+ if (!hole_size || size >= hole_size - 1) {
if (hole_end > 0) {
hole_base = start;
break;
@@ -286,7 +286,7 @@ unsigned long locate_hole(struct kexec_info *info,
"0x%lx bytes...\n", hole_size);
return ULONG_MAX;
}
- if ((hole_base + hole_size) > hole_max) {
+ if (hole_size && (hole_base + hole_size - 1) > hole_max) {
fprintf(stderr, "Could not find a free area of memory below: "
"0x%lx...\n", hole_max);
return ULONG_MAX;
--
1.7.9.5
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next reply other threads:[~2013-10-02 8:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-02 8:42 Geert Uytterhoeven [this message]
2013-10-03 1:15 ` [PATCH v2] kexec: Fix off-by-one errors in locate_hole() Simon Horman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1380703348-5877-1-git-send-email-geert@linux-m68k.org \
--to=geert@linux-m68k.org \
--cc=horms@verge.net.au \
--cc=kexec@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox