All of lore.kernel.org
 help / color / mirror / Atom feed
From: Kalesh Singh <kaleshsingh@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org,
	samitolvanen@google.com, ndesaulniers@google.com,
	kernel-team@android.com, Kalesh Singh <kaleshsingh@google.com>,
	kernel test robot <lkp@intel.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3] tracing/cfi: Fix cmp_entries_* functions signature mismatch
Date: Wed, 13 Oct 2021 21:52:17 -0700	[thread overview]
Message-ID: <20211014045217.3265162-1-kaleshsingh@google.com> (raw)

If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
the kernel to panic due to failed CFI check.

    1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
    2. cat events/sched/sched_switch/hist
    3. kernel panics on attempting to read hist

This happens because the sort() function expects a generic
int (*)(const void *, const void *) pointer for the compare function.
To prevent this CFI failure, change tracing map cmp_entries_* function
signatures to match this.

Also, fix the build error reported by the kernel test robot [1].

[1] https://lore.kernel.org/r/202110141140.zzi4dRh4-lkp@intel.com/

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reported-by: kernel test robot <lkp@intel.com>
---
Changes in v3:
  - Fix build error, reported by kernel test robot

Changes in v2:
  - Code style clean up, per Steve
  - Commit message typo fix, per Steve


 kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
index d6bddb157ef2..39bb56d2dcbe 100644
--- a/kernel/trace/tracing_map.c
+++ b/kernel/trace/tracing_map.c
@@ -834,29 +834,35 @@ int tracing_map_init(struct tracing_map *map)
 	return err;
 }
 
-static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
-			   const struct tracing_map_sort_entry **b)
+static int cmp_entries_dup(const void *A, const void *B)
 {
+	const struct tracing_map_sort_entry *a, *b;
 	int ret = 0;
 
-	if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
+	a = *(const struct tracing_map_sort_entry **)A;
+	b = *(const struct tracing_map_sort_entry **)B;
+
+	if (memcmp(a->key, b->key, a->elt->map->key_size))
 		ret = 1;
 
 	return ret;
 }
 
-static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
-			   const struct tracing_map_sort_entry **b)
+static int cmp_entries_sum(const void *A, const void *B)
 {
 	const struct tracing_map_elt *elt_a, *elt_b;
+	const struct tracing_map_sort_entry *a, *b;
 	struct tracing_map_sort_key *sort_key;
 	struct tracing_map_field *field;
 	tracing_map_cmp_fn_t cmp_fn;
 	void *val_a, *val_b;
 	int ret = 0;
 
-	elt_a = (*a)->elt;
-	elt_b = (*b)->elt;
+	a = *(const struct tracing_map_sort_entry **)A;
+	b = *(const struct tracing_map_sort_entry **)B;
+
+	elt_a = a->elt;
+	elt_b = b->elt;
 
 	sort_key = &elt_a->map->sort_key;
 
@@ -873,18 +879,21 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
 	return ret;
 }
 
-static int cmp_entries_key(const struct tracing_map_sort_entry **a,
-			   const struct tracing_map_sort_entry **b)
+static int cmp_entries_key(const void *A, const void *B)
 {
 	const struct tracing_map_elt *elt_a, *elt_b;
+	const struct tracing_map_sort_entry *a, *b;
 	struct tracing_map_sort_key *sort_key;
 	struct tracing_map_field *field;
 	tracing_map_cmp_fn_t cmp_fn;
 	void *val_a, *val_b;
 	int ret = 0;
 
-	elt_a = (*a)->elt;
-	elt_b = (*b)->elt;
+	a = *(const struct tracing_map_sort_entry **)A;
+	b = *(const struct tracing_map_sort_entry **)B;
+
+	elt_a = a->elt;
+	elt_b = b->elt;
 
 	sort_key = &elt_a->map->sort_key;
 
@@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
 			   struct tracing_map_sort_key *primary_key,
 			   struct tracing_map_sort_key *secondary_key)
 {
-	int (*primary_fn)(const struct tracing_map_sort_entry **,
-			  const struct tracing_map_sort_entry **);
-	int (*secondary_fn)(const struct tracing_map_sort_entry **,
-			    const struct tracing_map_sort_entry **);
+	int (*primary_fn)(const void *, const void *);
+	int (*secondary_fn)(const void *, const void *);
 	unsigned i, start = 0, n_sub = 1;
 
 	if (is_key(map, primary_key->field_idx))
@@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
 			     unsigned int n_sort_keys,
 			     struct tracing_map_sort_entry ***sort_entries)
 {
-	int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
-			      const struct tracing_map_sort_entry **);
+	int (*cmp_entries_fn)(const void *, const void *);
 	struct tracing_map_sort_entry *sort_entry, **entries;
 	int i, n_entries, ret;
 

base-commit: 348949d9a4440abdab3b1dc99a9bb660e8c7da7c
-- 
2.33.0.1079.g6e70778dc9-goog


                 reply	other threads:[~2021-10-14  4:52 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

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=20211014045217.3265162-1-kaleshsingh@google.com \
    --to=kaleshsingh@google.com \
    --cc=hridya@google.com \
    --cc=kernel-team@android.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lkp@intel.com \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=ndesaulniers@google.com \
    --cc=rostedt@goodmis.org \
    --cc=samitolvanen@google.com \
    --cc=surenb@google.com \
    --subject='Re: [PATCH v3] tracing/cfi: Fix cmp_entries_* functions signature mismatch' \
    /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

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.