Messages in this thread Patch in this message | | | Date | Wed, 23 Nov 2011 21:34:33 +0800 | From | Dave Young <> | Subject | Re: [PATCH v2] kdump: crashk_res init check for /sys/kernel/kexec_crash_size |
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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
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