[PATCHES v8 0/2] perf c2c hardening

[PATCHES v8 0/2] perf c2c hardening

[Arnaldo Carvalho de Melo]

Hi,

	Please consider merging,

Two hardening fixes for perf c2c found by the sashiko-bot AI reviewer.

Patch 1 fixes error masking, OOM, and unchecked caller errors in
hpp_list__parse(): the strdup() return values are now checked, PARSE_LIST
was turned into a function that bails out on any error returned by the
parsing callbacks (including -ENOMEM), and the two callers bailing out
with the newly propagated errors, setup_sort_list() and
setup_output_list(), now break out of their token loops and propagate the
error instead of silently overwriting it on the next iteration.

Patch 2 fixes a format list leak: when c2c_hists__[re]init() fails
partway through, entries registered via perf_hpp_list__column_register()
and perf_hpp_list__register_sort_field() are left on the hpp_list.  The
fix moves cleanup into c2c_hists__init()/c2c_hists__reinit() themselves
so all callers are protected.

This series was developed with AI assistance (Claude:Sonnet 4.6 and
Opencode:mimo-v2.5-free for the changes up to v7; the changes since v7,
including the setup_sort_list()/setup_output_list() -ENOMEM propagation
fix and the c2c_hists__reinit() cleanup amendment, with
Opencode:DeepSeek-V4-Flash-free).

- Arnaldo

Changes since v7 (20260804185830.228763-1-acme@kernel.org):

  Patch 1:
  - Addressed sashiko-bot [Medium] finding: with sort_dimension__add()
    and output_field_add() now propagating -ENOMEM (and other errors),
    the callers setup_sort_list() and setup_output_list() only checked
    for -EINVAL and -ESRCH, so an allocation failure was silently
    overwritten when the next loop iteration ran.  Both callers now break
    out of their token loops on any error and propagate it.

Changes since v6 (20260803180703.194916-1-acme@kernel.org):

  Patch 2:
  - c2c_hists__reinit() has the same leak: it clears the list then calls
    hpp_list__parse(), which can register formats before failing, and
    neither the function nor its callers clean up on failure.  Add the
    same cleanup-on-failure pattern to close this gap.

Changes since v5 (20260803180118.194519-1-acme@kernel.org):

  - The second v5 patch didn't go through, resending the same contents
    as v5.

Changes since v4 (20260803144119.185637-1-acme@kernel.org):

  - Replace %m with str_error_r(-ret) as suggested by sashiko.

Changes since v3 (20260803120452.181273-1-acme@kernel.org):

  - Use 'goto out' to break out from both the switch and the for loop in
    __hpp_list__parse() as noticed by sashiko.

Changes since v2 (20260803011140.179943-1-acme@kernel.org):

  - Added the string.h and stdlib.h missing headers.
  - Addressed sashiko comment on PARSE_LIST, turning it into a function
    and handling all errors returned from _fn().

Changes since v1 (20260802142313.154514-1-acme@kernel.org):

  - Addressed sashiko-bot [Medium] finding: the early exits added by v1
    skip perf_hpp__setup_output_field(), making undetected errors in the
    callers consequential.  Fixed by propagating the error through
    resort_cl_cb() and perf_c2c__report() (hists__iterate_cb() already
    propagated callback return values).
  - Dismissed sashiko-bot [Low] finding (missing string.h/stdlib.h):
    strdup() and free() were already used in this function before this
    patch; string2.h (included at the top of the file) pulls in string.h.
    No new library calls were introduced.
  - Subject updated to reflect the additional caller fixes.

Arnaldo Carvalho de Melo (2):
  perf c2c: Fix error masking, OOM, and unchecked caller errors in hpp_list__parse()
  perf c2c: Clean up registered formats on c2c_hists__init() and c2c_hists__reinit() failure

 tools/perf/builtin-c2c.c | 105 ++++++++++++++++++++++++++++++----------
 tools/perf/util/sort.c   |  76 ++++++++++++++++++++++-------
 2 files changed, 130 insertions(+), 52 deletions(-)

---


Arnaldo Carvalho de Melo (2):
  perf c2c: Fix error masking, OOM, and unchecked caller errors in
    hpp_list__parse()
  perf c2c: Clean up registered formats on c2c_hists__init() and
    c2c_hists__reinit() failure

 tools/perf/builtin-c2c.c | 106 ++++++++++++++++++++++++++++-----------
 tools/perf/util/sort.c   |  76 +++++++++++++++++++---------
 2 files changed, 130 insertions(+), 52 deletions(-)

-- 
2.55.0

[PATCH 1/2] perf c2c: Fix error masking, OOM, and unchecked caller errors in hpp_list__parse()

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

hpp_list__parse() has three bugs:

1. The PARSE_LIST macro resets ret = 0 at the start of each invocation,
   so an error from output parsing is silently overwritten when the sort
   parsing block runs.  The function returns success with partially
   initialized state.

2. When the caller passes a non-NULL output_ or sort_ string, but
   strdup() returns NULL due to OOM, NULL is passed to PARSE_LIST which
   treats it as empty input (the "if (!_list) break" branch).  No error
   is returned.

3. When the called _fn function fails and returns something other than
   -ESRCH or -EINVAL (-ENOMEM, for instance) it was not bailing out of
   the strtok loop.

Fix them by checking strdup() return values before proceeding and adding
a cleanup label so that ret from each PARSE_LIST call is checked before
the next runs, preserving the first error.

