linux-kernel - Re: [PATCH 20/24] task_diag: Only add VMAs for thread

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 14 Jul 2015 22:01:51 -0400
From:	David Ahern <dsahern@...il.com>
To:	Oleg Nesterov <oleg@...hat.com>, Andrey Vagin <avagin@...nvz.org>
CC:	linux-kernel@...r.kernel.org, linux-api@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Cyrill Gorcunov <gorcunov@...nvz.org>,
	Pavel Emelyanov <xemul@...allels.com>,
	Roger Luethi <rl@...lgate.ch>, Arnd Bergmann <arnd@...db.de>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Pavel Odintsov <pavel.odintsov@...il.com>
Subject: Re: [PATCH 20/24] task_diag: Only add VMAs for thread_group leader

On 7/14/15 1:47 PM, Oleg Nesterov wrote:
> On 07/06, Andrey Vagin wrote:
>>
>> From: David Ahern <dsahern@...il.com>
>>
>> threads of a process share the same VMAs, so when dumping all threads
>> for all processes only push vma data for group leader.
>
> ...
>
>> @@ -492,6 +493,13 @@ static int task_diag_fill(struct task_struct *tsk, struct sk_buff *skb,
>>   	}
>>
>>   	if (show_flags & TASK_DIAG_SHOW_VMA) {
>> +		/* if the request is to dump all threads of all processes
>> +		 * only show VMAs for group leader.
>> +		 */
>> +		if (req->dump_strategy == TASK_DIAG_DUMP_ALL_THREAD &&
>> +		    !thread_group_leader(tsk))
>> +			goto done;
>> +
>
> This doesn't look right, group leader can be a zombie with ->mm == NULL,

Seriously? I'll find some way to track whether VMAs have been dumped for 
a pid.

>
>>   		if (i >= n)
>>   			err = fill_vma(tsk, skb, cb, &progress, show_flags);
>
> so this probably needs something like find_lock_task_mm().

ok.

Thanks for the review,
David

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/