From: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
To: ast@kernel.org, christophe.leroy@csgroup.eu,
daniel@iogearbox.net, Hari Bathini <hbathini@linux.ibm.com>,
jniethe5@gmail.com, mpe@ellerman.id.au
Cc: songliubraving@fb.com, netdev@vger.kernel.org,
john.fastabend@gmail.com, kpsingh@kernel.org,
stable@vger.kernel.org, andrii@kernel.org, paulus@samba.org,
yhs@fb.com, bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
kafai@fb.com
Subject: Re: [PATCH] powerpc/bpf: fix write protecting JIT code
Date: Mon, 25 Oct 2021 11:45:23 +0530 [thread overview]
Message-ID: <1635142354.46h6w5c2rx.naveen@linux.ibm.com> (raw)
In-Reply-To: <20211025055649.114728-1-hbathini@linux.ibm.com>
Hari Bathini wrote:
> Running program with bpf-to-bpf function calls results in data access
> exception (0x300) with the below call trace:
>
> [c000000000113f28] bpf_int_jit_compile+0x238/0x750 (unreliable)
> [c00000000037d2f8] bpf_check+0x2008/0x2710
> [c000000000360050] bpf_prog_load+0xb00/0x13a0
> [c000000000361d94] __sys_bpf+0x6f4/0x27c0
> [c000000000363f0c] sys_bpf+0x2c/0x40
> [c000000000032434] system_call_exception+0x164/0x330
> [c00000000000c1e8] system_call_vectored_common+0xe8/0x278
>
> as bpf_int_jit_compile() tries writing to write protected JIT code
> location during the extra pass.
>
> Fix it by holding off write protection of JIT code until the extra
> pass, where branch target addresses fixup happens.
>
> Cc: stable@vger.kernel.org
> Fixes: 62e3d4210ac9 ("powerpc/bpf: Write protect JIT code")
> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
> ---
> arch/powerpc/net/bpf_jit_comp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Thanks for the fix!
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
next prev parent reply other threads:[~2021-10-25 6:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-25 5:56 [PATCH] powerpc/bpf: fix write protecting JIT code Hari Bathini
2021-10-25 6:15 ` Naveen N. Rao [this message]
2021-10-25 22:54 ` Daniel Borkmann
2021-10-29 1:50 ` Michael Ellerman
2021-11-02 11:59 ` Naveen N. Rao
2021-11-02 13:48 ` Michael Ellerman
2021-11-02 17:34 ` Andrii Nakryiko
2021-11-02 10:12 ` Michael Ellerman
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