The early exits now skip perf_hpp__setup_output_field(), which means
c2c_hists__reinit() can return a non-zero value in cases that previously
always succeeded silently.  Both callers discarded its return:
resort_cl_cb() continued into hists__collapse_resort() on a broken list,
and perf_c2c__report() proceeded with uninitialised hists.  Fix the full
chain: check and propagate the error in resort_cl_cb() -- hists__iterate_cb()
already stops iteration and returns the callback error -- and check both
c2c_hists__reinit() and hists__iterate_cb() in perf_c2c__report().

Also turn PARSE_LIST into a function, using a switch to catch other
errors, converting the called functions to return an appropriate errno
instead of -1 on failure.

Also make the two callers that iterate sort_dimension__add() and
output_field_add() handle the newly propagated errors: setup_sort_list()
and setup_output_list() only checked for -EINVAL and -ESRCH, so an
-ENOMEM from a failed allocation was silently overwritten by the next
loop iteration.  Break out of the loop and propagate any other error.

The hpp_list__parse() fixes were developed with AI assistance from
Claude:claude-sonnet-4.6, and the setup_sort_list()/setup_output_list()
caller fixes with AI assistance from Opencode:mimo-v2.5-free and
Opencode:DeepSeek-V4-Flash-free.

Fixes: 2d388bd0c9d3 ("perf c2c report: Add stdio output support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-sonnet-4.6
Assisted-by: Opencode:mimo-v2.5-free
Assisted-by: Opencode:DeepSeek-V4-Flash-free
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-c2c.c | 85 ++++++++++++++++++++++++++++------------
 tools/perf/util/sort.c   | 76 +++++++++++++++++++++++------------
 2 files changed, 112 insertions(+), 49 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index c9584dbedf77afe8..160b82694d391c50 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -12,11 +12,14 @@
  */
 #include <errno.h>
 #include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include <asm/bug.h>
 #include <linux/compiler.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
+#include <linux/string.h>
 #include <linux/stringify.h>
 #include <linux/zalloc.h>
 #include <sys/param.h>
@@ -2063,26 +2066,38 @@ static int c2c_hists__init_sort(struct perf_hpp_list *hpp_list, char *name, stru
 	return 0;
 }
 
-#define PARSE_LIST(_list, _fn)							\
-	do {									\
-		char *tmp, *tok;						\
-		ret = 0;							\
-										\
-		if (!_list)							\
-			break;							\
-										\
-		for (tok = strtok_r((char *)_list, ", ", &tmp);			\
-				tok; tok = strtok_r(NULL, ", ", &tmp)) {	\
-			ret = _fn(hpp_list, tok, env);				\
-			if (ret == -EINVAL) {					\
-				pr_err("Invalid --fields key: `%s'", tok);	\
-				break;						\
-			} else if (ret == -ESRCH) {				\
-				pr_err("Unknown --fields key: `%s'", tok);	\
-				break;						\
-			}							\
-		}								\
-	} while (0)
+static int __hpp_list__parse(struct perf_hpp_list *hpp_list, char *_list, struct perf_env *env,
+			     int (*_fn)(struct perf_hpp_list *hpp_list, char *name, struct perf_env *env))
+{
+	char *tmp, *tok;
+	int ret = 0;
+
+	if (!_list)
+		return 0;
+
+	for (tok = strtok_r(_list, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
+		ret = _fn(hpp_list, tok, env);
+		switch (ret) {
+		case 0:
+			continue;
+		case -EINVAL:
+			pr_err("Invalid --fields key: `%s'", tok);
+			goto out;
+		case -ESRCH:
+			pr_err("Unknown --fields key: `%s'", tok);
+			goto out;
+		default: {
+			char buf[STRERR_BUFSIZE];
+
+			pr_err("%s for --fields key: `%s'",
+			       str_error_r(-ret, buf, sizeof(buf)), tok);
+			goto out;
+		}
+		}
+	}
+out:
+	return ret;
+}
 
 static int hpp_list__parse(struct perf_hpp_list *hpp_list,
 			   const char *output_,
@@ -2093,8 +2108,18 @@ static int hpp_list__parse(struct perf_hpp_list *hpp_list,
 	char *sort   = sort_   ? strdup(sort_) : NULL;
 	int ret;
 
-	PARSE_LIST(output, c2c_hists__init_output);
-	PARSE_LIST(sort,   c2c_hists__init_sort);
+	/* strdup() returns NULL on OOM, don't silently treat as empty */
+	if ((output_ && !output) || (sort_ && !sort)) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = __hpp_list__parse(hpp_list, output, env, c2c_hists__init_output);
+	if (ret)
+		goto out;
+	ret = __hpp_list__parse(hpp_list, sort, env, c2c_hists__init_sort);
+	if (ret)
+		goto out;
 
 	/* copy sort keys to output fields */
 	perf_hpp__setup_output_field(hpp_list);
@@ -2111,6 +2136,7 @@ static int hpp_list__parse(struct perf_hpp_list *hpp_list,
 	perf_hpp__append_sort_keys(&hists->list);
 #endif
 
