On Wed 2022-03-16 10:05:40, Maninder Singh wrote:
> print module information when KALLSYMS is disabled.
>
> No change for %pB, as it needs to know symbol name to adjust address
> value which can't be done without KALLSYMS.
>
> (A) original output with KALLSYMS:
> [8.842129] ps function_1 [crash]
> [8.842735] pS function_1+0x4/0x2c [crash]
> [8.842890] pSb function_1+0x4/0x2c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3]
> [8.843175] pB function_1+0x4/0x2c [crash]
> [8.843362] pBb function_1+0x4/0x2c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3]
>
> (B) original output without KALLSYMS:
> [12.487424] ps 0xffff800000eb008c
> [12.487598] pS 0xffff800000eb008c
> [12.487723] pSb 0xffff800000eb008c
> [12.487850] pB 0xffff800000eb008c
> [12.487967] pBb 0xffff800000eb008c
>
> (C) With patched kernel
> with KALLYSMS:
> [41.974576] ps function_1 [crash]
> [41.975173] pS function_1+0x4/0x2c [crash]
> [41.975386] pSb function_1+0x4/0x2c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
> [41.975879] pB function_1+0x4/0x2c [crash]
> [41.976076] pBb function_1+0x4/0x2c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
>
> without KALLSYMS:
> [9.624152] ps 0xffff800001bd008c [crash] // similar to original, no changes
> [9.624548] pS 0x(____ptrval____)+0x8c [crash] // base address hashed and offset is without hash
> [9.624847] pSb 0x(____ptrval____)+0x8c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
> [9.625388] pB 0x(____ptrval____)+0x8c [crash]
> [9.625594] pBb 0x(____ptrval____)+0x8c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
>
> with disable hashing:
> [8.563916] ps 0xffff800000f2008c [crash]
> [8.564574] pS 0xffff800000f20000+0x8c [crash]
> [8.564749] pSb 0xffff800000f20000+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca]
> [8.565008] pB 0xffff800000f20000+0x8c [crash]
> [8.565154] pBb 0xffff800000f20000+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca]
>
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -979,33 +979,92 @@ char *bdev_name(char *buf, char *end, struct block_device *bdev,
> }
> #endif
>
> +#if !defined(CONFIG_KALLSYMS) && defined(CONFIG_MODULES)
> +static int sprint_module_info(char *buf, unsigned long value,
> + int modbuildid, int backtrace, int symbol)
> +{
> + struct module *mod;
> + unsigned long offset;
> + void *base;
> + char *modname;
> + int len;
> + const unsigned char *buildid = NULL;
> + bool add_offset;
> +
> + if (is_ksym_addr(value))
> + return 0;
> +
> + if (backtrace || symbol)
> + add_offset = true;
> + else
> + add_offset = false;
> +
> + preempt_disable();
> + mod = __module_address(value);
> + if (mod) {
> + modname = mod->name;
> +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
> + if (modbuildid)
> + buildid = mod->build_id;
> +#endif
> + if (add_offset) {
> + base = mod->core_layout.base;
> + offset = value - (unsigned long)base;
> + }
> + }
> + preempt_enable();
> + if (!mod)
> + return 0;
I think that some earlier version of the patch allowed to print
also the address from vmlinux with the offset. My concern was
that it would show non-hashed base pointer. IMHO, it is fine
to show it hashed.
> +
> + /* address belongs to module */
> + if (add_offset)
> + len = sprintf(buf, "0x%p+0x%lx", base, offset);
> + else
> + len = sprintf(buf, "0x%lx", value);
> +
> + return len + fill_name_build_id(buf, modname, modbuildid, buildid, len);
> +}
Otherwise, it looks good to me. I did also some basic testing.
The vmlinux address with offset can be added by a followup patch.
Feel free to use:
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Tested-by: Petr Mladek <pmladek@xxxxxxxx>
Best Regards,
Petr
