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Message-ID: <fb9febe5-00a6-61e9-a2d0-40982f9721a3@suse.cz>
Date:   Mon, 25 Jul 2022 12:15:24 +0200
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Subject: Re: [syzbot] WARNING in p9_client_destroy
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To:     syzbot <syzbot+5e28cdb7ebd0f2389ca4@syzkaller.appspotmail.com>,
        akpm@linux-foundation.org, asmadeus@codewreck.org,
        davem@davemloft.net, edumazet@google.com, elver@google.com,
        ericvh@gmail.com, hdanton@sina.com, k.kahurani@gmail.com,
        kuba@kernel.org, linux-kernel@vger.kernel.org,
        linux_oss@crudebyte.com, lucho@ionkov.net, netdev@vger.kernel.org,
        pabeni@redhat.com, rientjes@google.com,
        syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org,
        v9fs-developer@lists.sourceforge.net
References: <000000000000e6917605e48ce2bf@google.com>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <000000000000e6917605e48ce2bf@google.com>
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On 7/24/22 15:17, syzbot wrote:
> syzbot has bisected this issue to:
> 
> commit 7302e91f39a81a9c2efcf4bc5749d18128366945
> Author: Marco Elver <elver@google.com>
> Date:   Fri Jan 14 22:03:58 2022 +0000
> 
>     mm/slab_common: use WARN() if cache still has objects on destroy

Just to state the obvious, bisection pointed to a commit that added the
warning, but the reason for the warning would be that p9 is destroying a
kmem_cache without freeing all the objects there first, and that would be
true even before the commit.

> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=142882ce080000
> start commit:   cb71b93c2dc3 Add linux-next specific files for 20220628
> git tree:       linux-next
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=162882ce080000
> console output: https://syzkaller.appspot.com/x/log.txt?x=122882ce080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=badbc1adb2d582eb
> dashboard link: https://syzkaller.appspot.com/bug?extid=5e28cdb7ebd0f2389ca4
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=156f74ee080000
> 
> Reported-by: syzbot+5e28cdb7ebd0f2389ca4@syzkaller.appspotmail.com
> Fixes: 7302e91f39a8 ("mm/slab_common: use WARN() if cache still has objects on destroy")
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection