The patch titled
register_memory/unregister_memory: fix use-after-free and refcounting
has been added to the -mm tree. Its filename is
register_memory-unregister_memory-fix-use-after-free-and-refcounting.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: register_memory/unregister_memory: fix use-after-free and refcounting
From: Badari Pulavarty <pbadari@xxxxxxxxxx>
register_memory()/unregister_memory() never gets called with "root".
unregister_memory() is accessing kobject_name of the object just freed up.
Since no one uses the code, lets take the code out. And also, make
register_memory() static.
Another bug fix - before calling unregister_memory() remove_memory_block()
gets a ref on kobject. unregister_memory() need to drop that ref before
calling sysdev_unregister().
Signed-off-by: Badari Pulavarty <pbadari@xxxxxxxxxx>
Cc: Kay Sievers <kay.sievers@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxx>
Cc: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>
Cc: Andy Whitcroft <apw@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/memory.c | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)
diff -puN drivers/base/memory.c~register_memory-unregister_memory-fix-use-after-free-and-refcounting drivers/base/memory.c
--- a/drivers/base/memory.c~register_memory-unregister_memory-fix-use-after-free-and-refcounting
+++ a/drivers/base/memory.c
@@ -62,8 +62,8 @@ void unregister_memory_notifier(struct n
/*
* register_memory - Setup a sysfs device for a memory block
*/
-int register_memory(struct memory_block *memory, struct mem_section *section,
- struct node *root)
+static
+int register_memory(struct memory_block *memory, struct mem_section *section)
{
int error;
@@ -71,26 +71,18 @@ int register_memory(struct memory_block
memory->sysdev.id = __section_nr(section);
error = sysdev_register(&memory->sysdev);
-
- if (root && !error)
- error = sysfs_create_link(&root->sysdev.kobj,
- &memory->sysdev.kobj,
- kobject_name(&memory->sysdev.kobj));
-
return error;
}
static void
-unregister_memory(struct memory_block *memory, struct mem_section *section,
- struct node *root)
+unregister_memory(struct memory_block *memory, struct mem_section *section)
{
BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
BUG_ON(memory->sysdev.id != __section_nr(section));
+ /* drop the ref. we got in remove_memory_block() */
+ kobject_put(&memory->sysdev.kobj);
sysdev_unregister(&memory->sysdev);
- if (root)
- sysfs_remove_link(&root->sysdev.kobj,
- kobject_name(&memory->sysdev.kobj));
}
/*
@@ -345,7 +337,7 @@ static int add_memory_block(unsigned lon
mutex_init(&mem->state_mutex);
mem->phys_device = phys_device;
- ret = register_memory(mem, section, NULL);
+ ret = register_memory(mem, section);
if (!ret)
ret = mem_create_simple_file(mem, phys_index);
if (!ret)
@@ -396,7 +388,7 @@ int remove_memory_block(unsigned long no
mem_remove_simple_file(mem, phys_index);
mem_remove_simple_file(mem, state);
mem_remove_simple_file(mem, phys_device);
- unregister_memory(mem, section, NULL);
+ unregister_memory(mem, section);
return 0;
}
_
Patches currently in -mm which might be from pbadari@xxxxxxxxxx are
origin.patch
add-remove_memory-for-ppc64-3.patch
enable-hotplug-memory-remove-for-ppc64.patch
register_memory-unregister_memory-fix-use-after-free-and-refcounting.patch
memory-hotplug-add-removable-to-sysfs-to-show-memblock-removability.patch
-
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