From: Marco Elver <elver@google.com>
To: elver@google.com, "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexander Potapenko <glider@google.com>,
Boqun Feng <boqun.feng@gmail.com>, Borislav Petkov <bp@alien8.de>,
Dmitry Vyukov <dvyukov@google.com>,
Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>,
kasan-dev@googlegroups.com, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
llvm@lists.linux.dev, x86@kernel.org
Subject: [PATCH v3 08/25] kcsan: Show location access was reordered to
Date: Tue, 30 Nov 2021 12:44:16 +0100 [thread overview]
Message-ID: <20211130114433.2580590-9-elver@google.com> (raw)
In-Reply-To: <20211130114433.2580590-1-elver@google.com>
Also show the location the access was reordered to. An example report:
| ==================================================================
| BUG: KCSAN: data-race in test_kernel_wrong_memorder / test_kernel_wrong_memorder
|
| read-write to 0xffffffffc01e61a8 of 8 bytes by task 2311 on cpu 5:
| test_kernel_wrong_memorder+0x57/0x90
| access_thread+0x99/0xe0
| kthread+0x2ba/0x2f0
| ret_from_fork+0x22/0x30
|
| read-write (reordered) to 0xffffffffc01e61a8 of 8 bytes by task 2310 on cpu 7:
| test_kernel_wrong_memorder+0x57/0x90
| access_thread+0x99/0xe0
| kthread+0x2ba/0x2f0
| ret_from_fork+0x22/0x30
| |
| +-> reordered to: test_kernel_wrong_memorder+0x80/0x90
|
| Reported by Kernel Concurrency Sanitizer on:
| CPU: 7 PID: 2310 Comm: access_thread Not tainted 5.14.0-rc1+ #18
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
| ==================================================================
Signed-off-by: Marco Elver <elver@google.com>
---
kernel/kcsan/report.c | 35 +++++++++++++++++++++++------------
1 file changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
index 1b0e050bdf6a..67794404042a 100644
--- a/kernel/kcsan/report.c
+++ b/kernel/kcsan/report.c
@@ -308,10 +308,12 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries
/*
* Skips to the first entry that matches the function of @ip, and then replaces
- * that entry with @ip, returning the entries to skip.
+ * that entry with @ip, returning the entries to skip with @replaced containing
+ * the replaced entry.
*/
static int
-replace_stack_entry(unsigned long stack_entries[], int num_entries, unsigned long ip)
+replace_stack_entry(unsigned long stack_entries[], int num_entries, unsigned long ip,
+ unsigned long *replaced)
{
unsigned long symbolsize, offset;
unsigned long target_func;
@@ -330,6 +332,7 @@ replace_stack_entry(unsigned long stack_entries[], int num_entries, unsigned lon
func -= offset;
if (func == target_func) {
+ *replaced = stack_entries[skip];
stack_entries[skip] = ip;
return skip;
}
@@ -342,9 +345,10 @@ replace_stack_entry(unsigned long stack_entries[], int num_entries, unsigned lon
}
static int
-sanitize_stack_entries(unsigned long stack_entries[], int num_entries, unsigned long ip)
+sanitize_stack_entries(unsigned long stack_entries[], int num_entries, unsigned long ip,
+ unsigned long *replaced)
{
- return ip ? replace_stack_entry(stack_entries, num_entries, ip) :
+ return ip ? replace_stack_entry(stack_entries, num_entries, ip, replaced) :
get_stack_skipnr(stack_entries, num_entries);
}
@@ -360,6 +364,14 @@ static int sym_strcmp(void *addr1, void *addr2)
return strncmp(buf1, buf2, sizeof(buf1));
}
+static void
+print_stack_trace(unsigned long stack_entries[], int num_entries, unsigned long reordered_to)
+{
+ stack_trace_print(stack_entries, num_entries, 0);
+ if (reordered_to)
+ pr_err(" |\n +-> reordered to: %pS\n", (void *)reordered_to);
+}
+
static void print_verbose_info(struct task_struct *task)
{
if (!task)
@@ -378,10 +390,12 @@ static void print_report(enum kcsan_value_change value_change,
struct other_info *other_info,
u64 old, u64 new, u64 mask)
{
+ unsigned long reordered_to = 0;
unsigned long stack_entries[NUM_STACK_ENTRIES] = { 0 };
int num_stack_entries = stack_trace_save(stack_entries, NUM_STACK_ENTRIES, 1);
- int skipnr = sanitize_stack_entries(stack_entries, num_stack_entries, ai->ip);
+ int skipnr = sanitize_stack_entries(stack_entries, num_stack_entries, ai->ip, &reordered_to);
unsigned long this_frame = stack_entries[skipnr];
+ unsigned long other_reordered_to = 0;
unsigned long other_frame = 0;
int other_skipnr = 0; /* silence uninit warnings */
@@ -394,7 +408,7 @@ static void print_report(enum kcsan_value_change value_change,
if (other_info) {
