From: Eric Biggers <ebiggers@kernel.org>
To: Siddh Raman Pant <code@siddh.me>
Cc: syzbot <syzbot+c70d87ac1d001f29a058@syzkaller.appspotmail.com>,
hdanton <hdanton@sina.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: [syzbot] KASAN: use-after-free Read in post_one_notification
Date: Tue, 2 Aug 2022 21:09:34 -0700 [thread overview]
Message-ID: <Yun0/rDv4ptBl65S@sol.localdomain> (raw)
In-Reply-To: <18261e01068.4a2910f2403165.1226720997594524412@siddh.me>
On Wed, Aug 03, 2022 at 09:34:10AM +0530, Siddh Raman Pant wrote:
> On Wed, 03 Aug 2022 03:57:19 +0530 Eric Biggers <ebiggers@kernel.org> wrote:
> > It appears this was already fixed, so no need for any more activity on this bug:
> >
> > #syz fix: watchqueue: make sure to serialize 'wqueue->defunct' properly
> >
> > - Eric
>
> It doesn't address the dangling pointer remaining in the watch_queue,
> which was the root cause of this crash. The use-after-free happened
> because the pipe was freed but a dangling pointer of it remained in
> a watch_queue, and an attempt to dereference it was there.
>
I don't think that's true; the pointer doesn't get dereferenced after
watch_queue::defunct is set. See my message on the other thread where I
explained this: https://lore.kernel.org/lkml/YunKlJCDlmyn2hJ4@sol.localdomain
Of course, if you actually have a reproducer, or a KASAN report, or anything at
all that shows there is still a problem, then please post it.
- Eric
next prev parent reply other threads:[~2022-08-03 4:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220801103533.972-1-hdanton@sina.com>
2022-08-01 10:54 ` [syzbot] KASAN: use-after-free Read in post_one_notification syzbot
2022-08-02 22:27 ` Eric Biggers
2022-08-03 4:04 ` Siddh Raman Pant
2022-08-03 4:09 ` Eric Biggers [this message]
2022-08-03 5:17 ` Siddh Raman Pant
[not found] <20220723142031.2316-1-hdanton@sina.com>
2022-07-23 14:39 ` syzbot
2022-03-21 13:25 syzbot
2022-03-21 15:40 ` David Howells
2022-03-22 7:52 ` Dmitry Vyukov
2022-07-23 13:20 ` Siddh Raman Pant
2022-07-23 13:21 ` syzbot
2022-07-23 13:22 ` Siddh Raman Pant
2022-07-23 13:42 ` syzbot
2022-07-24 3:41 ` Siddh Raman Pant
2022-07-24 4:01 ` syzbot
2022-07-28 15:30 ` Siddh Raman Pant
2022-07-28 15:50 ` syzbot
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