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perf unwind-libdw: Handle JIT-generated DSOs properly

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Usually DSOs are mapped from the beginning of the file, so the base
address of the DSO can be calculated by map->start - map->pgoff.

However, JIT DSOs which are generated by `perf inject -j`, are mapped
only the code segment.  This makes unwind-libdw code confusing and
rejects processing unwinds in the JIT DSOs.  It should use the map
start address as base for them to fix the confusion.

Fixes: 1fe627da30 ("perf unwind: Take pgoff into account when reporting elf to libdwfl")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Fangrui Song <maskray@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Pablo Galindo <pablogsal@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231212070547.612536-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2023-12-11 23:05:45 -08:00 committed by Arnaldo Carvalho de Melo
parent 1af478903f
commit c966d23a35
1 changed files with 17 additions and 4 deletions
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21
tools/perf/util/unwind-libdw.c
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@ -46,6 +46,7 @@ static int __report_module(struct addr_location *al, u64 ip,
{
Dwfl_Module *mod;
struct dso *dso = NULL;
Dwarf_Addr base;
/*
* Some callers will use al->sym, so we can't just use the
* cheaper thread__find_map() here.
@ -58,13 +59,25 @@ static int __report_module(struct addr_location *al, u64 ip,
if (!dso)
return 0;
/*
* The generated JIT DSO files only map the code segment without
* ELF headers. Since JIT codes used to be packed in a memory
* segment, calculating the base address using pgoff falls into
* a different code in another DSO. So just use the map->start
* directly to pick the correct one.
*/
if (!strncmp(dso->long_name, "/tmp/jitted-", 12))
base = map__start(al->map);
else
base = map__start(al->map) - map__pgoff(al->map);
mod = dwfl_addrmodule(ui->dwfl, ip);
if (mod) {
Dwarf_Addr s;
dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
if (s != map__start(al->map) - map__pgoff(al->map))
mod = 0;
if (s != base)
mod = NULL;
}
if (!mod) {
@ -72,14 +85,14 @@ static int __report_module(struct addr_location *al, u64 ip,
__symbol__join_symfs(filename, sizeof(filename), dso->long_name);
mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1,
map__start(al->map) - map__pgoff(al->map), false);
base, false);
}
if (!mod) {
char filename[PATH_MAX];
if (dso__build_id_filename(dso, filename, sizeof(filename), false))
mod = dwfl_report_elf(ui->dwfl, dso->short_name, filename, -1,
map__start(al->map) - map__pgoff(al->map), false);
base, false);
}
if (mod) {