linux-kernel - ebpf: BPF_ALU32 | BPF

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Message-ID: <xunyo92mox9h.fsf@redhat.com>
Date:   Tue, 25 Jun 2019 12:00:10 +0300
From:   Yauheni Kaliuta <yauheni.kaliuta@...hat.com>
To:     Jiong Wang <jiong.wang@...ronome.com>
Cc:     linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...hat.com>,
        Jiri Benc <jbenc@...hat.com>
Subject: ebpf: BPF_ALU32 | BPF_ARSH on BE arches

Hi!

Looks like the code:

       ALU_ARSH_X:
               DST = (u64) (u32) ((*(s32 *) &DST) >> SRC);
               CONT;
       ALU_ARSH_K:
               DST = (u64) (u32) ((*(s32 *) &DST) >> IMM);
               CONT;

works incorrectly on BE arches since it must operate on lower
parts of 64bit registers.

See failure of test_verifier test 'arsh32 on imm 2' (#23 on
5.2-rc6).


-- 
WBR,
Yauheni Kaliuta