From: Dave Young <dyoung@redhat.com>
To: holzheu@linux.vnet.ibm.com
Cc: akpm@linux-foundation.org, heiko.carstens@de.ibm.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
Simon Horman <horms@verge.net.au>,
"Eric W. Biederman" <ebiederm@xmission.com>,
schwidefsky@de.ibm.com, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v2] kdump: crashk_res init check for /sys/kernel/kexec_crash_size
Date: Wed, 23 Nov 2011 21:34:33 +0800 [thread overview]
Message-ID: <4ECCF669.6080007@redhat.com> (raw)
In-Reply-To: <1322054283.10119.11.camel@br98xy6r>
On 11/23/2011 09:18 PM, Michael Holzheu wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
>
> Currently it is possible to set the crash_size via the sysfs
> /sys/kernel/kexec_crash_size even if no crash kernel memory has
> been defined with the "crashkernel" parameter. In this case
> "crashk_res" is not initialized and crashk_res.start = crashk_res.end = 0.
> Unfortunately resource_size(&crashk_res) returns 1 in this case.
> This breaks the s390 implementation of crash_(un)map_reserved_pages().
>
> To fix the problem the correct "old_size" is now calculated in
> crash_shrink_memory(). "old_size is set to "0" if crashk_res is
> not initialized. With this change crash_shrink_memory() will do nothing,
> when "crashk_res" is not initialized. It will return "0" for
> "echo 0 > /sys/kernel/kexec_crash_size" and -EINVAL for
> "echo [not zero] > /sys/kernel/kexec_crash_size".
>
> In addition to that this patch also simplifies the "ret = -EINVAL"
> vs. "ret = 0" logic as suggested by Simon Horman.
>
> Cc: Simon Horman <horms@verge.net.au>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> ---
> kernel/kexec.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -1131,7 +1131,7 @@ void __weak crash_free_reserved_phys_ran
> int crash_shrink_memory(unsigned long new_size)
> {
> int ret = 0;
> - unsigned long start, end;
> + unsigned long start, end, old_size;
Sorry for jump in a little late, instead of introduce a new variable,
why not add something like:
if (!end)
return -EINVAL;
>
> mutex_lock(&kexec_mutex);
>
> @@ -1141,11 +1141,9 @@ int crash_shrink_memory(unsigned long ne
> }
> start = crashk_res.start;
> end = crashk_res.end;
> -
> - if (new_size >= end - start + 1) {
> - ret = -EINVAL;
> - if (new_size == end - start + 1)
> - ret = 0;
> + old_size = (end == 0) ? 0 : end - start + 1;
> + if (new_size >= old_size) {
> + ret = (new_size == old_size) ? 0 : -EINVAL;
> goto unlock;
> }
>
>
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
--
Thanks
Dave
next prev parent reply other threads:[~2011-11-23 13:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-23 10:11 [PATCH] kdump: crashk_res init check for /sys/kernel/kexec_crash_size Michael Holzheu
2011-11-23 10:22 ` Simon Horman
2011-11-23 13:18 ` [PATCH v2] " Michael Holzheu
2011-11-23 13:34 ` Dave Young [this message]
2011-11-23 13:46 ` Michael Holzheu
2011-11-23 14:03 ` Dave Young
2011-11-23 15:01 ` Cong Wang
2011-11-24 0:10 ` 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=4ECCF669.6080007@redhat.com \
--to=dyoung@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=heiko.carstens@de.ibm.com \
--cc=holzheu@linux.vnet.ibm.com \
--cc=horms@verge.net.au \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=schwidefsky@de.ibm.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).