linux-kernel - Re: kexec load failure introduced by "x86, memblock: Replace e820_/_early string with memblock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 26 Sep 2010 23:31:09 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	caiqian@...hat.com
CC:	kexec <kexec@...ts.infradead.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: kexec load failure introduced by "x86, memblock: Replace e820_/_early
 string with memblock_"

Please check this one on top of tip or next.

Thanks

Yinghai

[PATCH] x86, memblock: Fix crashkernel allocation

Cai Qian found that crashkernel is broken with x86 memblock changes
1. crashkernel=128M@32M always reported that range is used, even first kernel is small
   no one use that range
2. always get following report when using "kexec -p"
	Could not find a free area of memory of a000 bytes...
	locate_hole failed

The root cause is that generic memblock_find_in_range() will try to get range from top_down.
But crashkernel do need from low and specified range.

Let's limit the target range with rash_base + crash_size to make sure that
We get range from bottom.

Reported-and-Bisected-by: CAI Qian <caiqian@...hat.com>
Signed-off-by: Yinghai Lu <yinghai@...nel.org>

---
 arch/x86/kernel/setup.c |   19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -516,19 +516,28 @@ static void __init reserve_crashkernel(v
 
 	/* 0 means: find the address automatically */
 	if (crash_base <= 0) {
+		unsigned long long start = 0;
 		const unsigned long long alignment = 16<<20;	/* 16M */
 
-		crash_base = memblock_find_in_range(alignment, ULONG_MAX, crash_size,
-				 alignment);
-		if (crash_base == MEMBLOCK_ERROR) {
+		crash_base = alignment;
+		while (crash_base < 0xffffffff) {
+			start = memblock_find_in_range(crash_base,
+				crash_base + crash_size, crash_size, alignment);
+
+			if (start == crash_base)
+				break;
+
+			crash_base += alignment;
+		}
+		if (start != crash_base) {
 			pr_info("crashkernel reservation failed - No suitable area found.\n");
 			return;
 		}
 	} else {
 		unsigned long long start;
 
-		start = memblock_find_in_range(crash_base, ULONG_MAX, crash_size,
-				 1<<20);
+		start = memblock_find_in_range(crash_base,
+				 crash_base + crash_size, crash_size, 1<<20);
 		if (start != crash_base) {
 			pr_info("crashkernel reservation failed - memory is in use.\n");
 			return;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/