linux-kernel - Re: [PATCH] [RFC] Revert "bpf: Fix ORC unwinding in non-JIT BPF code"

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

Message-ID: <20190708130010.pnxlzi5vptuyppxz@treble>
Date:   Mon, 8 Jul 2019 08:11:10 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>, netdev@...r.kernel.org,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [RFC] Revert "bpf: Fix ORC unwinding in non-JIT BPF code"

On Mon, Jul 08, 2019 at 02:45:23PM +0200, Arnd Bergmann wrote:
> Apparently this was a bit premature, at least I still get this
> warning with gcc-8.1:
> 
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x44d2: sibling call from callable instruction with modified stack frame
> 
> This reverts commit b22cf36c189f31883ad0238a69ccf82aa1f3b16b.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Yes, I have been working on a fix.

The impact is that ORC unwinding is broken in this function for
CONFIG_RETPOLINE=n.

I don't think we want to revert this patch though, because that will
broaden the impact to the CONFIG_RETPOLINE=y case.  Anyway I hope to
have fixes soon.

-- 
Josh