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From: Leon Romanovsky <leon@kernel.org>
To: asmadeus@codewreck.org
Cc: syzbot <syzbot+67d13108d855f451cafc@syzkaller.appspotmail.com>,
	davem@davemloft.net, edumazet@google.com, ericvh@gmail.com,
	kuba@kernel.org, linux-kernel@vger.kernel.org,
	linux_oss@crudebyte.com, lucho@ionkov.net,
	netdev@vger.kernel.org, pabeni@redhat.com,
	syzkaller-bugs@googlegroups.com,
	v9fs-developer@lists.sourceforge.net
Subject: Re: [syzbot] KASAN: use-after-free Read in rdma_close
Date: Wed, 28 Sep 2022 13:49:19 +0300	[thread overview]
Message-ID: <YzQmr8LVTmUj9+zB@unreal> (raw)
In-Reply-To: <YzQlWq9EOi9jpy46@codewreck.org>

On Wed, Sep 28, 2022 at 07:43:38PM +0900, asmadeus@codewreck.org wrote:
> Leon Romanovsky wrote on Wed, Sep 28, 2022 at 01:07:23PM +0300:
> > The bug is in commit 3ff51294a055 ("9p: p9_client_create: use p9_client_destroy on failure").
> 
> Thanks for looking
> 
> > It is wrong to call to p9_client_destroy() if clnt->trans_mod->create fails.
> 
> hmm that's a bit broad :)
> 
> But I agree I did get that wrong: trans_mod->close() wasn't called if
> create failed.
> We do want the idr_for_each_entry() that is in p9_client_destroy so
> rather than revert the commit (fix a bug, create a new one..) I'd rather
> split it out in an internal function that takes a 'bool close' or
> something to not duplicate the rest.
> (Bit of a nitpick, sure)

Please do proper unwind without extra variable.

Proper unwind means that you will call to symmetrical functions in
destroy as you used in create:
alloc -> free
create -> close
e.t.c

When you use some global function like you did, there is huge chance
to see unwind bugs.

> 
> I'll send a patch and credit you in Reported-by unless you don't want
> to.
> 
> -- 
> Dominique

  reply	other threads:[~2022-09-28 10:49 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-25 11:29 [syzbot] KASAN: use-after-free Read in rdma_close syzbot
2022-09-28 10:07 ` Leon Romanovsky
2022-09-28 10:43   ` asmadeus
2022-09-28 10:49     ` Leon Romanovsky [this message]
2022-09-28 11:23       ` asmadeus
2022-09-28 11:54         ` Leon Romanovsky
2022-09-28 12:57           ` Christian Schoenebeck
2022-09-28 21:52             ` asmadeus
2022-09-29  6:10               ` Leon Romanovsky
2022-09-28 21:44   ` [PATCH 1/2] 9p: client_create/destroy: only call trans_mod->close after create Dominique Martinet
2022-09-28 21:44     ` [PATCH 2/2] 9p: client_create: init fcall_cache earlier Dominique Martinet
2022-09-29  5:57       ` Leon Romanovsky
2022-09-29  7:03         ` Dominique Martinet
2022-09-28 21:58     ` [PATCH 1/2 v2] 9p: client_create/destroy: only call trans_mod->close after create Dominique Martinet
2022-09-28 22:19       ` [PATCH v3] " Dominique Martinet
2022-09-29  5:54         ` Leon Romanovsky
2022-09-29  7:24           ` Dominique Martinet
2022-12-30 10:34 ` [syzbot] KASAN: use-after-free Read in rdma_close syzbot
2023-01-13 10:35 ` syzbot
2023-01-27 10:36 ` syzbot
2023-02-10 10:36 ` syzbot
2023-02-24 10:37 ` syzbot
2023-03-10 10:38 ` syzbot
2023-03-24 10:38 ` syzbot
2023-04-07 10:38 ` syzbot
2023-04-21 10:39 ` syzbot
2023-05-05 10:40 ` syzbot
2023-05-19 10:40 ` syzbot
2023-06-02 10:42 ` syzbot
2023-06-02 10:57   ` Aleksandr Nogikh

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