linux-kernel - Re: [PATCH -next] livepatch: Fix missing unlock on error in klp_enable

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Date:   Mon, 3 Jan 2022 11:49:14 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     David Vernet <void@...ifault.com>
Cc:     Yang Yingliang <yangyingliang@...wei.com>,
        linux-kernel@...r.kernel.org, live-patching@...r.kernel.org,
        jpoimboe@...hat.com, jikos@...nel.org, mbenes@...e.cz
Subject: Re: [PATCH -next] livepatch: Fix missing unlock on error in
 klp_enable_patch()

On Mon 2021-12-27 08:31:45, David Vernet wrote:
> Yang Yingliang <yangyingliang@...wei.com> wrote on Sat [2021-Dec-25 10:51:15 +0800]:
> > Add missing unlock when try_module_get() fails in klp_enable_patch().
> > 
> > Fixes: bf01c2975925 ("livepatch: Fix kobject refcount bug on klp_init_patch_early failure path")
> > Reported-by: Hulk Robot <hulkci@...wei.com>
> > Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
> > ---
> >  kernel/livepatch/core.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> > index 23cf444091a8..01bfab7fe7c0 100644
> > --- a/kernel/livepatch/core.c
> > +++ b/kernel/livepatch/core.c
> > @@ -1047,8 +1047,10 @@ int klp_enable_patch(struct klp_patch *patch)
> >  		return -EINVAL;
> >  	}
> >  
> > -	if (!try_module_get(patch->mod))
> > +	if (!try_module_get(patch->mod)) {
> > +		mutex_unlock(&klp_mutex);
> >  		return -ENODEV;
> > +	}
> >  
> >  	klp_init_patch_early(patch);
> >  
> > -- 
> > 2.25.1
> > 
> 
> Apologies for the silly oversight. Thank you for the fix.

And nobody caught it. I think that it was partly caused by
a pre-holiday loss of concentration :-/

> Acked-by: David Vernet <void@...ifault.com>

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr