Building the Linux kernel with Clang and LLVM
 help / color / mirror / Atom feed
From: Ian Rogers <irogers@google.com>
To: langfei@huawei.com, Peter Zijlstra <peterz@infradead.org>,
	 Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	 Mark Rutland <mark.rutland@arm.com>,
	 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,  Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	 Kan Liang <kan.liang@linux.intel.com>,
	Nathan Chancellor <nathan@kernel.org>,
	 Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	 Justin Stitt <justinstitt@google.com>,
	James Clark <james.clark@linaro.org>,
	 Chaitanya S Prakash <chaitanyas.prakash@arm.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	 Stephen Brennan <stephen.s.brennan@oracle.com>,
	Howard Chu <howardchu95@gmail.com>,
	 linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	 llvm@lists.linux.dev
Subject: [PATCH v1 1/3] perf dso: Minor refactor to allow Wthread-safety analysis
Date: Mon, 19 May 2025 15:46:43 -0700	[thread overview]
Message-ID: <20250519224645.1810891-1-irogers@google.com> (raw)

The pattern:
```
if (x) {
   lock(...)
}
block1;
if (x) {
   unlock(...)
}
```
defeats clang's -Wthread-safety analysis where it complains of locks
held on one path and not another. Add helper functions for "block1"
then restructure as:
```
if (x) {
   lock(...);
   block1();
   unlock(...);
} else {
   block1();
}
```

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/dso.c | 45 +++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 8619b6eea62d..057fcf4225ac 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1349,6 +1349,16 @@ struct dso *machine__findnew_kernel(struct machine *machine, const char *name,
 	return dso;
 }
 
+static void __dso__set_long_name_id(struct dso *dso, const char *name, bool name_allocated)
+{
+	if (dso__long_name_allocated(dso))
+		free((char *)dso__long_name(dso));
+
+	RC_CHK_ACCESS(dso)->long_name = name;
+	RC_CHK_ACCESS(dso)->long_name_len = strlen(name);
+	dso__set_long_name_allocated(dso, name_allocated);
+}
+
 static void dso__set_long_name_id(struct dso *dso, const char *name, bool name_allocated)
 {
 	struct dsos *dsos = dso__dsos(dso);
@@ -1362,18 +1372,11 @@ static void dso__set_long_name_id(struct dso *dso, const char *name, bool name_a
 		 * renaming the dso.
 		 */
 		down_write(&dsos->lock);
-	}
-
-	if (dso__long_name_allocated(dso))
-		free((char *)dso__long_name(dso));
-
-	RC_CHK_ACCESS(dso)->long_name = name;
-	RC_CHK_ACCESS(dso)->long_name_len = strlen(name);
-	dso__set_long_name_allocated(dso, name_allocated);
-
-	if (dsos) {
+		__dso__set_long_name_id(dso, name, name_allocated);
 		dsos->sorted = false;
 		up_write(&dsos->lock);
+	} else {
+		__dso__set_long_name_id(dso, name, name_allocated);
 	}
 }
 
@@ -1451,6 +1454,16 @@ void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
 	dso__set_long_name_id(dso, name, name_allocated);
 }
 
+static void __dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
+{
+	if (dso__short_name_allocated(dso))
+		free((char *)dso__short_name(dso));
+
+	RC_CHK_ACCESS(dso)->short_name		  = name;
+	RC_CHK_ACCESS(dso)->short_name_len	  = strlen(name);
+	dso__set_short_name_allocated(dso, name_allocated);
+}
+
 void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
 {
 	struct dsos *dsos = dso__dsos(dso);
@@ -1464,17 +1477,11 @@ void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
 		 * renaming the dso.
 		 */
 		down_write(&dsos->lock);
-	}
-	if (dso__short_name_allocated(dso))
-		free((char *)dso__short_name(dso));
-
-	RC_CHK_ACCESS(dso)->short_name		  = name;
-	RC_CHK_ACCESS(dso)->short_name_len	  = strlen(name);
-	dso__set_short_name_allocated(dso, name_allocated);
-
-	if (dsos) {
+		__dso__set_short_name(dso, name, name_allocated);
 		dsos->sorted = false;
 		up_write(&dsos->lock);
+	} else {
+		__dso__set_short_name(dso, name, name_allocated);
 	}
 }
 
-- 
2.49.0.1101.gccaa498523-goog


             reply	other threads:[~2025-05-19 22:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-19 22:46 Ian Rogers [this message]
2025-05-19 22:46 ` [PATCH v1 2/3] perf rwsem: Add thread-safety annotations Ian Rogers
2025-05-19 22:46 ` [PATCH v1 3/3] perf thread: Ensure comm_lock held for comm_list Ian Rogers
2025-05-20 21:17 ` [PATCH v1 1/3] perf dso: Minor refactor to allow Wthread-safety analysis Arnaldo Carvalho de Melo

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=20250519224645.1810891-1-irogers@google.com \
    --to=irogers@google.com \
    --cc=acme@kernel.org \
    --cc=adrian.hunter@intel.com \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=atrajeev@linux.vnet.ibm.com \
    --cc=chaitanyas.prakash@arm.com \
    --cc=howardchu95@gmail.com \
    --cc=james.clark@linaro.org \
    --cc=jolsa@kernel.org \
    --cc=justinstitt@google.com \
    --cc=kan.liang@linux.intel.com \
    --cc=langfei@huawei.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-perf-users@vger.kernel.org \
    --cc=llvm@lists.linux.dev \
    --cc=mark.rutland@arm.com \
    --cc=mingo@redhat.com \
    --cc=morbo@google.com \
    --cc=namhyung@kernel.org \
    --cc=nathan@kernel.org \
    --cc=nick.desaulniers+lkml@gmail.com \
    --cc=peterz@infradead.org \
    --cc=stephen.s.brennan@oracle.com \
    /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