Re: [bug?] Access was denied by memory protection keys in execute-only address

[Li Wang <liwang@xxxxxxxxxx>]

On Thu, Mar 8, 2018 at 8:43 AM, Ram Pai <linuxram@xxxxxxxxxx> wrote:

On Wed, Mar 07, 2018 at 04:09:06PM +0800, Li Wang wrote:
>    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 ​
>    ​&exec_func = 0x10030170​
>    ​&func = 0x7fffa6c60170​
>
>    ​While perform ​"(*func)();" we get the
>    ​segmentation fault.
>    ​
>    ​strace log:​
>    -------------------
>    ​mprotect(0x7fffaed00000, 131072, PROT_EXEC) = 0
>    rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
>    --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_PKUERR,
>    si_addr=0x7fffaed00170} ---​

Ran the same test on my machine. and did not encounter the bug.

Can I get your kernel .config ?

​S​

ee the attachment.
 

also is this a P7 LPAR or a P8 LPAR?  cat /proc/cpuinfo will help.

 

One is

​IBM LPAR on P730 {8231-E2B}​

, another is:

​IBM Power 8 8247-22L​

​# ./mprotect04
mprotect04    1  TPASS  :  test PROT_NONE for mprotect success
mprotect04    2  TFAIL  :  mprotect04.c:252: test PROT_EXEC for mprotect failed​

​# cat /proc/cpuinfo
processor    : 0
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 1
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 2
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 3
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 4
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 5
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 6
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

processor    : 7
cpu        : POWER8 (architected), altivec supported
clock        : 3425.000000MHz
revision    : 2.1 (pvr 004b 0201)

timebase    : 512000000
platform    : pSeries
model        : IBM,8247-22L
machine        : CHRP IBM,8247-22L
MMU        : Hash

--

Li Wang
liwang@xxxxxxxxxx

Attachment: config-4.16.0-rc3
Description: Binary data