linux-kernel - Re: [syzbot] WARNING in static_key_slow_try

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <YWW5yN5OCSjRXptm@google.com>
Date:   Tue, 12 Oct 2021 16:37:28 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Cc:     Reiji Watanabe <reijiw@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        syzkaller-bugs@...glegroups.com, linux-kernel@...r.kernel.org,
        syzbot <syzbot+9fc046ab2b0cf295a063@...kaller.appspotmail.com>
Subject: Re: [syzbot] WARNING in static_key_slow_try_dec (2)

On Tue, Oct 12, 2021, Sean Christopherson wrote:
> On Sun, Oct 10, 2021, Tetsuo Handa wrote:
> > Hello.
> > 
> > Commit 4547700a4d190ac4 ("KVM: x86: Consolidate APIC base RESET initialization code")
> 
> That's definitely where the error was made visible,

I take that back, the bug was likely visible even before the redundant vendor code
was dropped.  Doesn't change the fix in any way though.

> but commit 421221234ada ("KVM: x86: Open code necessary bits of
> kvm_lapic_set_base() at vCPU RESET") is the real culprit.  I'll send a patch
> later today.  I'm leaning toward a partial revert with some extra comments.
> 
> Thanks for the debug!  I was having trouble reproducing the syzbot report.