+out:
 	free(output);
 	free(sort);
 	return ret;
@@ -2281,6 +2307,7 @@ static int resort_cl_cb(struct hist_entry *he, void *arg)
 	struct c2c_hist_entry *c2c_he;
 	struct c2c_hists *c2c_hists;
 	bool display = he__display(he, &c2c.shared_clines_stats);
+	int ret;
 
 	c2c_he = container_of(he, struct c2c_hist_entry, he);
 	c2c_hists = c2c_he->hists;
@@ -2291,7 +2318,9 @@ static int resort_cl_cb(struct hist_entry *he, void *arg)
 		c2c_he->cacheline_idx = idx++;
 		calc_width(c2c_he);
 
-		c2c_hists__reinit(c2c_hists, c2c.cl_output, c2c.cl_resort, env);
+		ret = c2c_hists__reinit(c2c_hists, c2c.cl_output, c2c.cl_resort, env);
+		if (ret)
+			return ret;
 
 		hists__collapse_resort(&c2c_hists->hists, NULL);
 		hists__output_resort_cb(&c2c_hists->hists, NULL, filter_cb);
@@ -3356,13 +3385,19 @@ static int perf_c2c__report(int argc, const char **argv)
 	else if (c2c.display == DISPLAY_SNP_PEER)
 		sort_str = "tot_peer";
 
-	c2c_hists__reinit(&c2c.hists, output_str, sort_str, perf_session__env(session));
+	err = c2c_hists__reinit(&c2c.hists, output_str, sort_str, perf_session__env(session));
+	if (err) {
+		pr_err("Failed to reinitialize hists\n");
+		goto out_mem2node;
+	}
 
 	ui_progress__init(&prog, c2c.hists.hists.nr_entries, "Sorting...");
 
 	hists__collapse_resort(&c2c.hists.hists, NULL);
 	hists__output_resort_cb(&c2c.hists.hists, &prog, resort_shared_cl_cb);
-	hists__iterate_cb(&c2c.hists.hists, resort_cl_cb, perf_session__env(session));
+	err = hists__iterate_cb(&c2c.hists.hists, resort_cl_cb, perf_session__env(session));
+	if (err)
+		goto out_mem2node;
 
 	ui_progress__finish();
 
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index dcf9189786f8aeba..58638ec9ae0ede7f 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -3105,7 +3105,7 @@ static int __sort_dimension__add_hpp_sort(struct sort_dimension *sd,
 	struct hpp_sort_entry *hse = __sort_dimension__alloc_hpp(sd, level);
 
 	if (hse == NULL)
-		return -1;
+		return -ENOMEM;
 
 	perf_hpp_list__register_sort_field(list, &hse->hpp);
 	return 0;
@@ -3118,7 +3118,7 @@ static int __sort_dimension__add_hpp_output(struct sort_dimension *sd,
 	struct hpp_sort_entry *hse = __sort_dimension__alloc_hpp(sd, level);
 
 	if (hse == NULL)
-		return -1;
+		return -ENOMEM;
 
 	perf_hpp_list__column_register(list, &hse->hpp);
 	return 0;
@@ -3742,14 +3742,18 @@ static int __sort_dimension__add(struct sort_dimension *sd,
 				 struct perf_hpp_list *list,
 				 int level)
 {
+	int ret;
+
 	if (sd->taken)
 		return 0;
 
-	if (__sort_dimension__add_hpp_sort(sd, list, level) < 0)
-		return -1;
+	ret = __sort_dimension__add_hpp_sort(sd, list, level);
+	if (ret < 0)
+		return ret;
 
-	if (__sort_dimension__update(sd, list) < 0)
-		return -1;
+	ret = __sort_dimension__update(sd, list);
+	if (ret < 0)
+		return ret;
 
 	sd->taken = 1;
 
@@ -3767,7 +3771,7 @@ static int __hpp_dimension__add(struct hpp_dimension *hd,
 
 	fmt = __hpp_dimension__alloc_hpp(hd, level);
 	if (!fmt)
-		return -1;
+		return -ENOMEM;
 
 	hd->taken = 1;
 	hd->was_taken = 1;
@@ -3779,14 +3783,18 @@ static int __sort_dimension__add_output(struct perf_hpp_list *list,
 					struct sort_dimension *sd,
 					int level)
 {
+	int ret;
+
 	if (sd->taken)
 		return 0;
 
-	if (__sort_dimension__add_hpp_output(sd, list, level) < 0)
-		return -1;
+	ret = __sort_dimension__add_hpp_output(sd, list, level);
+	if (ret < 0)
+		return ret;
 
-	if (__sort_dimension__update(sd, list) < 0)
-		return -1;
+	ret = __sort_dimension__update(sd, list);
+	if (ret < 0)
+		return ret;
 
 	sd->taken = 1;
 	return 0;
@@ -3803,7 +3811,7 @@ static int __hpp_dimension__add_output(struct perf_hpp_list *list,
 
 	fmt = __hpp_dimension__alloc_hpp(hd, level);
 	if (!fmt)
-		return -1;
+		return -ENOMEM;
 
 	hd->taken = 1;
 	perf_hpp_list__column_register(list, fmt);
@@ -3869,8 +3877,7 @@ int sort_dimension__add(struct perf_hpp_list *list, const char *tok,
 				    strlen(tok)))
 			return -EINVAL;
 
-		__sort_dimension__add(sd, list, level);
-		return 0;
+		return __sort_dimension__add(sd, list, level);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(memory_sort_dimensions); i++) {
@@ -3882,8 +3889,7 @@ int sort_dimension__add(struct perf_hpp_list *list, const char *tok,
 		if (sort__mode != SORT_MODE__MEMORY)
 			return -EINVAL;
 
-		__sort_dimension__add(sd, list, level);
-		return 0;
+		return __sort_dimension__add(sd, list, level);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(hpp_sort_dimensions); i++) {
@@ -3973,15 +3979,25 @@ static int setup_sort_list(struct perf_hpp_list *list, char *str,
 			}
 
 			ret = sort_dimension__add(list, tok, evlist, env, level);
-			if (ret == -EINVAL) {
+			switch (ret) {
+			case 0:
+				break;
+			case -EINVAL:
 				if (!cacheline_size() && !strncasecmp(tok, "dcacheline", strlen(tok)))
 					ui__error("The \"dcacheline\" --sort key needs to know the cacheline size and it couldn't be determined on this system");
 				else
 					ui__error("Invalid --sort key: `%s'", tok);
-				break;
-			} else if (ret == -ESRCH) {
+				goto out;
+			case -ESRCH:
 				ui__error("Unknown --sort key: `%s'", tok);
-				break;
+				goto out;
+			default: {
+				char buf[STRERR_BUFSIZE];
+
+				ui__error("%s for --sort key: `%s'",
+					  str_error_r(-ret, buf, sizeof(buf)), tok);
+				goto out;
+			}
 			}
 			prev_level = level;
 		}
@@ -3989,6 +4005,7 @@ static int setup_sort_list(struct perf_hpp_list *list, char *str,
 		level = next_level;
 	} while (tmp);
 
+out:
 	return ret;
 }
 
@@ -4315,15 +4332,26 @@ static int setup_output_list(struct perf_hpp_list *list, char *str)
 	for (tok = strtok_r(str, ", ", &tmp);
 			tok; tok = strtok_r(NULL, ", ", &tmp)) {
 		ret = output_field_add(list, tok, &level);
-		if (ret == -EINVAL) {
-			ui__error("Invalid --fields key: `%s'", tok);
+		switch (ret) {
+		case 0:
 			break;
-		} else if (ret == -ESRCH) {
+		case -EINVAL:
+			ui__error("Invalid --fields key: `%s'", tok);
+			goto out;
+		case -ESRCH:
 			ui__error("Unknown --fields key: `%s'", tok);
-			break;
+			goto out;
+		default: {
+			char buf[STRERR_BUFSIZE];
+
+			ui__error("%s for --fields key: `%s'",
+				  str_error_r(-ret, buf, sizeof(buf)), tok);
+			goto out;
+		}
 		}
 	}
 
+out:
 	return ret;
 }
 
-- 
2.55.0

[PATCH 2/2] perf c2c: Clean up registered formats on c2c_hists__init() and c2c_hists__reinit() failure

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

When c2c_hists__init() or c2c_hists__reinit() calls hpp_list__parse()
and it fails partway through, format structures registered via
perf_hpp_list__column_register() and perf_hpp_list__register_sort_field()
are left on the hpp_list.

In c2c_hists__init(), only one of the callers, c2c_he__alloc_hists(),
handled this with perf_hpp__reset_output_field(), while perf_c2c_report()
did not, leaking the partially registered entries.

In c2c_hists__reinit(), neither perf_c2c_report() nor resort_cl_cb()
clean up on failure.

Fix by adding cleanup inside both functions themselves, so all callers
are protected, and remove the now redundant reset in c2c_he__alloc_hists().

Fixes: 78b275437873 ("perf c2c report: Add sample processing")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Assisted-by: Opencode:mimo-v2.5-free
Assisted-by: Opencode:DeepSeek-V4-Flash-free
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-c2c.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 160b82694d391c50..bc16a57e092742ad 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -229,7 +229,6 @@ he__get_c2c_hists(struct hist_entry *he,
 
 	ret = c2c_hists__init(hists, sort, nr_header_lines, env);
 	if (ret) {
-		perf_hpp__reset_output_field(&hists->list);
 		c2c_he->hists = NULL;
 		free(hists);
 		return NULL;
@@ -2147,6 +2146,8 @@ static int c2c_hists__init(struct c2c_hists *hists,
 			   int nr_header_lines,
 			   struct perf_env *env)
 {
+	int ret;
+
 	__hists__init(&hists->hists, &hists->list);
 
 	/*
@@ -2159,7 +2160,13 @@ static int c2c_hists__init(struct c2c_hists *hists,
 	/* Overload number of header lines.*/
 	hists->list.nr_header_lines = nr_header_lines;
 
-	return hpp_list__parse(&hists->list, /*output=*/NULL, sort, env);
+	ret = hpp_list__parse(&hists->list, /*output=*/NULL, sort, env);
+
+	/* Unregister any formats added before the failure point */
+	if (ret)
+		perf_hpp__reset_output_field(&hists->list);
+
+	return ret;
 }
 
 static int c2c_hists__reinit(struct c2c_hists *c2c_hists,
@@ -2167,8 +2174,16 @@ static int c2c_hists__reinit(struct c2c_hists *c2c_hists,
 			     const char *sort,
 			     struct perf_env *env)
 {
+	int ret;
+
 	perf_hpp__reset_output_field(&c2c_hists->list);
-	return hpp_list__parse(&c2c_hists->list, output, sort, env);
+	ret = hpp_list__parse(&c2c_hists->list, output, sort, env);
+
+	/* Unregister any formats added before the failure point */
+	if (ret)
+		perf_hpp__reset_output_field(&c2c_hists->list);
+
+	return ret;
 }
 
 #define DISPLAY_LINE_LIMIT  0.001
-- 
2.55.0

Re: [PATCHES v8 0/2] perf c2c hardening

[Arnaldo Carvalho de Melo]

On Wed, Aug 05, 2026 at 12:10:41PM -0300, Arnaldo Carvalho de Melo wrote:
> Hi,
 
> 	Please consider merging,
 
> Two hardening fixes for perf c2c found by the sashiko-bot AI reviewer.

