Messages in this thread | | | Date | Wed, 7 Apr 2021 17:03:47 +0200 | From | Petr Mladek <> | Subject | Re: [PATCH v3 04/12] module: Add printk format to add module build ID to stacktraces |
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On Tue 2021-03-30 20:05:12, Stephen Boyd wrote: > Let's make kernel stacktraces easier to identify by including the build > ID[1] of a module if the stacktrace is printing a symbol from a module. > This makes it simpler for developers to locate a kernel module's full > debuginfo for a particular stacktrace. Combined with > scripts/decode_stracktrace.sh, a developer can download the matching > debuginfo from a debuginfod[2] server and find the exact file and line > number for the functions plus offsets in a stacktrace that match the > module. This is especially useful for pstore crash debugging where the > kernel crashes are recorded in something like console-ramoops and the > recovery kernel/modules are different or the debuginfo doesn't exist on > the device due to space concerns (the debuginfo can be too large for > space limited devices). > > @@ -359,15 +369,17 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size, > > /* Look up a kernel symbol and return it in a text buffer. */ > static int __sprint_symbol(char *buffer, unsigned long address, > - int symbol_offset, int add_offset) > + int symbol_offset, int add_offset, int add_buildid) > { > char *modname; > + const unsigned char *buildid; > const char *name; > unsigned long offset, size; > int len; > > address += symbol_offset; > - name = kallsyms_lookup(address, &size, &offset, &modname, buffer); > + name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid, > + buffer); > if (!name) > return sprintf(buffer, "0x%lx", address - symbol_offset); > > @@ -379,8 +391,12 @@ static int __sprint_symbol(char *buffer, unsigned long address, > if (add_offset) > len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
Please add something like:
/* Keep BUILD_ID_SIZE_MAX in sync with the below used %20phN */ BUILD_BUG_ON(BUILD_ID_SIZE_MAX != 20)
to make sure the the hard
> > - if (modname) > - len += sprintf(buffer + len, " [%s]", modname); > + if (modname) { > + len += sprintf(buffer + len, " [%s", modname); > + if (IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) && add_buildid && buildid) > + len += sprintf(buffer + len, " %20phN", buildid); > + len += sprintf(buffer + len, "]"); > + } > > return len; > }
Otherwise the approach looks fine to me. The main problem is that it does not work for me as described in the other reply ;-)
Best Regards, Petr
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