From d9345bc5bf8063ce433c0152893f93000fb0ddfb Mon Sep 17 00:00:00 2001 From: Jo-Philipp Wich Date: Mon, 15 Aug 2016 12:14:50 +0200 Subject: [PATCH] kernel: fix crashlog on x86/64 The bootmem area reserved for crashlog might be smaller than CRASHLOG_OFFSET bytes, leading to an integer underflow when calculating the memory address in crashlog_set_addr() which subsequently causes the kernel to crash when attempting to vmap() the crashlog pages. Change the logic to only consider the offset when the size of the used memory area is sufficient. Signed-off-by: Jo-Philipp Wich --- target/linux/generic/patches-4.4/930-crashlog.patch | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/target/linux/generic/patches-4.4/930-crashlog.patch b/target/linux/generic/patches-4.4/930-crashlog.patch index bb97c90196..fdc80d750a 100644 --- a/target/linux/generic/patches-4.4/930-crashlog.patch +++ b/target/linux/generic/patches-4.4/930-crashlog.patch @@ -43,7 +43,7 @@ --- /dev/null +++ b/kernel/crashlog.c -@@ -0,0 +1,209 @@ +@@ -0,0 +1,213 @@ +/* + * Crash information logger + * Copyright (C) 2010 Felix Fietkau @@ -117,7 +117,11 @@ + if (addr + size > limit) + size = limit - addr; + -+ crashlog_addr = addr + size - CRASHLOG_OFFSET; ++ crashlog_addr = addr; ++ ++ if (addr + size > CRASHLOG_OFFSET) ++ crashlog_addr += size - CRASHLOG_OFFSET; ++ + return true; +} +