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
to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 60e233a56609fd963c59e99bd75c663d63fa91b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <[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()"
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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]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/kobject.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index fc615a9..1e57449 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -224,7 +224,7 @@ static inline int kobject_uevent_env(struct kobject *kobj,
static inline __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)
--
1.7.12.176.g3fc0e4c
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