Subject: Re: [PATCH] Fix crash due to processing "memory-controller" nodes as "memory"

From: Anton Blanchard <[email-masked]>
Date: Wed, 22 Jul 2015 09:18:44 +1000

Hi,

> > Nice catch! I wonder if we should be checking for device_type
> > "memory". Ben?
> 
> Yes. That's what Linux does.

Ian: I made that change, and slightly modified your commit message.
Look ok?

Anton
--

[PATCH] Fix crash due to processing "memory-controller" nodes as "memory"

If the system has a PCI device with a memory-controller device node,
kexec-lite would spew hundreds of double free warnings and eventually
segfault. This would result in a "kexec load failed" message from
petitboot.

This was due to kexec_memory_map() searching for "memory" nodes, but
actually matching any node that started with "memory", including these
"memory-controller" nodes. This patch changes the search to look for
nodes with a device_type of "memory", which should only match memory
nodes.

An example of a device tree that can trigger this bug is as follows:

{
	pciex@3fffe40000000 {
		...
		pci@0 {
			#address-cells = <0x3>;
			#size-cells = <0x2>;
			...
			memory-controller@0 {
				reg = <0x10000 0x0 0x0 0x0 0x0>;
				...
			};
		};
	};
};

Signed-off-by: Ian Munsie <[email-masked]>
Signed-off-by: Anton Blanchard <[email-masked]>
---
 kexec_memory_map.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kexec_memory_map.c b/kexec_memory_map.c
index fc1b7af..6103590 100644
--- a/kexec_memory_map.c
+++ b/kexec_memory_map.c
@@ -182,7 +182,7 @@ void kexec_memory_map(void *fdt, int reserve_initrd)
 	}
 
 	while (1) {
-		const char *name;
+		const char *type;
 		int len;
 		const fdt64_t *reg;
 
@@ -190,9 +190,9 @@ void kexec_memory_map(void *fdt, int reserve_initrd)
 		if (nodeoffset < 0)
 			break;
 
-		name = fdt_get_name(fdt, nodeoffset, NULL);
+		type = fdt_getprop(fdt, nodeoffset, "device_type", NULL);
 
-		if (!name || strncmp(name, "memory", strlen("memory")))
+		if (!type || strcmp(type, "memory"))
 			continue;
 
 		reg = fdt_getprop(fdt, nodeoffset, "reg", &len);
-- 
2.1.0