From fe2d48b805d01e14ddb8144de01de43171eb516f Mon Sep 17 00:00:00 2001 From: Jiri Bohac Date: Fri, 16 Jun 2017 18:16:02 +0200 Subject: [PATCH] x86/debug: Extend the lower bound of crash kernel low reservations The following change in 2013: 0212f9159694 ("x86: Add Crash kernel low reservation") ... introduced reserve_crashkernel_low(). This function is used to reserve crash kernel memory either if crashkernel=size,low is given on the command line or if the region reserved by reserve_crashkernel is entirely above 4G. reserve_crashkernel_low() tries to find a block of 'low_size' bytes. But there seems to be no good reason to restrict the lower bound of the range to 'low_size'. Make memblock_find_in_range() search from the start of memory. Signed-off-by: Jiri Bohac Cc: Eric Biederman Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yinghai Lu Link: http://lkml.kernel.org/r/20170616161602.2r7birrf2y3ylv6v@dwarf.suse.cz Signed-off-by: Ingo Molnar --- arch/x86/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 0b4d3c686b1e..848d0489ad00 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -503,7 +503,7 @@ static int __init reserve_crashkernel_low(void) return 0; } - low_base = memblock_find_in_range(low_size, 1ULL << 32, low_size, CRASH_ALIGN); + low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN); if (!low_base) { pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n", (unsigned long)(low_size >> 20));