From: Michal Hocko <mhocko@kernel.org>
To: Qian Cai <cai@lca.pw>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
davem@davemloft.net, netdev@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] net/skbuff: silence warnings under memory pressure
Date: Wed, 4 Sep 2019 08:15:01 +0200 [thread overview]
Message-ID: <20190904061501.GB3838@dhcp22.suse.cz> (raw)
In-Reply-To: <1567546948.5576.68.camel@lca.pw>
Cc printk maintainers
On Tue 03-09-19 17:42:28, Qian Cai wrote:
> > > I suppose what happens is those skb_build() allocations are from softirq,
> > > and
> > > once one of them failed, it calls printk() which generates more interrupts.
> > > Hence, the infinite loop.
> >
> > Please elaborate more.
> >
>
> If you look at the original report, the failed allocation dump_stack() is,
>
> <IRQ>
> warn_alloc.cold.43+0x8a/0x148
> __alloc_pages_nodemask+0x1a5c/0x1bb0
> alloc_pages_current+0x9c/0x110
> allocate_slab+0x34a/0x11f0
> new_slab+0x46/0x70
> ___slab_alloc+0x604/0x950
> __slab_alloc+0x12/0x20
> kmem_cache_alloc+0x32a/0x400
> __build_skb+0x23/0x60
> build_skb+0x1a/0xb0
> igb_clean_rx_irq+0xafc/0x1010 [igb]
> igb_poll+0x4bb/0xe30 [igb]
> net_rx_action+0x244/0x7a0
> __do_softirq+0x1a0/0x60a
> irq_exit+0xb5/0xd0
> do_IRQ+0x81/0x170
> common_interrupt+0xf/0xf
> </IRQ>
>
> Since it has no __GFP_NOWARN to begin with, it will call,
>
> printk
> vprintk_default
> vprintk_emit
> wake_up_klogd
> irq_work_queue
> __irq_work_queue_local
> arch_irq_work_raise
> apic->send_IPI_self(IRQ_WORK_VECTOR)
> smp_irq_work_interrupt
> exiting_irq
> irq_exit
>
> and end up processing pending net_rx_action softirqs again which are plenty due
> to connected via ssh etc.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-09-04 6:15 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-30 14:57 [PATCH] net/skbuff: silence warnings under memory pressure Qian Cai
2019-08-30 15:11 ` Eric Dumazet
2019-08-30 15:25 ` Qian Cai
2019-08-30 16:15 ` Eric Dumazet
2019-08-30 18:06 ` Qian Cai
2019-09-03 13:22 ` Michal Hocko
2019-09-03 15:42 ` Qian Cai
2019-09-03 18:53 ` Michal Hocko
2019-09-03 21:42 ` Qian Cai
2019-09-04 6:15 ` Michal Hocko [this message]
2019-09-04 6:41 ` Sergey Senozhatsky
2019-09-04 6:54 ` Michal Hocko
2019-09-04 7:19 ` Sergey Senozhatsky
2019-09-04 7:43 ` Sergey Senozhatsky
2019-09-04 12:14 ` Qian Cai
2019-09-04 14:48 ` Sergey Senozhatsky
2019-09-04 15:07 ` Qian Cai
2019-09-04 20:42 ` Qian Cai
2019-09-05 8:32 ` Eric Dumazet
2019-09-05 14:09 ` Qian Cai
2019-09-05 15:06 ` Eric Dumazet
2019-09-05 15:14 ` Eric Dumazet
2019-09-05 11:32 ` Sergey Senozhatsky
2019-09-05 16:03 ` Qian Cai
2019-09-05 17:14 ` Steven Rostedt
2019-09-06 2:50 ` Sergey Senozhatsky
2019-09-06 4:32 ` Sergey Senozhatsky
2019-09-06 21:17 ` Qian Cai
2019-09-05 17:23 ` Steven Rostedt
2019-09-06 3:39 ` Sergey Senozhatsky
2019-09-06 15:32 ` Petr Mladek
2019-09-09 1:10 ` Sergey Senozhatsky
2019-09-06 14:55 ` Petr Mladek
2019-09-06 19:51 ` Sergey Senozhatsky
2019-11-14 17:12 ` Qian Cai
2019-11-18 15:27 ` Petr Mladek
2019-11-19 0:41 ` Sergey Senozhatsky
2019-11-19 9:41 ` Petr Mladek
2019-11-19 15:58 ` Qian Cai
2019-11-20 1:30 ` Sergey Senozhatsky
2019-11-20 16:13 ` Petr Mladek
2019-11-21 1:05 ` Sergey Senozhatsky
2019-11-21 9:15 ` Petr Mladek
2019-09-04 7:00 ` Sergey Senozhatsky
2019-09-04 8:25 ` Michal Hocko
2019-09-04 11:59 ` Qian Cai
2019-09-04 12:07 ` Michal Hocko
2019-09-04 12:28 ` Qian Cai
2019-09-07 11:00 ` Tetsuo Handa
2019-09-04 6:15 ` Michal Hocko
2019-09-02 14:24 ` Vlastimil Babka
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