This short series is finally completely Sashiko clean:

https://sashiko.dev/#/patchset/20260805151043.237233-1-acme%40kernel.org

- Arnaldo

Re: [PATCHES v8 0/2] perf c2c hardening

[Ian Rogers]

On Wed, Aug 5, 2026 at 9:33 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>
> On Wed, Aug 05, 2026 at 12:10:41PM -0300, Arnaldo Carvalho de Melo wrote:
> > Hi,
>
> >       Please consider merging,
>
> > Two hardening fixes for perf c2c found by the sashiko-bot AI reviewer.
>
> This short series is finally completely Sashiko clean:
>
> https://sashiko.dev/#/patchset/20260805151043.237233-1-acme%40kernel.org

With:
https://github.com/sashiko-dev/sashiko/pull/363
I thought we'd start getting positive emails. Perhaps we're waiting
for the server to rebuild or reboot.

Thanks,
Ian

> - Arnaldo

Re: [PATCH 1/2] perf c2c: Fix error masking, OOM, and unchecked caller errors in hpp_list__parse()

[Ian Rogers]

On Wed, Aug 5, 2026 at 8:11 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> hpp_list__parse() has three bugs:
>
> 1. The PARSE_LIST macro resets ret = 0 at the start of each invocation,
>    so an error from output parsing is silently overwritten when the sort
>    parsing block runs.  The function returns success with partially
>    initialized state.
>
> 2. When the caller passes a non-NULL output_ or sort_ string, but
>    strdup() returns NULL due to OOM, NULL is passed to PARSE_LIST which
>    treats it as empty input (the "if (!_list) break" branch).  No error
>    is returned.
>
> 3. When the called _fn function fails and returns something other than
>    -ESRCH or -EINVAL (-ENOMEM, for instance) it was not bailing out of
>    the strtok loop.
>
> Fix them by checking strdup() return values before proceeding and adding
> a cleanup label so that ret from each PARSE_LIST call is checked before
> the next runs, preserving the first error.
>
> The early exits now skip perf_hpp__setup_output_field(), which means
> c2c_hists__reinit() can return a non-zero value in cases that previously
> always succeeded silently.  Both callers discarded its return:
> resort_cl_cb() continued into hists__collapse_resort() on a broken list,
> and perf_c2c__report() proceeded with uninitialised hists.  Fix the full
> chain: check and propagate the error in resort_cl_cb() -- hists__iterate_cb()
> already stops iteration and returns the callback error -- and check both
> c2c_hists__reinit() and hists__iterate_cb() in perf_c2c__report().
>
> Also turn PARSE_LIST into a function, using a switch to catch other
> errors, converting the called functions to return an appropriate errno
> instead of -1 on failure.
>
> Also make the two callers that iterate sort_dimension__add() and
> output_field_add() handle the newly propagated errors: setup_sort_list()
> and setup_output_list() only checked for -EINVAL and -ESRCH, so an
> -ENOMEM from a failed allocation was silently overwritten by the next
> loop iteration.  Break out of the loop and propagate any other error.
>
> The hpp_list__parse() fixes were developed with AI assistance from
> Claude:claude-sonnet-4.6, and the setup_sort_list()/setup_output_list()
> caller fixes with AI assistance from Opencode:mimo-v2.5-free and
> Opencode:DeepSeek-V4-Flash-free.
>
> Fixes: 2d388bd0c9d3 ("perf c2c report: Add stdio output support")
> Reported-by: sashiko-bot <sashiko-bot@kernel.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Assisted-by: Claude:claude-sonnet-4.6
> Assisted-by: Opencode:mimo-v2.5-free
> Assisted-by: Opencode:DeepSeek-V4-Flash-free
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/builtin-c2c.c | 85 ++++++++++++++++++++++++++++------------
>  tools/perf/util/sort.c   | 76 +++++++++++++++++++++++------------
>  2 files changed, 112 insertions(+), 49 deletions(-)
>
> diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> index c9584dbedf77afe8..160b82694d391c50 100644
> --- a/tools/perf/builtin-c2c.c
> +++ b/tools/perf/builtin-c2c.c
> @@ -12,11 +12,14 @@
>   */
>  #include <errno.h>
>  #include <inttypes.h>
> +#include <stdlib.h>
> +#include <string.h>
>
>  #include <asm/bug.h>
>  #include <linux/compiler.h>
>  #include <linux/err.h>
>  #include <linux/kernel.h>
> +#include <linux/string.h>
>  #include <linux/stringify.h>
>  #include <linux/zalloc.h>
>  #include <sys/param.h>
> @@ -2063,26 +2066,38 @@ static int c2c_hists__init_sort(struct perf_hpp_list *hpp_list, char *name, stru
>         return 0;
>  }
>
> -#define PARSE_LIST(_list, _fn)                                                 \
> -       do {                                                                    \
> -               char *tmp, *tok;                                                \
> -               ret = 0;                                                        \
> -                                                                               \
> -               if (!_list)                                                     \
> -                       break;                                                  \
> -                                                                               \
> -               for (tok = strtok_r((char *)_list, ", ", &tmp);                 \
> -                               tok; tok = strtok_r(NULL, ", ", &tmp)) {        \
> -                       ret = _fn(hpp_list, tok, env);                          \
> -                       if (ret == -EINVAL) {                                   \
> -                               pr_err("Invalid --fields key: `%s'", tok);      \
> -                               break;                                          \
> -                       } else if (ret == -ESRCH) {                             \
