From: Aaron Tomlin <atomlin@redhat.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, mhocko@suse.com, willy@infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm/page_alloc: bail out on fatal signal during reclaim/compaction retry attempt
Date: Thu, 20 May 2021 12:42:57 +0100 [thread overview]
Message-ID: <20210520114257.huqhkqsdrhohn3u5@ava.usersys.com> (raw)
In-Reply-To: <9b11dcd8-bc3b-aae9-feb1-43543bf9e22f@suse.cz>
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On Thu 2021-05-20 12:20 +0200, Vlastimil Babka wrote:
> On 5/20/21 6:34 AM, Andrew Morton wrote:
> >
> > What observed problems motivated this change?
> >
> > What were the observed runtime effects of this change?
>
> Yep those details from the previous thread should be included here.
Fair enough.
During kernel crash dump/or vmcore analysis: I discovered in the context of
__alloc_pages_slowpath() the value stored in the no_progress_loops variable
was found to be 31,611,688 i.e. well above MAX_RECLAIM_RETRIES; and a fatal
signal was pending against current.
#6 [ffff00002e78f7c0] do_try_to_free_pages+0xe4 at ffff00001028bd24
#7 [ffff00002e78f840] try_to_free_pages+0xe4 at ffff00001028c0f4
#8 [ffff00002e78f900] __alloc_pages_nodemask+0x500 at ffff0000102cd130
// w28 = *(sp + 148) /* no_progress_loops */
0xffff0000102cd1e0 <__alloc_pages_nodemask+0x5b0>: ldr w0, [sp,#148]
// w0 = w0 + 0x1
0xffff0000102cd1e4 <__alloc_pages_nodemask+0x5b4>: add w0, w0, #0x1
// *(sp + 148) = w0
0xffff0000102cd1e8 <__alloc_pages_nodemask+0x5b8>: str w0, [sp,#148]
// if (w0 >= 0x10)
// goto __alloc_pages_nodemask+0x904
0xffff0000102cd1ec <__alloc_pages_nodemask+0x5bc>: cmp w0, #0x10
0xffff0000102cd1f0 <__alloc_pages_nodemask+0x5c0>: b.gt 0xffff0000102cd534
- The stack pointer was 0xffff00002e78f900
crash> p *(int *)(0xffff00002e78f900+148)
$1 = 31611688
crash> ps 521171
PID PPID CPU TASK ST %MEM VSZ RSS COMM
> 521171 1 36 ffff8080e2128800 RU 0.0 34789440 18624 special
crash> p &((struct task_struct *)0xffff8080e2128800)->signal.shared_pending
$2 = (struct sigpending *) 0xffff80809a416e40
crash> p ((struct sigpending *)0xffff80809a416e40)->signal.sig[0]
$3 = 0x804100
crash> sig -s 0x804100
SIGKILL SIGTERM SIGXCPU
crash> p ((struct sigpending *)0xffff80809a416e40)->signal.sig[0] & 1U << (9 - 1)
$4 = 0x100
Unfortunately, this incident was not reproduced, to date.
Kind regards,
--
Aaron Tomlin
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next prev parent reply other threads:[~2021-05-20 11:43 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 19:23 [PATCH v2] " Aaron Tomlin
2021-05-19 19:32 ` Matthew Wilcox
2021-05-19 19:48 ` Aaron Tomlin
2021-05-19 20:17 ` [PATCH v3] " Aaron Tomlin
2021-05-20 4:34 ` Andrew Morton
2021-05-20 10:20 ` Vlastimil Babka
2021-05-20 11:42 ` Aaron Tomlin [this message]
2021-05-20 11:56 ` Matthew Wilcox
2021-05-20 13:30 ` Aaron Tomlin
2021-05-20 14:29 ` [PATCH v4] " Aaron Tomlin
2021-05-28 12:53 ` Vlastimil Babka
2021-05-31 11:33 ` Michal Hocko
2021-05-31 11:35 ` Vlastimil Babka
2021-05-31 13:21 ` Michal Hocko
2021-05-20 11:09 ` [PATCH v3] " Matthew Wilcox
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