From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Sebastian Siewior <bigeasy@linutronix.de>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, "David S. Miller" <davem@davemloft.net>, Fenghua Yu <fenghua.yu@intel.com>, Herbert Xu <herbert@gondor.apana.org.au>, Lai Jiangshan <jiangshanlai@gmail.com>, Len Brown <lenb@kernel.org>, Michael Ellerman <mpe@ellerman.id.au>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Tejun Heo <tj@kernel.org>, Tony Luck <tony.luck@intel.com>, Viresh Kumar <viresh.kumar@linaro.org>, linux-ia64@vger.kernel.org Subject: [patch 03/13] ia64/salinfo: Replace racy task affinity logic Date: Wed, 12 Apr 2017 22:07:29 +0200 [thread overview] Message-ID: <20170412201042.341863457@linutronix.de> (raw) In-Reply-To: 20170412200726.941336635@linutronix.de [-- Attachment #1: ia64-salinfo--Use-work_on_cpu_safe--.patch --] [-- Type: text/plain, Size: 3516 bytes --] Some of the file operations in /proc/sal require to run code on the requested cpu. This is achieved by temporarily setting the affinity of the calling user space thread to the requested CPU and reset it to the original affinity afterwards. That's racy vs. CPU hotplug and concurrent affinity settings for that thread resulting in code executing on the wrong CPU and overwriting the new affinity setting. Replace it by using work_on_cpu_safe() which guarantees to run the code on the requested CPU or to fail in case the CPU is offline. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64@vger.kernel.org --- arch/ia64/kernel/salinfo.c | 31 ++++++++++++------------------- 1 file changed, 12 insertions(+), 19 deletions(-) --- a/arch/ia64/kernel/salinfo.c +++ b/arch/ia64/kernel/salinfo.c @@ -179,14 +179,14 @@ struct salinfo_platform_oemdata_parms { const u8 *efi_guid; u8 **oemdata; u64 *oemdata_size; - int ret; }; -static void +static long salinfo_platform_oemdata_cpu(void *context) { struct salinfo_platform_oemdata_parms *parms = context; - parms->ret = salinfo_platform_oemdata(parms->efi_guid, parms->oemdata, parms->oemdata_size); + + return salinfo_platform_oemdata(parms->efi_guid, parms->oemdata, parms->oemdata_size); } static void @@ -380,16 +380,7 @@ salinfo_log_release(struct inode *inode, return 0; } -static void -call_on_cpu(int cpu, void (*fn)(void *), void *arg) -{ - cpumask_t save_cpus_allowed = current->cpus_allowed; - set_cpus_allowed_ptr(current, cpumask_of(cpu)); - (*fn)(arg); - set_cpus_allowed_ptr(current, &save_cpus_allowed); -} - -static void +static long salinfo_log_read_cpu(void *context) { struct salinfo_data *data = context; @@ -399,6 +390,7 @@ salinfo_log_read_cpu(void *context) /* Clear corrected errors as they are read from SAL */ if (rh->severity == sal_log_severity_corrected) ia64_sal_clear_state_info(data->type); + return 0; } static void @@ -430,7 +422,7 @@ salinfo_log_new_read(int cpu, struct sal spin_unlock_irqrestore(&data_saved_lock, flags); if (!data->saved_num) - call_on_cpu(cpu, salinfo_log_read_cpu, data); + work_on_cpu_safe(cpu, salinfo_log_read_cpu, data); if (!data->log_size) { data->state = STATE_NO_DATA; cpumask_clear_cpu(cpu, &data->cpu_event); @@ -459,11 +451,13 @@ salinfo_log_read(struct file *file, char return simple_read_from_buffer(buffer, count, ppos, buf, bufsize); } -static void +static long salinfo_log_clear_cpu(void *context) { struct salinfo_data *data = context; + ia64_sal_clear_state_info(data->type); + return 0; } static int @@ -486,7 +480,7 @@ salinfo_log_clear(struct salinfo_data *d rh = (sal_log_record_header_t *)(data->log_buffer); /* Corrected errors have already been cleared from SAL */ if (rh->severity != sal_log_severity_corrected) - call_on_cpu(cpu, salinfo_log_clear_cpu, data); + work_on_cpu_safe(cpu, salinfo_log_clear_cpu, data); /* clearing a record may make a new record visible */ salinfo_log_new_read(cpu, data); if (data->state == STATE_LOG_RECORD) { @@ -531,9 +525,8 @@ salinfo_log_write(struct file *file, con .oemdata = &data->oemdata, .oemdata_size = &data->oemdata_size }; - call_on_cpu(cpu, salinfo_platform_oemdata_cpu, &parms); - if (parms.ret) - count = parms.ret; + count = work_on_cpu_safe(cpu, salinfo_platform_oemdata_cpu, + &parms); } else data->oemdata_size = 0; } else
