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Subject[PATCH] perf symbol: Fail to read phdr workaround
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The perf jvmti agent doesn't create program headers, in this case
fallback on section headers as happened previously.

Fixes: 882528d2e776 ("perf symbol: Skip symbols if SHF_ALLOC flag is not set")
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/symbol-elf.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index b3be5b1d9dbb..75bec32d4f57 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1305,16 +1305,29 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,

if (elf_read_program_header(syms_ss->elf,
(u64)sym.st_value, &phdr)) {
- pr_warning("%s: failed to find program header for "
+ pr_debug4("%s: failed to find program header for "
"symbol: %s st_value: %#" PRIx64 "\n",
__func__, elf_name, (u64)sym.st_value);
- continue;
+ pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
+ "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",
+ __func__, (u64)sym.st_value, (u64)shdr.sh_addr,
+ (u64)shdr.sh_offset);
+ /*
+ * Fail to find program header, let's rollback
+ * to use shdr.sh_addr and shdr.sh_offset to
+ * calibrate symbol's file address, though this
+ * is not necessary for normal C ELF file, we
+ * still need to handle java JIT symbols in this
+ * case.
+ */
+ sym.st_value -= shdr.sh_addr - shdr.sh_offset;
+ } else {
+ pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
+ "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
+ __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
+ (u64)phdr.p_offset);
+ sym.st_value -= phdr.p_vaddr - phdr.p_offset;
}
- pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
- "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
- __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
- (u64)phdr.p_offset);
- sym.st_value -= phdr.p_vaddr - phdr.p_offset;
}

demangled = demangle_sym(dso, kmodule, elf_name);
--
2.37.1.455.g008518b4e5-goog
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