Commit e05bd336 authored Jun 29, 2010 by Pavan Naregundi Committed by Linus Torvalds Jun 29, 2010

kexec: fix Oops in crash_shrink_memory()



When crashkernel is not enabled, "echo 0 > /sys/kernel/kexec_crash_size"
OOPSes the kernel in crash_shrink_memory.  This happens when
crash_shrink_memory tries to release the 'crashk_res' resource which are
not reserved.  Also value of "/sys/kernel/kexec_crash_size" shows as 1,
which should be 0.

This patch fixes the OOPS in crash_shrink_memory and shows
"/sys/kernel/kexec_crash_size" as 0 when crash kernel memory is not
reserved.

Signed-off-by: Pavan Naregundi <pavan@linux.vnet.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 482ce512

kernel/kexec.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -1089,8 +1089,9 @@ void crash_kexec(struct pt_regs *regs)

		size_t crash_get_memory_size(void)
		{
		size_t size;
		size_t size = 0;
		mutex_lock(&kexec_mutex);
		if (crashk_res.end != crashk_res.start)
		size = crashk_res.end - crashk_res.start + 1;
		mutex_unlock(&kexec_mutex);
		return size;
		@@ -1134,7 +1135,7 @@ int crash_shrink_memory(unsigned long new_size)

		free_reserved_phys_range(end, crashk_res.end);

		if (start == end)
		if ((start == end) && (crashk_res.parent != NULL))
		release_resource(&crashk_res);
		crashk_res.end = end - 1;

Admin message