This is a note to let you know that I've just added the patch titled
kobject: fix oops with "input0: bad kobj_uevent_env content in
show_uevent()"
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kobject-fix-oops-with-input0-bad-kobj_uevent_env-content-in-show_uevent.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 60e233a56609fd963c59e99bd75c663d63fa91b6 Mon Sep 17 00:00:00 2001
From: Bjørn Mork <[email protected]>
Date: Sun, 2 Sep 2012 15:41:34 +0200
Subject: kobject: fix oops with "input0: bad kobj_uevent_env content in
show_uevent()"
From: Bjørn Mork <[email protected]>
commit 60e233a56609fd963c59e99bd75c663d63fa91b6 upstream.
Fengguang Wu <[email protected]> writes:
> After the __devinit* removal series, I can still get kernel panic in
> show_uevent(). So there are more sources of bug..
>
> Debug patch:
>
> @@ -343,8 +343,11 @@ static ssize_t show_uevent(struct device
> goto out;
>
> /* copy keys to file */
> - for (i = 0; i < env->envp_idx; i++)
> + dev_err(dev, "uevent %d env[%d]: %s/.../%s\n", env->buflen,
> env->envp_idx, top_kobj->name, dev->kobj.name);
> + for (i = 0; i < env->envp_idx; i++) {
> + printk(KERN_ERR "uevent %d env[%d]: %s\n", (int)count, i,
> env->envp[i]);
> count += sprintf(&buf[count], "%s\n", env->envp[i]);
> + }
>
> Oops message, the env[] is again not properly initilized:
>
> [ 44.068623] input input0: uevent 61 env[805306368]: input0/.../input0
> [ 44.069552] uevent 0 env[0]: (null)
This is a completely different CONFIG_HOTPLUG problem, only
demonstrating another reason why CONFIG_HOTPLUG should go away. I had a
hard time trying to disable it anyway ;-)
The problem this time is lots of code assuming that a call to
add_uevent_var() will guarantee that env->buflen > 0. This is not true
if CONFIG_HOTPLUG is unset. So things like this end up overwriting
env->envp_idx because the array index is -1:
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
len = input_print_modalias(&env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen,
dev, 0);
Don't know what the best action is, given that there seem to be a *lot*
of this around the kernel. This patch "fixes" the problem for me, but I
don't know if it can be considered an appropriate fix.
[ It is the correct fix for now, for 3.7 forcing CONFIG_HOTPLUG to
always be on is the longterm fix, but it's too late for 3.6 and older
kernels to resolve this that way - gregkh ]
Reported-by: Fengguang Wu <[email protected]>
Signed-off-by: Bjørn Mork <[email protected]>
Tested-by: Fengguang Wu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/kobject.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -228,7 +228,7 @@ static inline int kobject_uevent_env(str
static inline __attribute__((format(printf, 2, 3)))
int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
-{ return 0; }
+{ return -ENOMEM; }
static inline int kobject_action_type(const char *buf, size_t count,
enum kobject_action *type)
Patches currently in stable-queue which might be from [email protected] are
queue-3.0/usb-option-replace-zte-k5006-z-entry-with-vendor-class-rule.patch
queue-3.0/kobject-fix-oops-with-input0-bad-kobj_uevent_env-content-in-show_uevent.patch
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