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From: Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [bug?] Access was denied by memory protection keys in execute-only address
In-Reply-To: <CAEemH2f0LDqyR5AmUYv17OuBc5-UycckDPWgk46XU_ghQo4diw@mail.gmail.com>
References: <CAEemH2f0LDqyR5AmUYv17OuBc5-UycckDPWgk46XU_ghQo4diw@mail.gmail.com>
Date: Thu, 08 Mar 2018 23:19:12 +1100
Message-ID: <871sguep4v.fsf@concordia.ellerman.id.au>
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Sender: owner-linux-mm@kvack.org
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To: Li Wang <liwang@redhat.com>, linuxram@us.ibm.com
Cc: Jan Stancek <jstancek@redhat.com>, ltp@lists.linux.it, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.orglinuxppc-dev@lists.ozlabs.org

Li Wang <liwang@redhat.com> writes:
> Hi,
>
> ltp/mprotect04[1] crashed by SEGV_PKUERR on ppc64(LPAR on P730, Power 8
> 8247-22L) with kernel-v4.16.0-rc4.
>
> 10000000-10020000 r-xp 00000000 fd:00 167223           mprotect04
> 10020000-10030000 r--p 00010000 fd:00 167223           mprotect04
> 10030000-10040000 rw-p 00020000 fd:00 167223           mprotect04
> 1001a380000-1001a3b0000 rw-p 00000000 00:00 0          [heap]
> 7fffa6c60000-7fffa6c80000 --xp 00000000 00:00 0 =E2=80=8B
>
> =E2=80=8B&exec_func =3D 0x10030170=E2=80=8B
>
> =E2=80=8B&func =3D 0x7fffa6c60170=E2=80=8B
>
> =E2=80=8BWhile perform =E2=80=8B
> "(*func)();" we get the
> =E2=80=8Bsegmentation fault.
> =E2=80=8B
>
> =E2=80=8Bstrace log:=E2=80=8B
>
> -------------------
> =E2=80=8Bmprotect(0x7fffaed00000, 131072, PROT_EXEC) =3D 0
> rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  =3D 0
> --- SIGSEGV {si_signo=3DSIGSEGV, si_code=3DSEGV_PKUERR, si_addr=3D0x7fffa=
ed00170}
> ---=E2=80=8B

Looks like a bug to me.

Please Cc linuxppc-dev on powerpc bugs.

I also can't reproduce this failure on my machine.
Not sure what's going on?

cheers