From: David Drysdale <drysdale@google.com>
To: Kees Cook <keescook@chromium.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Will Drewry <wad@chromium.org>, Ingo Molnar <mingo@kernel.org>
Cc: Alok Kataria <akataria@vmware.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Borislav Petkov <bp@alien8.de>,
Alexei Starovoitov <ast@plumgrid.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>, X86 ML <x86@kernel.org>
Subject: [Regression v4.2 ?] 32-bit seccomp-BPF returned errno values wrong in VM?
Date: Thu, 13 Aug 2015 09:30:26 +0100 [thread overview]
Message-ID: <CAHse=S8UeYVJqRBx-_wf=jeDERTJxzM=YRH5izBpQnrCHOxcDA@mail.gmail.com> (raw)
Hi folks,
I've got an odd regression with the v4.2 rc kernel, and I wondered if anyone
else could reproduce it.
The problem occurs with a seccomp-bpf filter program that's set up to return
an errno value -- an errno of 1 is always returned instead of what's in the
filter, plus other oddities (selftest output below).
The problem seems to need a combination of circumstances to occur:
- The seccomp-bpf userspace program needs to be 32-bit, running against a
64-bit kernel -- I'm testing with seccomp_bpf from
tools/testing/selftests/seccomp/, built via 'CFLAGS=-m32 make'.
- The kernel needs to be running as a VM guest -- it occurs inside my
VMware Fusion host, but not if I run on bare metal. Kees tells me he
cannot repro with a kvm guest though.
Bisecting indicates that the commit that induces the problem is
3f5159a9221f19b0, "x86/asm/entry/32: Update -ENOSYS handling to match the
64-bit logic", included in all the v4.2-rc* candidates.
Apologies if I've just got something odd with my local setup, but the
bisection was unequivocal enough that I thought it worth reporting...
Thanks,
David
seccomp_bpf failure outputs:
seccomp_bpf.c:533:global.ERRNO_valid:Expected 7 (7) ==
(*__errno_location ()) (1)
seccomp_bpf.c:560:global.ERRNO_zero:Expected 0 (0) == read(0, ((void
*)0), 0) (4294967295)
seccomp_bpf.c:587:global.ERRNO_capped:Expected 4095 (4095) ==
(*__errno_location ()) (1)
seccomp_bpf.c:905:precedence.errno_is_third:Expected 0 (0) ==
syscall(20) (4294967295)
seccomp_bpf.c:925:precedence.errno_is_third_in_any_order:Expected 0
(0) == syscall(20) (4294967295)
next reply other threads:[~2015-08-13 8:30 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 8:30 David Drysdale [this message]
2015-08-13 15:17 ` [Regression v4.2 ?] 32-bit seccomp-BPF returned errno values wrong in VM? Denys Vlasenko
2015-08-13 16:28 ` David Drysdale
2015-08-13 17:15 ` Andy Lutomirski
2015-08-13 17:39 ` David Drysdale
2015-08-13 18:47 ` Kees Cook
2015-08-13 21:35 ` Denys Vlasenko
2015-08-13 21:47 ` Andy Lutomirski
2015-08-13 22:49 ` Linus Torvalds
2015-08-13 22:54 ` Linus Torvalds
2015-08-13 22:56 ` Kees Cook
2015-08-13 22:59 ` Andy Lutomirski
2015-08-13 23:14 ` Kees Cook
2015-08-13 23:30 ` Linus Torvalds
2015-08-14 11:58 ` Denys Vlasenko
2015-08-14 14:27 ` Andy Lutomirski
2015-08-14 7:33 ` David Drysdale
2015-08-13 22:58 ` Andy Lutomirski
2015-08-13 23:25 ` Linus Torvalds
2015-08-13 22:27 ` Linus Torvalds
2015-08-14 11:20 ` Denys Vlasenko
2015-08-22 10:03 ` Ingo Molnar
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