[PATCH] recordmcount: arm64: replace the ignored mcount call into nop

? 2015/10/29 23:09, Will Deacon ??:

On Thu, Oct 29, 2015 at 09:35:42PM +0800, kbuild test robot wrote:

quoted

[auto build test ERROR on arm64/for-next/core -- if it's inappropriate base, please suggest rules for selecting the more suitable base]

url:    https://github.com/0day-ci/linux/commits/Li-Bin/recordmcount-arm64-replace-the-ignored-mcount-call-into-nop/20151028-160846
config: arm64-allmodconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm64 

All errors (new ones prefixed by >>):

quoted

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/bin/bash: line 1: 117734 Segmentation fault      ./scripts/recordmcount "arch/arm64/kernel/traps.o"

--

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/bin/bash: line 1: 113824 Segmentation fault      ./scripts/recordmcount "arch/arm64/mm/fault.o"

I can reproduce this locally with an allmodconfig build. The offset
parameter to make_nop_arm64 is nuts:

  Program received signal SIGSEGV, Segmentation fault.
  make_nop_arm64 (map=0x7ffff7fef000, offset=2600547309829750784) at scripts/recordmcount.c:170
  170		if (*ptr != 0x94000000)

Both shdr->sh_offset (0x17000000000000) and relp->r_offset (0x2400000000000000)
look dodgy in the caller.

The allmodconfig configs the CONFIG_CPU_BIG_ENDIAN, and the test system is little eddian, so
it triggers the error.

It is a bug in nop_mcount:
...
if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
        if (make_nop) {
                ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
        }
...

shdr->sh_offset and welp->r_offset should handle endianness properly as _w(shdr->sh_offset)/
_w(relp->r_offset). I will post a patchset including this patch soon.

Thanks,

Li Bin

Li, can you take a look please?

Will

.