From: Marat Khalili <marat.khalili@huawei.com>
To: Jerin Jacob <jerinjacobk@gmail.com>
Cc: Konstantin Ananyev <konstantin.ananyev@huawei.com>,
Stephen Hemminger <stephen@networkplumber.org>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: RE: [PATCH 1/3] bpf: fix signed shift overflows in ARM JIT
Date: Wed, 12 Nov 2025 10:16:45 +0000 [thread overview]
Message-ID: <0f7fdd71245e419491ea4047503a9bc6@huawei.com> (raw)
In-Reply-To: <CALBAE1MjtM+kVA31KEcge47F_J8qmUDH_q8eWzYjBZxqVppJiQ@mail.gmail.com>
> > > > That tests do trigger it.
> > > >
> > > > RTE>>bpf_autotest
> > > > ../../src/lib/bpf/bpf_jit_arm64.c:320:18: runtime error: left shift of 1 by 31 places cannot be
> > > represented in type 'int'
> > >
> > > This is when ASAN is enabled. Right?
> >
> > More likely UBSAN, but yes.
> >
> > > Is it really generating BAD
> > > opcode(i.e emiter generating bad OPcode) and test fails?
> >
> > If allowed to finish the test does not fail.
>
> Does that mean, it is a false positive? Right?
It depends on who you ask. Certain compilers with certain compilation options
tend to delete execution branches that cause UB, and the test may not be
detailed enough to notice this.
> Anyway, There is no harm in the new patch, Change the patch to use
> SHIFT macros from EAL.
Ok, will do. It is probably too late for the current release anyway.
next prev parent reply other threads:[~2025-11-12 10:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-10 15:30 [PATCH 0/3] bpf: simple tests and fixes Marat Khalili
2025-11-10 15:30 ` [PATCH 1/3] bpf: fix signed shift overflows in ARM JIT Marat Khalili
2025-11-11 6:25 ` Jerin Jacob
2025-11-11 7:53 ` Morten Brørup
2025-11-11 10:10 ` Marat Khalili
2025-11-11 16:29 ` Jerin Jacob
2025-11-11 16:31 ` Jerin Jacob
2025-11-11 16:39 ` Marat Khalili
2025-11-12 5:23 ` Jerin Jacob
2025-11-12 10:16 ` Marat Khalili [this message]
2025-11-10 15:30 ` [PATCH 2/3] bpf: disallow empty program Marat Khalili
2025-11-10 16:40 ` Stephen Hemminger
2025-11-10 16:46 ` Marat Khalili
2025-11-10 15:30 ` [PATCH 3/3] bpf: make add/subtract one program validate Marat Khalili
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