> -                               pr_err("Unknown --fields key: `%s'", tok);      \
> -                               break;                                          \
> -                       }                                                       \
> -               }                                                               \
> -       } while (0)
> +static int __hpp_list__parse(struct perf_hpp_list *hpp_list, char *_list, struct perf_env *env,
> +                            int (*_fn)(struct perf_hpp_list *hpp_list, char *name, struct perf_env *env))
> +{
> +       char *tmp, *tok;
> +       int ret = 0;
> +
> +       if (!_list)
> +               return 0;
> +
> +       for (tok = strtok_r(_list, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
> +               ret = _fn(hpp_list, tok, env);
> +               switch (ret) {
> +               case 0:
> +                       continue;
> +               case -EINVAL:
> +                       pr_err("Invalid --fields key: `%s'", tok);
> +                       goto out;
> +               case -ESRCH:
> +                       pr_err("Unknown --fields key: `%s'", tok);
> +                       goto out;
> +               default: {
> +                       char buf[STRERR_BUFSIZE];
> +
> +                       pr_err("%s for --fields key: `%s'",
> +                              str_error_r(-ret, buf, sizeof(buf)), tok);
> +                       goto out;
> +               }
> +               }
> +       }
> +out:
> +       return ret;
> +}
>
>  static int hpp_list__parse(struct perf_hpp_list *hpp_list,
>                            const char *output_,
> @@ -2093,8 +2108,18 @@ static int hpp_list__parse(struct perf_hpp_list *hpp_list,
>         char *sort   = sort_   ? strdup(sort_) : NULL;
>         int ret;
>
> -       PARSE_LIST(output, c2c_hists__init_output);
> -       PARSE_LIST(sort,   c2c_hists__init_sort);
> +       /* strdup() returns NULL on OOM, don't silently treat as empty */
> +       if ((output_ && !output) || (sort_ && !sort)) {
> +               ret = -ENOMEM;
> +               goto out;
> +       }
> +
> +       ret = __hpp_list__parse(hpp_list, output, env, c2c_hists__init_output);
> +       if (ret)
> +               goto out;
> +       ret = __hpp_list__parse(hpp_list, sort, env, c2c_hists__init_sort);
> +       if (ret)
> +               goto out;
>
>         /* copy sort keys to output fields */
>         perf_hpp__setup_output_field(hpp_list);
> @@ -2111,6 +2136,7 @@ static int hpp_list__parse(struct perf_hpp_list *hpp_list,
>         perf_hpp__append_sort_keys(&hists->list);
>  #endif
>
> +out:
>         free(output);
>         free(sort);
>         return ret;
> @@ -2281,6 +2307,7 @@ static int resort_cl_cb(struct hist_entry *he, void *arg)
>         struct c2c_hist_entry *c2c_he;
>         struct c2c_hists *c2c_hists;
>         bool display = he__display(he, &c2c.shared_clines_stats);
> +       int ret;
>
>         c2c_he = container_of(he, struct c2c_hist_entry, he);
>         c2c_hists = c2c_he->hists;
> @@ -2291,7 +2318,9 @@ static int resort_cl_cb(struct hist_entry *he, void *arg)
>                 c2c_he->cacheline_idx = idx++;
>                 calc_width(c2c_he);
>
> -               c2c_hists__reinit(c2c_hists, c2c.cl_output, c2c.cl_resort, env);
> +               ret = c2c_hists__reinit(c2c_hists, c2c.cl_output, c2c.cl_resort, env);
> +               if (ret)
> +                       return ret;
>
>                 hists__collapse_resort(&c2c_hists->hists, NULL);
>                 hists__output_resort_cb(&c2c_hists->hists, NULL, filter_cb);
> @@ -3356,13 +3385,19 @@ static int perf_c2c__report(int argc, const char **argv)
>         else if (c2c.display == DISPLAY_SNP_PEER)
>                 sort_str = "tot_peer";
>
> -       c2c_hists__reinit(&c2c.hists, output_str, sort_str, perf_session__env(session));
> +       err = c2c_hists__reinit(&c2c.hists, output_str, sort_str, perf_session__env(session));
> +       if (err) {
> +               pr_err("Failed to reinitialize hists\n");
> +               goto out_mem2node;
> +       }
>
>         ui_progress__init(&prog, c2c.hists.hists.nr_entries, "Sorting...");
>
>         hists__collapse_resort(&c2c.hists.hists, NULL);
>         hists__output_resort_cb(&c2c.hists.hists, &prog, resort_shared_cl_cb);
> -       hists__iterate_cb(&c2c.hists.hists, resort_cl_cb, perf_session__env(session));
> +       err = hists__iterate_cb(&c2c.hists.hists, resort_cl_cb, perf_session__env(session));
> +       if (err)
> +               goto out_mem2node;
>
>         ui_progress__finish();
>
> diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> index dcf9189786f8aeba..58638ec9ae0ede7f 100644
> --- a/tools/perf/util/sort.c
> +++ b/tools/perf/util/sort.c
> @@ -3105,7 +3105,7 @@ static int __sort_dimension__add_hpp_sort(struct sort_dimension *sd,
>         struct hpp_sort_entry *hse = __sort_dimension__alloc_hpp(sd, level);
>
>         if (hse == NULL)
> -               return -1;
> +               return -ENOMEM;
>
>         perf_hpp_list__register_sort_field(list, &hse->hpp);
>         return 0;
> @@ -3118,7 +3118,7 @@ static int __sort_dimension__add_hpp_output(struct sort_dimension *sd,
>         struct hpp_sort_entry *hse = __sort_dimension__alloc_hpp(sd, level);
>
>         if (hse == NULL)
> -               return -1;
> +               return -ENOMEM;
>
>         perf_hpp_list__column_register(list, &hse->hpp);
>         return 0;
> @@ -3742,14 +3742,18 @@ static int __sort_dimension__add(struct sort_dimension *sd,
>                                  struct perf_hpp_list *list,
>                                  int level)
