Em Mon, Nov 26, 2018 at 09:39:17AM +0100, Jiri Olsa escreveu: > On Fri, Nov 23, 2018 at 10:24:21AM -0800, Eric Saint Etienne wrote: > > > > + /* > > > > + * When using -ffunction-sections, only .text gets > > > > loaded by > > > > + * map_groups__find() into al->map. Consequently > > > > al->map address > > > > + * range encompass the whole code. > > > > + * > > > > + * But map__load() has just loaded many function maps by > > > > + * splitting al->map, which reduced al->map range > > > > drastically. > > > > + * Very likely the target address is now in one of > > > > those newly > > > > + * created function maps, so we need to lookup the map > > > > again > > > > + * to find that new map. > > > > + */ > > > > > > hum, so map__load actualy can split the map to create new maps? > > > > > > cold you please point me to that code? I haven't touch this area for some > > > time and I can't find it > > > > The split happens in dso_process_kernel_symbol() in symbol-elf.c where we > > call map_groups__find_by_name() to find an existing map, but with > > -ffunction-sections and a symbol belonging to new (function) map, such map > > doesn't exist yet so we end up creating one and adjusting existing maps > > accordingly because adjust_kernel_syms is set. Makes sense? > > > > As of 4.20-rc3 the call chain is as follows: > > event:c:1573 map__load() > > map.c:315 dso__load() > > symobl.c:1528 dso__load_kernel_sym() > > symbol.c:1896 dso__load_vmlinux_path() > > (or we directly call dso__load_vmlinux() at line 1892) > > symbol.c:1744 dso__load_vmlinux() > > symbol.c:1719 dso__load_sym() > > symbol-elf.c:1090 dso_process_kernel_symbol() > > i see, thank for the pointers.. could you please mention > this in your comment and changelog as well? > > also to document in the code that it's related to map__load > could you put it to the if contidion, like: > > + if (load_map && (al->addr < al->map->start || al->addr >= > al->map->end)) >
Eric, please address Jiri's comments and send a v2, ok? - Arnaldo
