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]
Message-ID: <530f88a1-3aa1-c36f-f487-7e5e33402fb0@I-love.SAKURA.ne.jp>
Date:   Thu, 3 Jan 2019 10:28:45 +0900
From:   Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To:     Qian Cai <cai@....pw>, Mel Gorman <mgorman@...hsingularity.net>,
        Vlastimil Babka <vbabka@...e.cz>
Cc:     syzbot <syzbot+93d94a001cfbce9e60e1@...kaller.appspotmail.com>,
        aarcange@...hat.com, akpm@...ux-foundation.org,
        kirill.shutemov@...ux.intel.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux@...inikbrodowski.net, mhocko@...e.com,
        rientjes@...gle.com, syzkaller-bugs@...glegroups.com,
        xieyisheng1@...wei.com, zhongjiang@...wei.com,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: possible deadlock in __wake_up_common_lock

On 2019/01/03 3:19, Qian Cai wrote:
> On 1/2/19 1:06 PM, Mel Gorman wrote:
> 
>> While I recognise there is no test case available, how often does this
>> trigger in syzbot as it would be nice to have some confirmation any
>> patch is really fixing the problem.
> 
> I think I did manage to trigger this every time running a mmap() workload
> causing swapping and a low-memory situation [1].
> 
> [1]
> https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/oom/oom01.c

wakeup_kswapd() is called because tlb_next_batch() is doing GFP_NOWAIT
allocation. But since tlb_next_batch() can tolerate allocation failure,
does below change in tlb_next_batch() help?

#define GFP_NOWAIT      (__GFP_KSWAPD_RECLAIM)

-	batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+	batch = (void *)__get_free_pages(__GFP_NOWARN, 0);

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