On Mon, Feb 28, 2022 at 11:04:47AM +0530, Maninder Singh wrote:
> with commit '82b37e632513 ("kallsyms: print module name in %ps/S
> case when KALLSYMS is disabled"), module name printing was enhanced.
>
> As per suggestion from Petr Mladek <pmladek@xxxxxxxx>, covering
> other flavours also to print build id also.
>
> for %pB no change as it needs to know symbol name to adjust address
> value which can't be done without KALLSYMS.
>
> 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]
>
> original output without KALLSYMS:
> [12.487424] ps 0xffff800000eb008c
> [12.487598] pS 0xffff800000eb008c
> [12.487723] pSb 0xffff800000eb008c
> [12.487850] pB 0xffff800000eb008c
> [12.487967] pBb 0xffff800000eb008c
>
> With patched kernel without KALLSYMS:
> [9.205207] ps 0xffff800000eb008c [crash]
> [9.205564] pS 0xffff800000eb0000+0x8c [crash]
> [9.205757] pSb 0xffff800000eb0000+0x8c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3]
> [9.206066] pB 0xffff800000eb0000+0x8c [crash]
> [9.206257] pBb 0xffff800000eb0000+0x8c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3]
...
> +static int sprint_module_info(char *buf, char *end, unsigned long value,
> + const char *fmt)
> +{
> + struct module *mod;
> + unsigned long offset = 1;
> + unsigned long base;
> + int ret = 0;
This is hard to find if it's not close to the first use.
Since you are using positive numbers...
> + const char *modname;
> + int modbuildid = 0;
> + int len;
> +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
> + const unsigned char *buildid = NULL;
> +#endif
> +
> + if (is_ksym_addr(value))
> + return 0;
> + if (*fmt == 'B' && fmt[1] == 'b')
> + modbuildid = 1;
> + else if (*fmt == 'S' && (fmt[1] == 'b' || (fmt[1] == 'R' && fmt[2] == 'b')))
Why not to split to two conditionals? Would be easier to get,
> + modbuildid = 1;
> + else if (*fmt != 's') {
These all are inconsistent, please switch to fmt[0].
> + /*
> + * do nothing.
> + */
> + } else
> + offset = 0;
> +
> + preempt_disable();
> + mod = __module_address(value);
> + if (mod) {
> + ret = 1;
> + modname = mod->name;
> +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
> + if (modbuildid)
> + buildid = mod->build_id;
> +#endif
> + if (offset) {
> + base = (unsigned long)mod->core_layout.base;
> + offset = value - base;
> + }
> + }
> +
> + preempt_enable();
> + if (!ret)
This looks a bit strange, but okay, I'm not familiar with the function of this
code.
> + return 0;
> +
> + /* address belongs to module */
> + if (offset)
> + len = sprintf(buf, "0x%lx+0x%lx", base, offset);
> + else
> + len = sprintf(buf, "0x%lx", value);
> +
> + len += sprintf(buf + len, " [%s", modname);
> +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
> + if (modbuildid && buildid) {
> + /* build ID should match length of sprintf */
> + static_assert(sizeof(typeof_member(struct module, build_id)) == 20);
> + len += sprintf(buf + len, " %20phN", buildid);
> + }
> +#endif
> + len += sprintf(buf + len, "]");
> +
> + return len;
> +}
--
With Best Regards,
Andy Shevchenko
