From: Dave Young <dyoung@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, d.hatayama@jp.fujitsu.com,
bhe@redhat.com, vgoyal@redhat.com, kexec@lists.infradead.org
Cc: dyoung@redhat.com, nasa4836@gmail.com, mhuang@redhat.com
Subject: [PATCH V2] proc-vmcore: wrong data type casting fix
Date: Fri, 11 Mar 2016 16:42:48 +0800 [thread overview]
Message-ID: <20160311084248.GA9417@dhcp-128-65.nay.redhat.com> (raw)
On i686 PAE enabled machine the contiguous physical area could be large
and it can cause trimming down variables in below calculation in
read_vmcore() and mmap_vmcore():
tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
Then the real size passed down is not correct any more.
Suppose m->offset + m->size - *fpos being truncated to 0, buflen >0 then
we will get tsz = 0. It is of course not an expected result.
During our tests there are two problems caused by it:
1) read_vmcore will refuse to continue so makedumpfile fails.
2) mmap_vmcore will trigger BUG_ON() in remap_pfn_range().
Use unsigned long long in min_t instead so that the variables are not
truncated.
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Dave Young <dyoung@redhat.com>
---
v1->v2: spelling fix in patch log
fs/proc/vmcore.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- linux-x86.orig/fs/proc/vmcore.c
+++ linux-x86/fs/proc/vmcore.c
@@ -231,7 +231,9 @@ static ssize_t __read_vmcore(char *buffe
list_for_each_entry(m, &vmcore_list, list) {
if (*fpos < m->offset + m->size) {
- tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
+ tsz = (size_t)min_t(unsigned long long,
+ m->offset + m->size - *fpos,
+ buflen);
start = m->paddr + *fpos - m->offset;
tmp = read_from_oldmem(buffer, tsz, &start, userbuf);
if (tmp < 0)
@@ -461,7 +463,8 @@ static int mmap_vmcore(struct file *file
if (start < m->offset + m->size) {
u64 paddr = 0;
- tsz = min_t(size_t, m->offset + m->size - start, size);
+ tsz = (size_t)min_t(unsigned long long,
+ m->offset + m->size - start, size);
paddr = m->paddr + start - m->offset;
if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
paddr >> PAGE_SHIFT, tsz,
next reply other threads:[~2016-03-11 8:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-11 8:42 Dave Young [this message]
2016-03-11 20:27 ` [PATCH V2] proc-vmcore: wrong data type casting fix Andrew Morton
2016-03-12 4:49 ` Dave Young
2016-03-12 12:43 ` Xunlei Pang
2016-03-12 13:59 ` Baoquan He
2016-03-13 6:11 ` Xunlei Pang
2016-03-14 2:41 ` Baoquan He
2016-03-14 3:25 ` HATAYAMA Daisuke
2016-03-14 3:31 ` Dave Young
2016-03-14 3:47 ` Baoquan He
2016-03-14 3:50 ` Baoquan He
2016-03-14 4:36 ` HATAYAMA Daisuke
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=20160311084248.GA9417@dhcp-128-65.nay.redhat.com \
--to=dyoung@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=d.hatayama@jp.fujitsu.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mhuang@redhat.com \
--cc=nasa4836@gmail.com \
--cc=vgoyal@redhat.com \
/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;
as well as URLs for NNTP newsgroup(s).