From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Leo Yan <leo.yan@linaro.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>, Ian Rogers <irogers@google.com>
Subject: [PATCH] perf symbol: Fail to read phdr workaround
Date: Sun, 31 Jul 2022 09:49:23 -0700 [thread overview]
Message-ID: <20220731164923.691193-1-irogers@google.com> (raw)
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
next reply other threads:[~2022-07-31 16:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-31 16:49 Ian Rogers [this message]
2022-08-01 1:52 ` [PATCH] perf symbol: Fail to read phdr workaround Leo Yan
[not found] ` <CAP-5=fVSjCQ4jeAeyP5THnQVyXDpKd6Ob33C7PDwFB_6+YSXuw@mail.gmail.com>
2022-08-01 12:38 ` Arnaldo Carvalho de Melo
2022-08-01 13:25 ` Leo Yan
2022-08-01 17:56 ` Arnaldo Carvalho de Melo
2022-08-03 15:25 ` Leo Yan
2022-08-04 0:26 ` Ian Rogers
2022-08-04 1:21 ` Leo Yan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220731164923.691193-1-irogers@google.com \
--to=irogers@google.com \
--cc=acme@kernel.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=eranian@google.com \
--cc=jolsa@kernel.org \
--cc=leo.yan@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).