From: Herbert Xu <herbert@gondor.apana.org.au>
To: Edward Adam Davis <eadavis@qq.com>
Cc: davem@davemloft.net, 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: Sat, 2 Dec 2023 07:38:58 +0800 [thread overview]
Message-ID: <ZWpukgSDlA6UFR6e@gondor.apana.org.au> (raw)
In-Reply-To: <tencent_B2D2C5864C49BDAEE0AEC1CC9627E3C6CF06@qq.com>
On Fri, Dec 01, 2023 at 08:34:12PM +0800, Edward Adam Davis wrote:
>
> 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.
Oh I see what's going on. The reproducer is mapping /dev/hwrng, so
the write to user-space is then triggering another read which then
dead-locks.
Let me think about this.
Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2023-12-01 23:39 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
2023-12-01 23:38 ` Herbert Xu [this message]
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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