From: Pingfan Liu <kernelfans@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Pingfan Liu <kernelfans@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Wang Qing <wangqing@vivo.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Santosh Sivaraj <santosh@fossix.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCHv3 2/4] kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event
Date: Thu, 14 Oct 2021 10:41:53 +0800 [thread overview]
Message-ID: <20211014024155.15253-3-kernelfans@gmail.com> (raw)
In-Reply-To: <20211014024155.15253-1-kernelfans@gmail.com>
hardlockup_detector_event_create() should create perf_event on the
current CPU. Preemption could not get disabled because
perf_event_create_kernel_counter() allocates memory. Instead,
the CPU locality is achieved by processing the code in a per-CPU
bound kthread.
Add a check to prevent mistakes when calling the code in another
code path.
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wang Qing <wangqing@vivo.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Santosh Sivaraj <santosh@fossix.org>
Cc: linux-arm-kernel@lists.infradead.org
To: linux-kernel@vger.kernel.org
---
kernel/watchdog_hld.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 247bf0b1582c..df010df76576 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -165,10 +165,13 @@ static void watchdog_overflow_callback(struct perf_event *event,
static int hardlockup_detector_event_create(void)
{
- unsigned int cpu = smp_processor_id();
+ unsigned int cpu;
struct perf_event_attr *wd_attr;
struct perf_event *evt;
+ /* This function plans to execute in cpu bound kthread */
+ WARN_ON(!is_percpu_thread());
+ cpu = raw_smp_processor_id();
wd_attr = &wd_hw_attr;
wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
--
2.31.1
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WARNING: multiple messages have this Message-ID (diff)
From: Pingfan Liu <kernelfans@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Pingfan Liu <kernelfans@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Wang Qing <wangqing@vivo.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Santosh Sivaraj <santosh@fossix.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCHv3 2/4] kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event
Date: Thu, 14 Oct 2021 10:41:53 +0800 [thread overview]
Message-ID: <20211014024155.15253-3-kernelfans@gmail.com> (raw)
In-Reply-To: <20211014024155.15253-1-kernelfans@gmail.com>
hardlockup_detector_event_create() should create perf_event on the
current CPU. Preemption could not get disabled because
perf_event_create_kernel_counter() allocates memory. Instead,
the CPU locality is achieved by processing the code in a per-CPU
bound kthread.
Add a check to prevent mistakes when calling the code in another
code path.
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wang Qing <wangqing@vivo.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Santosh Sivaraj <santosh@fossix.org>
Cc: linux-arm-kernel@lists.infradead.org
To: linux-kernel@vger.kernel.org
---
kernel/watchdog_hld.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 247bf0b1582c..df010df76576 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -165,10 +165,13 @@ static void watchdog_overflow_callback(struct perf_event *event,
static int hardlockup_detector_event_create(void)
{
- unsigned int cpu = smp_processor_id();
+ unsigned int cpu;
struct perf_event_attr *wd_attr;
struct perf_event *evt;
+ /* This function plans to execute in cpu bound kthread */
+ WARN_ON(!is_percpu_thread());
+ cpu = raw_smp_processor_id();
wd_attr = &wd_hw_attr;
wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
--
2.31.1
next prev parent reply other threads:[~2021-10-14 2:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 2:41 [PATCHv3 0/4] watchdog_hld cleanup and async model for arm64 Pingfan Liu
2021-10-14 2:41 ` Pingfan Liu
2021-10-14 2:41 ` [PATCHv3 1/4] kernel/watchdog: trival cleanups Pingfan Liu
2021-10-14 2:41 ` Pingfan Liu
2021-10-14 2:41 ` Pingfan Liu [this message]
2021-10-14 2:41 ` [PATCHv3 2/4] kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event Pingfan Liu
2021-10-14 2:41 ` [PATCHv3 3/4] kernel/watchdog: Adapt the watchdog_hld interface for async model Pingfan Liu
2021-10-14 2:41 ` Pingfan Liu
2021-10-14 2:41 ` [PATCHv3 4/4] arm64: Enable perf events based hard lockup detector Pingfan Liu
2021-10-14 2:41 ` Pingfan Liu
2021-10-26 5:10 ` kernel test robot
2021-10-26 5:10 ` kernel test robot
2021-10-26 10:20 ` kernel test robot
2021-10-26 10:20 ` kernel test robot
2022-01-17 10:19 ` [PATCHv3 0/4] watchdog_hld cleanup and async model for arm64 Lecopzer Chen
2022-01-17 10:19 ` Lecopzer Chen
2022-01-24 1:02 ` Pingfan Liu
2022-01-24 1:02 ` Pingfan Liu
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