[Crash-utility] [PATCH] crash: Use '?' for kernel module symbols type

[Dave Anderson]

----- Original Message -----
> We are using ELFXX_sym->st_info directly as the 'type' of symbol,
> which is wrong, because st_info contains numeric value which needs
> to be mapped to appropriate type character. 

I'm confused here.  If I dump each module symbol's st_info fields as they are
being read/initialized, they always contain the unsigned char ASCII value for
either 't', 'r', 'd', 'b' or 'w'.  What do you mean that it needs to be mapped
to the appropriate type character?

Dave


> Sections headers are
> also required to correctly map st_info to symbol type which are
> missing here (lm->mod_section_data is NULL). Use '?' for now. This
> fixes 'trace' extension which segfaults internally while parsing
> module kallsyms:
>  
> Before patch:
>   crash> trace show
>   crash>
> 
> After patch:
>   crash> trace show
>   cpus=4
>     <idle>-0  [002]  4350.912553: function: __hrtimer_get_next_event <--
>     hrtime
>     <idle>-0  [002]  4350.912553: function: __hrtimer_next_event_base <--
>     __hrt
> 
> Signed-off-by: Ravi Bangoria <ravi.bangoria at linux.ibm.com>
> ---
>  symbols.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/symbols.c b/symbols.c
> index e73e735..4456cd3 100644
> --- a/symbols.c
> +++ b/symbols.c
> @@ -2188,7 +2188,12 @@ Elf32_Sym_to_common(Elf32_Sym *e32, struct elf_common
> *ec)
>  	ec->st_name = (ulong)e32->st_name;
>  	ec->st_value = (ulong)e32->st_value;
>  	ec->st_shndx = (ulong)e32->st_shndx;
> -	ec->st_info = e32->st_info;
> +	/*
> +	 * Section headers are required to correctly map st_info
> +	 * to symbol type, which are missing here. Let's use '?'
> +	 * for all kernel module symbols type.
> +	 */
> +	ec->st_info = '?';
>  	ec->st_size = (ulong)e32->st_size;
>  }
>  
> @@ -2198,7 +2203,12 @@ Elf64_Sym_to_common(Elf64_Sym *e64, struct elf_common
> *ec)
>  	ec->st_name = (ulong)e64->st_name;
>  	ec->st_value = (ulong)e64->st_value;
>  	ec->st_shndx = (ulong)e64->st_shndx;
> -	ec->st_info = e64->st_info;
> +	/*
> +	 * Section headers are required to correctly map st_info
> +	 * to symbol type, which are missing here. Let's use '?'
> +	 * for all kernel module symbols type.
> +	 */
> +	ec->st_info = '?';
>  	ec->st_size = (ulong)e64->st_size;
>  }
>  
> --
> 1.8.3.1
> 
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