[PATCH 03/10] perf symbols: Check plt_entry_size is not zero

From: Adrian Hunter
Date: Fri Jan 20 2023 - 07:35:31 EST


The code expects non-zero plt_entry_size. Check it and add a debug
message to print if it is zero.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/symbol-elf.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 4605680a22a3..c6a4e6c73990 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -323,30 +323,33 @@ static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
return demangled;
}

-static void get_plt_sizes(GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
+static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
u64 *plt_header_size, u64 *plt_entry_size)
{
switch (ehdr->e_machine) {
case EM_ARM:
*plt_header_size = 20;
*plt_entry_size = 12;
- return;
+ return true;
case EM_AARCH64:
*plt_header_size = 32;
*plt_entry_size = 16;
- return;
+ return true;
case EM_SPARC:
*plt_header_size = 48;
*plt_entry_size = 12;
- return;
+ return true;
case EM_SPARCV9:
*plt_header_size = 128;
*plt_entry_size = 32;
- return;
+ return true;
default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
*plt_header_size = shdr_plt->sh_entsize;
*plt_entry_size = shdr_plt->sh_entsize;
- return;
+ if (*plt_entry_size)
+ return true;
+ pr_debug("Missing PLT entry size for %s\n", dso->long_name);
+ return false;
}
}

@@ -438,7 +441,8 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)

nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
plt_offset = shdr_plt.sh_offset;
- get_plt_sizes(&ehdr, &shdr_plt, &plt_header_size, &plt_entry_size);
+ if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))
+ return 0;
plt_offset += plt_header_size;

if (shdr_rel_plt.sh_type == SHT_RELA) {
--
2.34.1