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SubjectRe: [v4 PATCH 1/1] init: fix race between rootfs mount and firmware loading
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Thanks, Oleg, for the review.

--
Roman

On Sat, Sep 20, 2014 at 4:45 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 09/19, Roman Pen wrote:
>>
>> +void wait_for_rootfs(void)
>> +{
>> + /* Here we try to protect from a few things:
>> + * 1. Avoid waiting for ourselves, when init thread has not
>> + * mounted rootfs yet.
>> + * 2. Avoid warning if call chain was initiated from userspace
>> + * /sbin/init. For example when /sbin/init loads the driver,
>> + * which, in turn, wants to access rootfs (e.g. firmware loading),
>> + * thus it has to be sure, that rootfs has been successfully
>> + * mounted.
>> + */
>> + if (rootfs_mounted || WARN_ON(is_global_init(current)))
>> + return;
>> + else
>> + wait_event(rootfs_waitq, rootfs_mounted);
>> +}
>
> Well, in this case __wait_event() makes more sense, we already checked
> rootfs_mounted, but this is minor.
>
> Reviewed-by: Oleg Nesterov <oleg@redhat.com>
>
>
> But I hope that Greg can take a look too. I do not understand the problem
> space enough, so I am not sure this is the "right" fix. Say, perhaps we
> should change the drivers which abuse request_firmware(), or do something
> else.
>
> Oleg.
>


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