>  {
> +       int ret;
> +
>         if (sd->taken)
>                 return 0;
>
> -       if (__sort_dimension__add_hpp_sort(sd, list, level) < 0)
> -               return -1;
> +       ret = __sort_dimension__add_hpp_sort(sd, list, level);
> +       if (ret < 0)
> +               return ret;
>
> -       if (__sort_dimension__update(sd, list) < 0)
> -               return -1;
> +       ret = __sort_dimension__update(sd, list);
> +       if (ret < 0)
> +               return ret;
>
>         sd->taken = 1;
>
> @@ -3767,7 +3771,7 @@ static int __hpp_dimension__add(struct hpp_dimension *hd,
>
>         fmt = __hpp_dimension__alloc_hpp(hd, level);
>         if (!fmt)
> -               return -1;
> +               return -ENOMEM;
>
>         hd->taken = 1;
>         hd->was_taken = 1;
> @@ -3779,14 +3783,18 @@ static int __sort_dimension__add_output(struct perf_hpp_list *list,
>                                         struct sort_dimension *sd,
>                                         int level)
>  {
> +       int ret;
> +
>         if (sd->taken)
>                 return 0;
>
> -       if (__sort_dimension__add_hpp_output(sd, list, level) < 0)
> -               return -1;
> +       ret = __sort_dimension__add_hpp_output(sd, list, level);
> +       if (ret < 0)
> +               return ret;
>
> -       if (__sort_dimension__update(sd, list) < 0)
> -               return -1;
> +       ret = __sort_dimension__update(sd, list);
> +       if (ret < 0)
> +               return ret;
>
>         sd->taken = 1;
>         return 0;
> @@ -3803,7 +3811,7 @@ static int __hpp_dimension__add_output(struct perf_hpp_list *list,
>
>         fmt = __hpp_dimension__alloc_hpp(hd, level);
>         if (!fmt)
> -               return -1;
> +               return -ENOMEM;
>
>         hd->taken = 1;
>         perf_hpp_list__column_register(list, fmt);
> @@ -3869,8 +3877,7 @@ int sort_dimension__add(struct perf_hpp_list *list, const char *tok,
>                                     strlen(tok)))
>                         return -EINVAL;
>
> -               __sort_dimension__add(sd, list, level);
> -               return 0;
> +               return __sort_dimension__add(sd, list, level);
>         }
>
>         for (i = 0; i < ARRAY_SIZE(memory_sort_dimensions); i++) {
> @@ -3882,8 +3889,7 @@ int sort_dimension__add(struct perf_hpp_list *list, const char *tok,
>                 if (sort__mode != SORT_MODE__MEMORY)
>                         return -EINVAL;
>
> -               __sort_dimension__add(sd, list, level);
> -               return 0;
> +               return __sort_dimension__add(sd, list, level);
>         }
>
>         for (i = 0; i < ARRAY_SIZE(hpp_sort_dimensions); i++) {
> @@ -3973,15 +3979,25 @@ static int setup_sort_list(struct perf_hpp_list *list, char *str,
>                         }
>
>                         ret = sort_dimension__add(list, tok, evlist, env, level);
> -                       if (ret == -EINVAL) {
> +                       switch (ret) {
> +                       case 0:
> +                               break;
> +                       case -EINVAL:
>                                 if (!cacheline_size() && !strncasecmp(tok, "dcacheline", strlen(tok)))
>                                         ui__error("The \"dcacheline\" --sort key needs to know the cacheline size and it couldn't be determined on this system");
>                                 else
>                                         ui__error("Invalid --sort key: `%s'", tok);
> -                               break;
> -                       } else if (ret == -ESRCH) {
> +                               goto out;
> +                       case -ESRCH:
>                                 ui__error("Unknown --sort key: `%s'", tok);
> -                               break;
> +                               goto out;
> +                       default: {
> +                               char buf[STRERR_BUFSIZE];
> +
> +                               ui__error("%s for --sort key: `%s'",
> +                                         str_error_r(-ret, buf, sizeof(buf)), tok);
> +                               goto out;
> +                       }
>                         }
>                         prev_level = level;
>                 }
> @@ -3989,6 +4005,7 @@ static int setup_sort_list(struct perf_hpp_list *list, char *str,
>                 level = next_level;
>         } while (tmp);
>
> +out:
>         return ret;
>  }
>
> @@ -4315,15 +4332,26 @@ static int setup_output_list(struct perf_hpp_list *list, char *str)
>         for (tok = strtok_r(str, ", ", &tmp);
>                         tok; tok = strtok_r(NULL, ", ", &tmp)) {
>                 ret = output_field_add(list, tok, &level);
> -               if (ret == -EINVAL) {
> -                       ui__error("Invalid --fields key: `%s'", tok);
> +               switch (ret) {
> +               case 0:
>                         break;
> -               } else if (ret == -ESRCH) {
> +               case -EINVAL:
> +                       ui__error("Invalid --fields key: `%s'", tok);
> +                       goto out;
> +               case -ESRCH:
>                         ui__error("Unknown --fields key: `%s'", tok);
> -                       break;
> +                       goto out;
> +               default: {
> +                       char buf[STRERR_BUFSIZE];
> +
> +                       ui__error("%s for --fields key: `%s'",
> +                                 str_error_r(-ret, buf, sizeof(buf)), tok);
> +                       goto out;
> +               }
>                 }
>         }
>
> +out:
>         return ret;
>  }
>
> --
> 2.55.0
>