other_skipnr = sanitize_stack_entries(other_info->stack_entries,
other_info->num_stack_entries,
- other_info->ai.ip);
+ other_info->ai.ip, &other_reordered_to);
other_frame = other_info->stack_entries[other_skipnr];
/* @value_change is only known for the other thread */
@@ -434,10 +448,9 @@ static void print_report(enum kcsan_value_change value_change,
other_info->ai.cpu_id);
/* Print the other thread's stack trace. */
- stack_trace_print(other_info->stack_entries + other_skipnr,
+ print_stack_trace(other_info->stack_entries + other_skipnr,
other_info->num_stack_entries - other_skipnr,
- 0);
-
+ other_reordered_to);
if (IS_ENABLED(CONFIG_KCSAN_VERBOSE))
print_verbose_info(other_info->task);
@@ -451,9 +464,7 @@ static void print_report(enum kcsan_value_change value_change,
get_thread_desc(ai->task_pid), ai->cpu_id);
}
/* Print stack trace of this thread. */
- stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr,
- 0);
-
+ print_stack_trace(stack_entries + skipnr, num_stack_entries - skipnr, reordered_to);
if (IS_ENABLED(CONFIG_KCSAN_VERBOSE))
print_verbose_info(current);
--
2.34.0.rc2.393.gf8c9666880-goog
next prev parent reply other threads:[~2021-11-30 11:45 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-30 11:44 [PATCH v3 00/25] kcsan: Support detecting a subset of missing memory barriers Marco Elver
2021-11-30 11:44 ` [PATCH v3 01/25] kcsan: Refactor reading of instrumented memory Marco Elver
2021-11-30 11:44 ` [PATCH v3 02/25] kcsan: Remove redundant zero-initialization of globals Marco Elver
2021-11-30 11:44 ` [PATCH v3 03/25] kcsan: Avoid checking scoped accesses from nested contexts Marco Elver
2021-11-30 11:44 ` [PATCH v3 04/25] kcsan: Add core support for a subset of weak memory modeling Marco Elver
2021-12-03 8:56 ` Marco Elver
2021-12-03 16:50 ` Paul E. McKenney
2021-12-03 21:08 ` Paul E. McKenney
2021-12-03 23:42 ` Marco Elver
2021-12-03 23:42 ` Paul E. McKenney
2021-12-03 23:45 ` Marco Elver
2021-12-04 1:14 ` Paul E. McKenney
2021-11-30 11:44 ` [PATCH v3 05/25] kcsan: Add core memory barrier instrumentation functions Marco Elver
2021-11-30 11:44 ` [PATCH v3 06/25] kcsan, kbuild: Add option for barrier instrumentation only Marco Elver
2021-11-30 11:44 ` [PATCH v3 07/25] kcsan: Call scoped accesses reordered in reports Marco Elver
2021-11-30 11:44 ` Marco Elver [this message]
2021-12-06 5:03 ` [PATCH v3 08/25] kcsan: Show location access was reordered to Boqun Feng
2021-12-06 7:16 ` Marco Elver
2021-12-06 14:31 ` Boqun Feng
2021-12-06 16:04 ` Marco Elver
2021-12-06 17:16 ` Boqun Feng
2021-12-06 17:38 ` Paul E. McKenney
2021-11-30 11:44 ` [PATCH v3 09/25] kcsan: Document modeling of weak memory Marco Elver
2021-11-30 11:44 ` [PATCH v3 10/25] kcsan: test: Match reordered or normal accesses Marco Elver
2021-11-30 11:44 ` [PATCH v3 11/25] kcsan: test: Add test cases for memory barrier instrumentation Marco Elver
2021-11-30 11:44 ` [PATCH v3 12/25] kcsan: Ignore GCC 11+ warnings about TSan runtime support Marco Elver
2021-11-30 11:44 ` [PATCH v3 13/25] kcsan: selftest: Add test case to check memory barrier instrumentation Marco Elver
2021-11-30 11:44 ` [PATCH v3 14/25] locking/barriers, kcsan: Add instrumentation for barriers Marco Elver
2021-11-30 11:44 ` [PATCH v3 15/25] locking/barriers, kcsan: Support generic instrumentation Marco Elver
2021-11-30 11:44 ` [PATCH v3 16/25] locking/atomics, kcsan: Add instrumentation for barriers Marco Elver
2021-11-30 11:44 ` [PATCH v3 17/25] asm-generic/bitops, " Marco Elver
2021-11-30 11:44 ` [PATCH v3 18/25] x86/barriers, kcsan: Use generic instrumentation for non-smp barriers Marco Elver
2021-11-30 11:44 ` [PATCH v3 19/25] x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() Marco Elver
2021-11-30 11:44 ` [PATCH v3 20/25] mm, kcsan: Enable barrier instrumentation Marco Elver
2021-11-30 11:44 ` [PATCH v3 21/25] sched, kcsan: Enable memory " Marco Elver
2021-11-30 11:44 ` [PATCH v3 22/25] objtool, kcsan: Add memory barrier instrumentation to whitelist Marco Elver
2021-11-30 11:44 ` [PATCH v3 23/25] objtool, kcsan: Remove memory barrier instrumentation from noinstr Marco Elver
2021-11-30 11:44 ` [PATCH v3 24/25] compiler_attributes.h: Add __disable_sanitizer_instrumentation Marco Elver
2021-11-30 11:44 ` [PATCH v3 25/25] kcsan: Support WEAK_MEMORY with Clang where no objtool support exists Marco Elver
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