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Date:   Mon, 11 Jan 2021 15:21:31 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     Xiaoming Ni <nixiaoming@huawei.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        linux-kernel@vger.kernel.org, mcgrof@kernel.org,
        yzaikin@google.com, adobriyan@gmail.com,
        linux-fsdevel@vger.kernel.org, vbabka@suse.cz, wangle6@huawei.com
Subject: Re: [PATCH v2] proc_sysctl: fix oops caused by incorrect command
 parameters.
Message-ID: <20210111142131.GA22493@dhcp22.suse.cz>
References: <20210108023339.55917-1-nixiaoming@huawei.com>
 <20210108092145.GX13207@dhcp22.suse.cz>
 <829bbba0-d3bb-a114-af81-df7390082958@huawei.com>
 <20210108114718.GA13207@dhcp22.suse.cz>
 <202101081152.0CB22390@keescook>
 <20210108201025.GA17019@dhcp22.suse.cz>
 <20210108175008.da3c60a6e402f5f1ddab2a65@linux-foundation.org>
 <bc098af4-c0cd-212e-d09d-46d617d0acab@huawei.com>
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On Mon 11-01-21 11:48:19, Xiaoming Ni wrote:
[...]
> patch3:
> 	+++ b/fs/proc/proc_sysctl.c
> 	@@ -1770,6 +1770,9 @@ static int process_sysctl_arg(char *param, char *val,
> 							return 0;
> 			}
> 
> 	+       if (!val)
> 	+               return -EINVAL;
> 	+
> 			/*
> 			 * To set sysctl options, we use a temporary mount of proc, look up the
> 			 * respective sys/ file and write to it. To avoid mounting it when no
> 
> sysctl log for patch3:
> 	Setting sysctl args: `' invalid for parameter `hung_task_panic'
[...]
> When process_sysctl_arg() is called, the param parameter may not be the
> sysctl parameter.
> 
> Patch3 or patch4, which is better?

Patch3

-- 
Michal Hocko
SUSE Labs