Re: 2.6.21-rc7-mm2 crash: Eeek! page_mapcount(page) went negative! (-1)

Tilman Schmidt
2007-05-02T17:33:26Z

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Am 02.05.2007 09:52 schrieb Greg KH:
> Tilman, here's a patch, can you try this on top of your tree that dies?

2.6.21-git3 plus that patch comes up fine.

(Except for a UDP problem I seem to remember I already saw reported
on lkml and which I'll ignore for now in order not to blur the
picture.)

Started to git-bisect mainline now, but that will take some time.
It's more than 800 patches to check and I don't get more than 2-3
iterations per day out of that machine.

HTH
T.

> ---
> drivers/base/core.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -252,7 +252,7 @@ static ssize_t show_uevent(struct device
> struct kobject *top_kobj;
> struct kset *kset;
> char *envp[32];
> - char data[PAGE_SIZE];
> + char *data = NULL;
> char *pos;
> int i;
> size_t count = 0;
> @@ -276,6 +276,10 @@ static ssize_t show_uevent(struct device
> if (!kset->uevent_ops->filter(kset, &dev->kobj))
> goto out;
>
> + data = (char *)get_zeroed_page(GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> /* let the kset specific function add its keys */
> pos = data;
> retval = kset->uevent_ops->uevent(kset, &dev->kobj,
> @@ -290,6 +294,7 @@ static ssize_t show_uevent(struct device
> count += sprintf(pos, "%s\n", envp[i]);
> }
> out:
> + free_page((unsigned long)data);
> return count;
> }
>

--
Tilman Schmidt E-Mail: tilman@imap.cc
Bonn, Germany
- Undetected errors are handled as if no error occurred. (IBM) -

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