From: Edward Adam Davis <eadavis@qq.com>
To: herbert@gondor.apana.org.au
Cc: davem@davemloft.net, eadavis@qq.com,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
olivia@selenic.com,
syzbot+c52ab18308964d248092@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH] hwrng: core - fix task hung in hwrng_fillfn
Date: Fri, 1 Dec 2023 20:34:12 +0800 [thread overview]
Message-ID: <tencent_B2D2C5864C49BDAEE0AEC1CC9627E3C6CF06@qq.com> (raw)
In-Reply-To: <ZWnGV39HJr9uUB2/@gondor.apana.org.au>
On Fri, 1 Dec 2023 19:41:11 +0800, Herbert Xu wrote:
> >
> > Reduce the scope of critical zone protection.
> > The original critical zone contains a too large range, especially like
> > copy_to_user() should not be included in the critical zone.
>
> Which part in particular is taking 143 seconds? The buffer is
> only 128 bytes long. Why is a 128-byte copy taking 143 seconds,
> even with a page fault?
According to splat, after a page fault occurred, the attempt to retrieve
rcu_read_lock() failed, resulting in a timeout of 143s. This is my speculation.
Edward
next prev parent reply other threads:[~2023-12-01 12:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
2023-11-26 7:07 ` [PATCH] hwrng: core - fix " Edward Adam Davis
2023-12-01 9:56 ` Herbert Xu
2023-12-01 11:37 ` Edward Adam Davis
2023-12-01 11:41 ` Herbert Xu
2023-12-01 12:34 ` Edward Adam Davis [this message]
2023-12-01 23:38 ` Herbert Xu
2023-12-02 1:01 ` [PATCH] hwrng: core - Fix page fault dead lock on mmap-ed hwrng Herbert Xu
2023-12-12 14:03 ` PrasannaKumar Muralidharan
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