Re: AMD-IOMMU and problem with __init(data)?

[Alexander Holler <holler@ahsoftware.de>]

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Am 23.09.2015 um 17:50 schrieb Alexander Holler:
> Am 23.09.2015 um 13:43 schrieb Joerg Roedel:
>>> If it's necessary, I could try put together a small patch which
>>> kills a system (reproducible here).
>>
>> That would help too, please also send me your .config and I'll try to
>> reproduce the issue here.
>
> Will do. Later.

Done. Patch(es) and config attached. Note, while reducing the patch, 
I've noted that when I change


struct _annotated_initcall {
	initcall_t initcall;
	unsigned driver_id;
	unsigned *dependencies;
	struct device_driver *driver;
};

to

struct _annotated_initcall {
	initcall_t initcall;
	unsigned driver_id;
};

it does not crash. That's what the second patch does. So in order to 
crash a system, just use patch 0001.

Regards,

Alexander Holler

[-- Attachment #2: 0001-CRASH-on-AMD-with-CONFIG_AMD_IOMMU.patch --]
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>From d94e5568925d7cb8a3fc628606e8fcf1374ea177 Mon Sep 17 00:00:00 2001
From: Alexander Holler <holler@ahsoftware.de>
Date: Wed, 23 Sep 2015 19:43:51 +0200
Subject: [PATCH 1/2] CRASH on AMD with CONFIG_AMD_IOMMU

---
 include/asm-generic/vmlinux.lds.h |  6 ++++++
 init/main.c                       | 30 +++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 8bd374d..13f9189 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -660,6 +660,11 @@
 		INIT_CALLS_LEVEL(7)					\
 		VMLINUX_SYMBOL(__initcall_end) = .;
 
+#define ANNOTATED_INITCALLS						\
+		VMLINUX_SYMBOL(__annotated_initcall_start) = .;		\
+		*(.annotated_initcall.init)				\
+		VMLINUX_SYMBOL(__annotated_initcall_end) = .;
+
 #define CON_INITCALL							\
 		VMLINUX_SYMBOL(__con_initcall_start) = .;		\
 		*(.con_initcall.init)					\
@@ -816,6 +821,7 @@
 		INIT_DATA						\
 		INIT_SETUP(initsetup_align)				\
 		INIT_CALLS						\
+		ANNOTATED_INITCALLS					\
 		CON_INITCALL						\
 		SECURITY_INITCALL					\
 		INIT_RAM_FS						\
diff --git a/init/main.c b/init/main.c
index 5650655..1498f9b 100644
--- a/init/main.c
+++ b/init/main.c
@@ -859,12 +859,40 @@ static void __init do_initcall_level(int level)
 		do_one_initcall(*fn);
 }
 
+struct _annotated_initcall {
+	initcall_t initcall;
+	unsigned driver_id;
+	unsigned *dependencies;
+	struct device_driver *driver;
+};
+extern struct _annotated_initcall __annotated_initcall_start[];
+
+#define annotated_initcall(fn, id) \
+	static struct _annotated_initcall __annotated_initcall_##fn __used \
+	__attribute__((__section__(".annotated_initcall.init"))) = \
+							{ .initcall = fn, .driver_id = id }
+
+
+static int __init foo(void)
+{
+	return 0;
+}
+
+annotated_initcall(foo, 23);
+
 static void __init do_initcalls(void)
 {
 	int level;
+	struct _annotated_initcall *ac;
 
-	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
+	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 3; level++)
 		do_initcall_level(level);
+
+	ac = __annotated_initcall_start;
+	pr_info("ac %p ID %u\n", ac, ac->driver_id);
+	BUG_ON(ac->driver_id != 23);
+	do_initcall_level(level++);
+	do_initcall_level(level);
 }
 
 /*
-- 
2.1.0


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>From 17c9b286710931947c63ef49bba69f679ecdc400 Mon Sep 17 00:00:00 2001
From: Alexander Holler <holler@ahsoftware.de>
Date: Wed, 23 Sep 2015 20:39:28 +0200
Subject: [PATCH 2/2] NO crash

---
 init/main.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/init/main.c b/init/main.c
index 1498f9b..4c1f041 100644
--- a/init/main.c
+++ b/init/main.c
@@ -862,8 +862,6 @@ static void __init do_initcall_level(int level)
 struct _annotated_initcall {
 	initcall_t initcall;
 	unsigned driver_id;
-	unsigned *dependencies;
-	struct device_driver *driver;
 };
 extern struct _annotated_initcall __annotated_initcall_start[];
 
-- 
2.1.0


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