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Sebastian Siewior <bigeasy@linutronix.de>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, "David S. Miller" <davem@davemloft.net>, Fenghua Yu <fenghua.yu@intel.com>, Herbert Xu <herbert@gondor.apana.org.au>, Lai Jiangshan <jiangshanlai@gmail.com>, Len Brown <lenb@kernel.org>, Michael Ellerman <mpe@ellerman.id.au>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Tejun Heo <tj@kernel.org>, Tony Luck <tony.luck@intel.com>, Viresh Kumar <viresh.kumar@linaro.org>, linux-ia64@vger.kernel.org Subject: [patch 03/13] ia64/salinfo: Replace racy task affinity logic Date: Wed, 12 Apr 2017 20:07:29 +0000 [thread overview] Message-ID: <20170412201042.341863457@linutronix.de> (raw) In-Reply-To: 20170412200726.941336635@linutronix.de Some of the file operations in /proc/sal require to run code on the requested cpu. This is achieved by temporarily setting the affinity of the calling user space thread to the requested CPU and reset it to the original affinity afterwards. That's racy vs. CPU hotplug and concurrent affinity settings for that thread resulting in code executing on the wrong CPU and overwriting the new affinity setting. Replace it by using work_on_cpu_safe() which guarantees to run the code on the requested CPU or to fail in case the CPU is offline. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64@vger.kernel.org --- arch/ia64/kernel/salinfo.c | 31 ++++++++++++------------------- 1 file changed, 12 insertions(+), 19 deletions(-) --- a/arch/ia64/kernel/salinfo.c +++ b/arch/ia64/kernel/salinfo.c @@ -179,14 +179,14 @@ struct salinfo_platform_oemdata_parms { const u8 *efi_guid; u8 **oemdata; u64 *oemdata_size; - int ret; }; -static void +static long salinfo_platform_oemdata_cpu(void *context) { struct salinfo_platform_oemdata_parms *parms = context; - parms->ret = salinfo_platform_oemdata(parms->efi_guid, parms->oemdata, parms->oemdata_size); + + return salinfo_platform_oemdata(parms->efi_guid, parms->oemdata, parms->oemdata_size); } static void @@ -380,16 +380,7 @@ salinfo_log_release(struct inode *inode, return 0; } -static void -call_on_cpu(int cpu, void (*fn)(void *), void *arg) -{ - cpumask_t save_cpus_allowed = current->cpus_allowed; - set_cpus_allowed_ptr(current, cpumask_of(cpu)); - (*fn)(arg); - set_cpus_allowed_ptr(current, &save_cpus_allowed); -} - -static void +static long salinfo_log_read_cpu(void *context) { struct salinfo_data *data = context; @@ -399,6 +390,7 @@ salinfo_log_read_cpu(void *context) /* Clear corrected errors as they are read from SAL */ if (rh->severity = sal_log_severity_corrected) ia64_sal_clear_state_info(data->type); + return 0; } static void @@ -430,7 +422,7 @@ salinfo_log_new_read(int cpu, struct sal spin_unlock_irqrestore(&data_saved_lock, flags); if (!data->saved_num) - call_on_cpu(cpu, salinfo_log_read_cpu, data); + work_on_cpu_safe(cpu, salinfo_log_read_cpu, data); if (!data->log_size) { data->state = STATE_NO_DATA; cpumask_clear_cpu(cpu, &data->cpu_event); @@ -459,11 +451,13 @@ salinfo_log_read(struct file *file, char return simple_read_from_buffer(buffer, count, ppos, buf, bufsize); } -static void +static long salinfo_log_clear_cpu(void *context) { struct salinfo_data *data = context; + ia64_sal_clear_state_info(data->type); + return 0; } static int @@ -486,7 +480,7 @@ salinfo_log_clear(struct salinfo_data *d rh = (sal_log_record_header_t *)(data->log_buffer); /* Corrected errors have already been cleared from