diff options
author | Namhyung Kim | 2024-02-12 15:33:22 -0800 |
---|---|---|
committer | Namhyung Kim | 2024-02-16 16:07:28 -0800 |
commit | bacefe0c7b77b7527a613e053b6d378412a8a779 (patch) | |
tree | db162f3ec5e37f61b6acc4708ff902d9e811d539 /tools/perf | |
parent | 6f146b249b3ada0082209b34abf01c90c702a96b (diff) |
perf tools: Fixup module symbol end address properly
I got a strange error on ARM to fail on processing FINISHED_ROUND
record. It turned out that it was failing in symbol__alloc_hist()
because the symbol size is too big.
When a sample is captured on a specific BPF program, it failed. I've
added a debug code and found the end address of the symbol is from
the next module which is placed far way.
ffff800008795778-ffff80000879d6d8: bpf_prog_1bac53b8aac4bc58_netcg_sock [bpf]
ffff80000879d6d8-ffff80000ad656b4: bpf_prog_76867454b5944e15_netcg_getsockopt [bpf]
ffff80000ad656b4-ffffd69b7af74048: bpf_prog_1d50286d2eb1be85_hn_egress [bpf] <---------- here
ffffd69b7af74048-ffffd69b7af74048: $x.5 [sha3_generic]
ffffd69b7af74048-ffffd69b7af740b8: crypto_sha3_init [sha3_generic]
ffffd69b7af740b8-ffffd69b7af741e0: crypto_sha3_update [sha3_generic]
The logic in symbols__fixup_end() just uses curr->start to update the
prev->end. But in this case, it won't work as it's too different.
I think ARM has a different kernel memory layout for modules and BPF
than on x86. Actually there's a logic to handle kernel and module
boundary. Let's do the same for symbols between different modules.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Leo Yan <leo.yan@linux.dev>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20240212233322.1855161-1-namhyung@kernel.org
Diffstat (limited to 'tools/perf')
-rw-r--r-- | tools/perf/util/symbol.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 35975189999b..9ebdb8e13c0b 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -248,14 +248,31 @@ void symbols__fixup_end(struct rb_root_cached *symbols, bool is_kallsyms) * segment is very big. Therefore do not fill this gap and do * not assign it to the kernel dso map (kallsyms). * + * Also BPF code can be allocated separately from text segments + * and modules. So the last entry in a module should not fill + * the gap too. + * * In kallsyms, it determines module symbols using '[' character * like in: * ffffffffc1937000 T hdmi_driver_init [snd_hda_codec_hdmi] */ if (prev->end == prev->start) { + const char *prev_mod; + const char *curr_mod; + + if (!is_kallsyms) { + prev->end = curr->start; + continue; + } + + prev_mod = strchr(prev->name, '['); + curr_mod = strchr(curr->name, '['); + /* Last kernel/module symbol mapped to end of page */ - if (is_kallsyms && (!strchr(prev->name, '[') != - !strchr(curr->name, '['))) + if (!prev_mod != !curr_mod) + prev->end = roundup(prev->end + 4096, 4096); + /* Last symbol in the previous module */ + else if (prev_mod && strcmp(prev_mod, curr_mod)) prev->end = roundup(prev->end + 4096, 4096); else prev->end = curr->start; |