diff options
| author | Michael Holzheu <holzheu@linux.vnet.ibm.com> | 2012-01-12 17:20:15 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-12 20:13:11 -0800 |
| commit | bec013c40bc89671d8d457944fdf7d2b8e79d651 (patch) | |
| tree | f48220571120805a319f0df876c1cc465586978e /kernel | |
| parent | 6480e5a0923756b500634d9777ec4189492fbbfe (diff) | |
| download | linux-bec013c40bc89671d8d457944fdf7d2b8e79d651.tar.bz2 | |
kdump: crashk_res init check for /sys/kernel/kexec_crash_size
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.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kexec.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/kexec.c b/kernel/kexec.c index 60bf181b3eae..7b0886786701 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1129,6 +1129,7 @@ int crash_shrink_memory(unsigned long new_size) { int ret = 0; unsigned long start, end; + unsigned long old_size; struct resource *ram_res; mutex_lock(&kexec_mutex); @@ -1139,11 +1140,9 @@ int crash_shrink_memory(unsigned long new_size) } 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; } |