SAL */ if (rh->severity != sal_log_severity_corrected) - call_on_cpu(cpu, salinfo_log_clear_cpu, data); + work_on_cpu_safe(cpu, salinfo_log_clear_cpu, data); /* clearing a record may make a new record visible */ salinfo_log_new_read(cpu, data); if (data->state = STATE_LOG_RECORD) { @@ -531,9 +525,8 @@ salinfo_log_write(struct file *file, con .oemdata = &data->oemdata, .oemdata_size = &data->oemdata_size }; - call_on_cpu(cpu, salinfo_platform_oemdata_cpu, &parms); - if (parms.ret) - count = parms.ret; + count = work_on_cpu_safe(cpu, salinfo_platform_oemdata_cpu, + &parms); } else data->oemdata_size = 0; } else
next prev parent reply other threads:[~2017-04-12 20:22 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-12 20:07 [patch 00/13] sched/treewide: Clean up various racy task affinity issues Thomas Gleixner 2017-04-12 20:07 ` [patch 01/13] ia64/topology: Remove cpus_allowed manipulation Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-15 14:15 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 02/13] workqueue: Provide work_on_cpu_safe() Thomas Gleixner 2017-04-13 11:11 ` Dou Liyang 2017-04-13 21:28 ` Thomas Gleixner 2017-04-14 4:18 ` Tejun Heo 2017-04-14 8:54 ` Peter Zijlstra 2017-04-14 9:51 ` Thomas Gleixner 2017-04-14 9:56 ` Peter Zijlstra 2017-04-15 14:16 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner [this message] 2017-04-12 20:07 ` [patch 03/13] ia64/salinfo: Replace racy task affinity logic Thomas Gleixner 2017-04-15 14:17 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 04/13] ia64/sn/hwperf: " Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-12 20:53 ` [patch V 2 " Thomas Gleixner 2017-04-12 20:53 ` Thomas Gleixner 2017-04-15 14:17 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 05/13] powerpc/smp: Replace open coded " Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-13 5:47 ` Michael Ellerman 2017-04-15 14:18 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 06/13] sparc/sysfs: Replace racy " Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-13 1:52 ` David Miller 2017-04-13 1:52 ` David Miller 2017-04-13 8:17 ` [patch V2 " Thomas Gleixner 2017-04-13 8:17 ` Thomas Gleixner 2017-04-15 14:18 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 07/13] ACPI/processor: Fix error handling in __acpi_processor_start() Thomas Gleixner 2017-04-15 14:19 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 08/13] ACPI/processor: Replace racy task affinity logic Thomas Gleixner 2017-04-13 11:39 ` Peter Zijlstra 2017-04-13 12:01 ` Thomas Gleixner 2017-04-13 12:52 ` Peter Zijlstra 2017-04-15 14:19 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 09/13] cpufreq/ia64: " Thomas Gleixner 2017-04-12 20:55 ` [patch V2 " Thomas Gleixner 2017-04-15 14:20 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-13 2:42 ` [patch 09/13] " Viresh Kumar 2017-04-12 20:07 ` [patch 10/13] cpufreq/sh: " Thomas Gleixner 2017-04-13 2:46 ` Viresh Kumar 2017-04-15 14:20 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 11/13] cpufreq/sparc-us3: " Thomas Gleixner 2017-04-13 2:48 ` Viresh Kumar 2017-04-15 14:21 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 12/13] cpufreq/sparc-us2e: " Thomas Gleixner 2017-04-13 2:50 ` Viresh Kumar 2017-04-13 8:19 ` [patch V2 " Thomas Gleixner 2017-04-13 8:22 ` [patch V3 " Thomas Gleixner 2017-04-15 14:21 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-13 14:50 ` [patch V2 12/13] " David Miller 2017-04-12 20:07 ` [patch 13/13] crypto: n2 - " Thomas Gleixner 2017-04-13 4:56 ` Herbert Xu 2017-04-13 8:20 ` [patch V2 " Thomas Gleixner 2017-04-13 14:51 ` David Miller 2017-04-15 14:22 ` [tip:sched/core] crypto: N2 " tip-bot for Thomas Gleixner 2017-04-13 9:02 ` [patch 00/13] sched/treewide: Clean up various racy task affinity issues Peter Zijlstra
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