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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Qian Cai <cai@redhat.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	linux-kernel@vger.kernel.org, virtio-fs@redhat.com,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [Virtio-fs] Unbreakable loop in fuse_fill_write_pages()
Date: Wed, 14 Oct 2020 09:26:21 +0100	[thread overview]
Message-ID: <20201014082621.GA2996@work-vm> (raw)
In-Reply-To: <d14f6a08b4ada85289e70cbb34726fd084ccac05.camel@redhat.com>

* Qian Cai (cai@redhat.com) wrote:
> On Tue, 2020-10-13 at 14:58 -0400, Vivek Goyal wrote:
> 
> > I am wondering if virtiofsd still alive and responding to requests? I
> > see another task which is blocked on getdents() for more than 120s.
> > 
> > [10580.142571][  T348] INFO: task trinity-c36:254165 blocked for more than 123
> > +seconds.
> > [10580.143924][  T348]       Tainted: G           O	 5.9.0-next-20201013+ #2
> > [10580.145158][  T348] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> > +disables this message.
> > [10580.146636][  T348] task:trinity-c36     state:D stack:26704 pid:254165
> > ppid:
> > +87180 flags:0x00000004
> > [10580.148260][  T348] Call Trace:
> > [10580.148789][  T348]  __schedule+0x71d/0x1b50
> > [10580.149532][  T348]  ? __sched_text_start+0x8/0x8
> > [10580.150343][  T348]  schedule+0xbf/0x270
> > [10580.151044][  T348]  schedule_preempt_disabled+0xc/0x20
> > [10580.152006][  T348]  __mutex_lock+0x9f1/0x1360
> > [10580.152777][  T348]  ? __fdget_pos+0x9c/0xb0
> > [10580.153484][  T348]  ? mutex_lock_io_nested+0x1240/0x1240
> > [10580.154432][  T348]  ? find_held_lock+0x33/0x1c0
> > [10580.155220][  T348]  ? __fdget_pos+0x9c/0xb0
> > [10580.155934][  T348]  __fdget_pos+0x9c/0xb0
> > [10580.156660][  T348]  __x64_sys_getdents+0xff/0x230
> > 
> > May be virtiofsd crashed and hence no requests are completing leading
> > to a hard lockup?
> Virtiofsd is still working. Once this happened, I manually create a file on the
> guest (in virtiofs) and then I can see the content of it from the host.

If the virtiofsd is still running, attach gdb to it and get a full bt;

gdb --pid  whatever

(gdb) t a a bt full

that should show if it's stuck in one particular place.

Dave


> _______________________________________________
> Virtio-fs mailing list
> Virtio-fs@redhat.com
> https://www.redhat.com/mailman/listinfo/virtio-fs
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK


WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Qian Cai <cai@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	linux-kernel@vger.kernel.org, virtio-fs@redhat.com,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [Virtio-fs] Unbreakable loop in fuse_fill_write_pages()
Date: Wed, 14 Oct 2020 09:26:21 +0100	[thread overview]
Message-ID: <20201014082621.GA2996@work-vm> (raw)
In-Reply-To: <d14f6a08b4ada85289e70cbb34726fd084ccac05.camel@redhat.com>

* Qian Cai (cai@redhat.com) wrote:
> On Tue, 2020-10-13 at 14:58 -0400, Vivek Goyal wrote:
> 
> > I am wondering if virtiofsd still alive and responding to requests? I
> > see another task which is blocked on getdents() for more than 120s.
> > 
> > [10580.142571][  T348] INFO: task trinity-c36:254165 blocked for more than 123
> > +seconds.
> > [10580.143924][  T348]       Tainted: G           O	 5.9.0-next-20201013+ #2
> > [10580.145158][  T348] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> > +disables this message.
> > [10580.146636][  T348] task:trinity-c36     state:D stack:26704 pid:254165
> > ppid:
> > +87180 flags:0x00000004
> > [10580.148260][  T348] Call Trace:
> > [10580.148789][  T348]  __schedule+0x71d/0x1b50
> > [10580.149532][  T348]  ? __sched_text_start+0x8/0x8
> > [10580.150343][  T348]  schedule+0xbf/0x270
> > [10580.151044][  T348]  schedule_preempt_disabled+0xc/0x20
> > [10580.152006][  T348]  __mutex_lock+0x9f1/0x1360
> > [10580.152777][  T348]  ? __fdget_pos+0x9c/0xb0
> > [10580.153484][  T348]  ? mutex_lock_io_nested+0x1240/0x1240
> > [10580.154432][  T348]  ? find_held_lock+0x33/0x1c0
> > [10580.155220][  T348]  ? __fdget_pos+0x9c/0xb0
> > [10580.155934][  T348]  __fdget_pos+0x9c/0xb0
> > [10580.156660][  T348]  __x64_sys_getdents+0xff/0x230
> > 
> > May be virtiofsd crashed and hence no requests are completing leading
> > to a hard lockup?
> Virtiofsd is still working. Once this happened, I manually create a file on the
> guest (in virtiofs) and then I can see the content of it from the host.

If the virtiofsd is still running, attach gdb to it and get a full bt;

gdb --pid  whatever

(gdb) t a a bt full

that should show if it's stuck in one particular place.

Dave


> _______________________________________________
> Virtio-fs mailing list
> Virtio-fs@redhat.com
> https://www.redhat.com/mailman/listinfo/virtio-fs
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK


  parent reply	other threads:[~2020-10-14  8:26 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-13 17:11 [Virtio-fs] Unbreakable loop in fuse_fill_write_pages() Qian Cai
2020-10-13 17:11 ` Qian Cai
2020-10-13 18:40 ` [Virtio-fs] " Vivek Goyal
2020-10-13 18:40   ` Vivek Goyal
2020-10-13 18:58   ` [Virtio-fs] " Vivek Goyal
2020-10-13 18:58     ` Vivek Goyal
2020-10-13 19:12     ` [Virtio-fs] " Qian Cai
2020-10-13 19:12       ` Qian Cai
2020-10-13 19:20       ` [Virtio-fs] " Harry G. Coin
2020-10-13 19:53     ` Qian Cai
2020-10-13 19:53       ` Qian Cai
2020-10-13 19:57       ` [Virtio-fs] " Vivek Goyal
2020-10-13 19:57         ` Vivek Goyal
2020-10-13 20:10         ` [Virtio-fs] " Qian Cai
2020-10-13 20:10           ` Qian Cai
2020-10-14  8:26       ` Dr. David Alan Gilbert [this message]
2020-10-14  8:26         ` [Virtio-fs] " Dr. David Alan Gilbert
2020-10-15 13:18   ` Qian Cai
2020-10-15 13:18     ` Qian Cai

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