Hi Arun,
-----Original Message-----
> Hi,
>
> I was trying to debug a PPC64 crash from a X86_64 machine. I got crash (7.2.8) to work with a "make
> target=PPC64", but when I tried to load an extension I got this error:
>
>
> crash> extend /root/misc/builds/mpykdump-v3.2.1-g4308a70/Extension/mpykdump.so
> extend: /root/misc/builds/mpykdump-v3.2.1-g4308a70/Extension/mpykdump.so: not an ELF format object
> file
>
>
> I tried other sample extensions (like dminfo) with the same result.
>
> A little debugging shows that "is_shared_object()" is returning FALSE leading to this. Just commenting the
> call makes the extension work as expected.
>
> gdb of is_shared_object():
>
> 3852 } else if ((elf64->e_ident[EI_CLASS] == ELFCLASS64) &&
> (gdb)
> 3854 switch (swap16(elf64->e_machine, swap))
> (gdb) p elf64
> $6 = (Elf64_Ehdr *) 0x7fffffffca40
> (gdb) p *elf64
> $7 = {e_ident = "\177ELF\002\001\001\000\000\000\000\000\000\000\000", e_type = 3, e_machine = 62,
> e_version = 1, e_entry = 511360, e_phoff = 64, e_shoff = 20379704, e_flags = 0, e_ehsize = 64,
> e_phentsize = 56, e_phnum = 7, e_shentsize = 64, e_shnum = 31, e_shstrndx = 28}
> (gdb) p/x *elf64
> $8 = {e_ident = {0x7f, 0x45, 0x4c, 0x46, 0x2, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
> e_type = 0x3, e_machine = 0x3e, e_version = 0x1, e_entry = 0x7cd80, e_phoff = 0x40, e_shoff =
> 0x136f838,
> e_flags = 0x0, e_ehsize = 0x40, e_phentsize = 0x38, e_phnum = 0x7, e_shentsize = 0x40, e_shnum
> = 0x1f,
> e_shstrndx = 0x1c}
> (gdb) n
> 3867 if (machine_type("X86_64") || machine_type("ARM64"))
> (gdb)
> 3877 if (machine_type("ARM64"))
> (gdb)
> 3887 if (CRASHDEBUG(1))
> (gdb) p swap
> $9 = 0
> (gdb) p machine_type("X86_64")
> $10 = 0
> (gdb) p machine_type("PPC64")
> $11 = 1
>
> (gdb) n
> 3793 return FALSE;
>
>
>
> It appears like the fix should be something like this (which does fix the issue), but I'd leave it to experts
> how to fix this correctly:
>
> # diff -up symbols.c.org symbols.c
> --- symbols.c.org 2020-09-02 11:28:33.855265712 -0700
> +++ symbols.c 2020-09-02 11:28:36.964274966 -0700
> @@ -3864,7 +3864,8 @@ is_shared_object(char *file)
> break;
>
> case EM_X86_64:
> - if (machine_type("X86_64") || machine_type("ARM64"))
> + if (machine_type("X86_64") || machine_type("ARM64") ||
> + machine_type("PPC64"))
> return TRUE;
> break;
>
Thank you for catching this. And this patch looks good to me.
Could you post a formal patch?
Thanks,
Kazu
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