From: Cong Wang <xiyou.wangcong@gmail.com> To: linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, Cong Wang <xiyou.wangcong@gmail.com>, Tony Luck <tony.luck@intel.com>, Borislav Petkov <bp@alien8.de>, Thomas Gleixner <tglx@linutronix.de> Subject: [v2,2/2] ras: close the race condition with timer Date: Tue, 16 Apr 2019 14:33:51 -0700 [thread overview] Message-ID: <20190416213351.28999-2-xiyou.wangcong@gmail.com> (raw) cec_timer_fn() is a timer callback which reads ce_arr.array[] and updates its decay values. Elements could be added to or removed from this global array in parallel, although the array itself will not grow or shrink. del_lru_elem_unlocked() uses FULL_COUNT() as a key to find a right element to remove, which could be affected by the parallel timer. Fix this by converting the timer to a delayed work as suggested by Borislav, to avoid using spinlock. Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector") Cc: Tony Luck <tony.luck@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> --- drivers/ras/cec.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c index a4ff54e50673..5c2040a7389d 100644 --- a/drivers/ras/cec.c +++ b/drivers/ras/cec.c @@ -2,6 +2,7 @@ #include <linux/mm.h> #include <linux/gfp.h> #include <linux/kernel.h> +#include <linux/workqueue.h> #include <asm/mce.h> @@ -131,7 +132,7 @@ static unsigned int count_threshold = COUNT_MASK; #define CEC_TIMER_DEFAULT_INTERVAL 24 * 60 * 60 /* 24 hrs */ #define CEC_TIMER_MIN_INTERVAL 1 * 60 * 60 /* 1h */ #define CEC_TIMER_MAX_INTERVAL 30 * 24 * 60 * 60 /* one month */ -static struct timer_list cec_timer; +static struct delayed_work cec_work; static u64 timer_interval = CEC_TIMER_DEFAULT_INTERVAL; /* @@ -160,20 +161,21 @@ static void do_spring_cleaning(struct ce_array *ca) /* * @interval in seconds */ -static void cec_mod_timer(struct timer_list *t, unsigned long interval) +static void cec_mod_work(unsigned long interval) { unsigned long iv; - iv = interval * HZ + jiffies; - - mod_timer(t, round_jiffies(iv)); + iv = interval * HZ; + mod_delayed_work(system_wq, &cec_work, round_jiffies(iv)); } -static void cec_timer_fn(struct timer_list *unused) +static void cec_work_fn(struct work_struct *work) { + mutex_lock(&ce_mutex); do_spring_cleaning(&ce_arr); + mutex_unlock(&ce_mutex); - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(timer_interval); } /* @@ -383,7 +385,7 @@ static int decay_interval_set(void *data, u64 val) timer_interval = val; - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(timer_interval); return 0; } DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n"); @@ -509,8 +511,8 @@ void __init cec_init(void) if (create_debugfs_nodes()) return; - timer_setup(&cec_timer, cec_timer_fn, 0); - cec_mod_timer(&cec_timer, CEC_TIMER_DEFAULT_INTERVAL); + INIT_DELAYED_WORK(&cec_work, cec_work_fn); + schedule_delayed_work(&cec_work, CEC_TIMER_DEFAULT_INTERVAL); pr_info("Correctable Errors collector initialized.\n"); }
WARNING: multiple messages have this Message-ID (diff)
From: Cong Wang <xiyou.wangcong@gmail.com> To: linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, Cong Wang <xiyou.wangcong@gmail.com>, Tony Luck <tony.luck@intel.com>, Borislav Petkov <bp@alien8.de>, Thomas Gleixner <tglx@linutronix.de> Subject: [PATCH v2 2/2] ras: close the race condition with timer Date: Tue, 16 Apr 2019 14:33:51 -0700 [thread overview] Message-ID: <20190416213351.28999-2-xiyou.wangcong@gmail.com> (raw) Message-ID: <20190416213351.LZcRXRL1pq6_4KGfi9OUKpGRkx4JY9q2DDwikRSIve8@z> (raw) In-Reply-To: <20190416213351.28999-1-xiyou.wangcong@gmail.com> cec_timer_fn() is a timer callback which reads ce_arr.array[] and updates its decay values. Elements could be added to or removed from this global array in parallel, although the array itself will not grow or shrink. del_lru_elem_unlocked() uses FULL_COUNT() as a key to find a right element to remove, which could be affected by the parallel timer. Fix this by converting the timer to a delayed work as suggested by Borislav, to avoid using spinlock. Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector") Cc: Tony Luck <tony.luck@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> --- drivers/ras/cec.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c index a4ff54e50673..5c2040a7389d 100644 --- a/drivers/ras/cec.c +++ b/drivers/ras/cec.c @@ -2,6 +2,7 @@ #include <linux/mm.h> #include <linux/gfp.h> #include <linux/kernel.h> +#include <linux/workqueue.h> #include <asm/mce.h> @@ -131,7 +132,7 @@ static unsigned int count_threshold = COUNT_MASK; #define CEC_TIMER_DEFAULT_INTERVAL 24 * 60 * 60 /* 24 hrs */ #define CEC_TIMER_MIN_INTERVAL 1 * 60 * 60 /* 1h */ #define CEC_TIMER_MAX_INTERVAL 30 * 24 * 60 * 60 /* one month */ -static struct timer_list cec_timer; +static struct delayed_work cec_work; static u64 timer_interval = CEC_TIMER_DEFAULT_INTERVAL; /* @@ -160,20 +161,21 @@ static void do_spring_cleaning(struct ce_array *ca) /* * @interval in seconds */ -static void cec_mod_timer(struct timer_list *t, unsigned long interval) +static void cec_mod_work(unsigned long interval) { unsigned long iv; - iv = interval * HZ + jiffies; - - mod_timer(t, round_jiffies(iv)); + iv = interval * HZ; + mod_delayed_work(system_wq, &cec_work, round_jiffies(iv)); } -static void cec_timer_fn(struct timer_list *unused) +static void cec_work_fn(struct work_struct *work) { + mutex_lock(&ce_mutex); do_spring_cleaning(&ce_arr); + mutex_unlock(&ce_mutex); - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(timer_interval); } /* @@ -383,7 +385,7 @@ static int decay_interval_set(void *data, u64 val) timer_interval = val; - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(timer_interval); return 0; } DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n"); @@ -509,8 +511,8 @@ void __init cec_init(void) if (create_debugfs_nodes()) return; - timer_setup(&cec_timer, cec_timer_fn, 0); - cec_mod_timer(&cec_timer, CEC_TIMER_DEFAULT_INTERVAL); + INIT_DELAYED_WORK(&cec_work, cec_work_fn); + schedule_delayed_work(&cec_work, CEC_TIMER_DEFAULT_INTERVAL); pr_info("Correctable Errors collector initialized.\n"); } -- 2.20.1
next prev reply other threads:[~2019-04-16 21:33 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-16 21:33 [v2,1/2] ras: fix an off-by-one error in __find_elem() Cong Wang 2019-04-16 21:33 ` [PATCH v2 1/2] " Cong Wang 2019-04-16 21:33 ` Cong Wang [this message] 2019-04-16 21:33 ` [PATCH v2 2/2] ras: close the race condition with timer Cong Wang 2019-06-08 15:28 ` [tip:ras/urgent] RAS/CEC: Convert the timer callback to a workqueue tip-bot for Cong Wang 2019-04-16 21:46 ` [v2,1/2] ras: fix an off-by-one error in __find_elem() Borislav Petkov 2019-04-16 21:46 ` [PATCH v2 1/2] " Borislav Petkov 2019-04-16 23:16 ` [v2,1/2] " Cong Wang 2019-04-16 23:16 ` [PATCH v2 1/2] " Cong Wang 2019-04-20 11:34 ` [v2,1/2] " Borislav Petkov 2019-04-20 11:34 ` [PATCH v2 1/2] " Borislav Petkov 2019-04-20 18:25 ` [v2,1/2] " Cong Wang 2019-04-20 18:25 ` [PATCH v2 1/2] " Cong Wang 2019-04-20 19:04 ` [v2,1/2] " Borislav Petkov 2019-04-20 19:04 ` [PATCH v2 1/2] " Borislav Petkov 2019-04-20 19:15 ` [v2,1/2] " Cong Wang 2019-04-20 19:15 ` [PATCH v2 1/2] " Cong Wang 2019-04-21 8:27 ` [v2,1/2] " Borislav Petkov 2019-04-21 8:27 ` [PATCH v2 1/2] " Borislav Petkov
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