Re: [PATCH 2/2] perf c2c: Clean up registered formats on c2c_hists__init() and c2c_hists__reinit() failure

[Ian Rogers]

On Wed, Aug 5, 2026 at 8:11 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> When c2c_hists__init() or c2c_hists__reinit() calls hpp_list__parse()
> and it fails partway through, format structures registered via
> perf_hpp_list__column_register() and perf_hpp_list__register_sort_field()
> are left on the hpp_list.
>
> In c2c_hists__init(), only one of the callers, c2c_he__alloc_hists(),
> handled this with perf_hpp__reset_output_field(), while perf_c2c_report()
> did not, leaking the partially registered entries.
>
> In c2c_hists__reinit(), neither perf_c2c_report() nor resort_cl_cb()
> clean up on failure.
>
> Fix by adding cleanup inside both functions themselves, so all callers
> are protected, and remove the now redundant reset in c2c_he__alloc_hists().
>
> Fixes: 78b275437873 ("perf c2c report: Add sample processing")
> Reported-by: sashiko-bot <sashiko-bot@kernel.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Assisted-by: Claude:claude-opus-4.6
> Assisted-by: Opencode:mimo-v2.5-free
> Assisted-by: Opencode:DeepSeek-V4-Flash-free
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/builtin-c2c.c | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> index 160b82694d391c50..bc16a57e092742ad 100644
> --- a/tools/perf/builtin-c2c.c
> +++ b/tools/perf/builtin-c2c.c
> @@ -229,7 +229,6 @@ he__get_c2c_hists(struct hist_entry *he,
>
>         ret = c2c_hists__init(hists, sort, nr_header_lines, env);
>         if (ret) {
> -               perf_hpp__reset_output_field(&hists->list);
>                 c2c_he->hists = NULL;
>                 free(hists);
>                 return NULL;
> @@ -2147,6 +2146,8 @@ static int c2c_hists__init(struct c2c_hists *hists,
>                            int nr_header_lines,
>                            struct perf_env *env)
>  {
> +       int ret;
> +
>         __hists__init(&hists->hists, &hists->list);
>
>         /*
> @@ -2159,7 +2160,13 @@ static int c2c_hists__init(struct c2c_hists *hists,
>         /* Overload number of header lines.*/
>         hists->list.nr_header_lines = nr_header_lines;
>
> -       return hpp_list__parse(&hists->list, /*output=*/NULL, sort, env);
> +       ret = hpp_list__parse(&hists->list, /*output=*/NULL, sort, env);
> +
> +       /* Unregister any formats added before the failure point */
> +       if (ret)
> +               perf_hpp__reset_output_field(&hists->list);
> +
> +       return ret;
>  }
>
>  static int c2c_hists__reinit(struct c2c_hists *c2c_hists,
> @@ -2167,8 +2174,16 @@ static int c2c_hists__reinit(struct c2c_hists *c2c_hists,
>                              const char *sort,
>                              struct perf_env *env)
>  {
> +       int ret;
> +
>         perf_hpp__reset_output_field(&c2c_hists->list);
> -       return hpp_list__parse(&c2c_hists->list, output, sort, env);
> +       ret = hpp_list__parse(&c2c_hists->list, output, sort, env);
> +
> +       /* Unregister any formats added before the failure point */
> +       if (ret)
> +               perf_hpp__reset_output_field(&c2c_hists->list);
> +
> +       return ret;
>  }
>
>  #define DISPLAY_LINE_LIMIT  0.001
> --
> 2.55.0
>

Re: [PATCHES v8 0/2] perf c2c hardening

[Namhyung Kim]

On Wed, 05 Aug 2026 12:10:41 -0300, Arnaldo Carvalho de Melo wrote:
> 	Please consider merging,
> 
> Two hardening fixes for perf c2c found by the sashiko-bot AI reviewer.
> 
> Patch 1 fixes error masking, OOM, and unchecked caller errors in
> hpp_list__parse(): the strdup() return values are now checked, PARSE_LIST
> was turned into a function that bails out on any error returned by the
> parsing callbacks (including -ENOMEM), and the two callers bailing out
> with the newly propagated errors, setup_sort_list() and
> setup_output_list(), now break out of their token loops and propagate the
> error instead of silently overwriting it on the next iteration.
> 
> [...]
Applied to perf-tools-next, thanks!

Best regards,
Namhyung