linux-kernel - [PATCH v2 2/2] kexec: Consider crashk_low_res in sanity_check_segment

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Date:	Wed, 17 Aug 2016 09:50:57 +0800
From:	Xunlei Pang <xlpang@...hat.com>
To:	linux-kernel@...r.kernel.org, kexec@...ts.infradead.org
Cc:	akpm@...ux-foundation.org, ebiederm@...ssion.com,
	Vivek Goyal <vgoyal@...hat.com>,
	Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
	Xunlei Pang <xlpang@...hat.com>
Subject: [PATCH v2 2/2] kexec: Consider crashk_low_res in sanity_check_segment_list()

We have crashk_res only in most cases, but sometimes we have
crashk_low_res.

For example, on 64-bit x86 systems, when "crashkernel=32M,high"
combined with "crashkernel=128M,low" is used, so some segments
may have the chance to be loaded into crashk_low_res area. We
can't fail it as a memory violation in these cases.

Thus, we add the case to regard the segment as valid if it is
within crashk_low_res.

Signed-off-by: Xunlei Pang <xlpang@...hat.com>
---
 kernel/kexec_core.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 707d18e..9012a60 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -248,9 +248,14 @@ int sanity_check_segment_list(struct kimage *image)
 			mstart = image->segment[i].mem;
 			mend = mstart + image->segment[i].memsz - 1;
 			/* Ensure we are within the crash kernel limits */
-			if ((mstart < phys_to_boot_phys(crashk_res.start)) ||
-			    (mend > phys_to_boot_phys(crashk_res.end)))
-				return -EADDRNOTAVAIL;
+			if ((mstart >= phys_to_boot_phys(crashk_res.start)) &&
+			    (mend <= phys_to_boot_phys(crashk_res.end)))
+				continue;
+			if ((mstart >= phys_to_boot_phys(crashk_low_res.start)) &&
+			    (mend <= phys_to_boot_phys(crashk_low_res.end)))
+				continue;
+
+			return -EADDRNOTAVAIL;
 		}
 	}
 
-- 
1.8.3.1