From: Yonghong Song <yonghong.song@linux.dev>
To: Ilya Leoshkevich <iii@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>
Subject: Re: [PATCH bpf-next 01/11] bpf: Disable zero-extension for BPF_MEMSX
Date: Fri, 1 Sep 2023 06:40:24 -0400 [thread overview]
Message-ID: <3602cc26-bcc7-d7e1-2183-53a3a1b93d91@linux.dev> (raw)
In-Reply-To: <20230830011128.1415752-2-iii@linux.ibm.com>
On 8/29/23 9:07 PM, Ilya Leoshkevich wrote:
> On the architectures that use bpf_jit_needs_zext(), e.g., s390x, the
> verifier incorrectly inserts a zero-extension after BPF_MEMSX, leading
> to miscompilations like the one below:
>
> 24: 89 1a ff fe 00 00 00 00 "r1 = *(s16 *)(r10 - 2);" # zext_dst set
> 0x3ff7fdb910e: lgh %r2,-2(%r13,%r0) # load halfword
> 0x3ff7fdb9114: llgfr %r2,%r2 # wrong!
> 25: 65 10 00 03 00 00 7f ff if r1 s> 32767 goto +3 <l0_1> # check_cond_jmp_op()
>
> Disable such zero-extensions. The JITs need to insert sign-extension
> themselves, if necessary.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
next prev parent reply other threads:[~2023-09-01 10:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 1:07 [PATCH bpf-next 00/11] Implement cpuv4 support for s390x Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 01/11] bpf: Disable zero-extension for BPF_MEMSX Ilya Leoshkevich
2023-09-01 10:40 ` Yonghong Song [this message]
2023-09-01 14:19 ` Puranjay Mohan
2023-09-01 14:56 ` Puranjay Mohan
2023-09-07 0:39 ` Alexei Starovoitov
2023-09-07 7:33 ` Puranjay Mohan
2023-09-07 15:36 ` Alexei Starovoitov
2023-09-07 16:39 ` Puranjay Mohan
2023-09-07 22:45 ` Alexei Starovoitov
2023-09-07 22:57 ` Puranjay Mohan
2023-09-12 22:49 ` Puranjay Mohan
2023-09-13 0:09 ` Alexei Starovoitov
2023-09-13 0:22 ` Puranjay Mohan
2023-09-13 1:49 ` Alexei Starovoitov
2023-09-13 6:10 ` Christophe Leroy
2023-09-03 8:16 ` Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 02/11] net: netfilter: Adjust timeouts of non-confirmed CTs in bpf_ct_insert_entry() Ilya Leoshkevich
2023-08-31 15:30 ` Daniel Borkmann
2023-09-03 8:23 ` Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 03/11] selftests/bpf: Unmount the cgroup2 work directory Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 04/11] selftests/bpf: Add big-endian support to the ldsx test Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 05/11] s390/bpf: Implement BPF_MOV | BPF_X with sign-extension Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 06/11] s390/bpf: Implement BPF_MEMSX Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 07/11] s390/bpf: Implement unconditional byte swap Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 08/11] s390/bpf: Implement unconditional jump with 32-bit offset Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 09/11] s390/bpf: Implement signed division Ilya Leoshkevich
2023-08-30 1:07 ` [PATCH bpf-next 10/11] selftests/bpf: Enable the cpuv4 tests for s390x Ilya Leoshkevich
2023-09-01 10:41 ` Yonghong Song
2023-08-30 1:07 ` [PATCH bpf-next 11/11] selftests/bpf: Trim DENYLIST.s390x Ilya Leoshkevich
2023-09-14 13:00 ` [PATCH bpf-next 00/11] Implement cpuv4 support for s390x patchwork-bot+netdevbpf
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