* [PATCH RT 02/10] ARM: smp: Move clear_tasks_mm_cpumask() call to __cpu_die() [not found] <20160226213911.445523575@goodmis.org> @ 2016-02-26 21:39 ` Steven Rostedt 0 siblings, 0 replies; 2+ messages in thread From: Steven Rostedt @ 2016-02-26 21:39 UTC (permalink / raw) To: linux-arm-kernel 3.12.54-rt73-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Grygorii Strashko <grygorii.strashko@ti.com> When running with the RT-kernel (4.1.5-rt5) on TI OMAP dra7-evm and trying to do Suspend to RAM, the following backtrace occurs: Disabling non-boot CPUs ... PM: noirq suspend of devices complete after 7.295 msecs Disabling non-boot CPUs ... BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 1, irqs_disabled(): 128, pid: 18, name: migration/1 INFO: lockdep is turned off. irq event stamp: 122 hardirqs last enabled at (121): [<c06ac0ac>] _raw_spin_unlock_irqrestore+0x88/0x90 hardirqs last disabled at (122): [<c06abed0>] _raw_spin_lock_irq+0x28/0x5c softirqs last enabled at (0): [<c003d294>] copy_process.part.52+0x410/0x19d8 softirqs last disabled at (0): [< (null)>] (null) Preemption disabled at:[< (null)>] (null) CPU: 1 PID: 18 Comm: migration/1 Tainted: G W 4.1.4-rt3-01046-g96ac8da #204 Hardware name: Generic DRA74X (Flattened Device Tree) [<c0019134>] (unwind_backtrace) from [<c0014774>] (show_stack+0x20/0x24) [<c0014774>] (show_stack) from [<c06a70f4>] (dump_stack+0x88/0xdc) [<c06a70f4>] (dump_stack) from [<c006cab8>] (___might_sleep+0x198/0x2a8) [<c006cab8>] (___might_sleep) from [<c06ac4dc>] (rt_spin_lock+0x30/0x70) [<c06ac4dc>] (rt_spin_lock) from [<c013f790>] (find_lock_task_mm+0x9c/0x174) [<c013f790>] (find_lock_task_mm) from [<c00409ac>] (clear_tasks_mm_cpumask+0xb4/0x1ac) [<c00409ac>] (clear_tasks_mm_cpumask) from [<c00166a4>] (__cpu_disable+0x98/0xbc) [<c00166a4>] (__cpu_disable) from [<c06a2e8c>] (take_cpu_down+0x1c/0x50) [<c06a2e8c>] (take_cpu_down) from [<c00f2600>] (multi_cpu_stop+0x11c/0x158) [<c00f2600>] (multi_cpu_stop) from [<c00f2a9c>] (cpu_stopper_thread+0xc4/0x184) [<c00f2a9c>] (cpu_stopper_thread) from [<c0069058>] (smpboot_thread_fn+0x18c/0x324) [<c0069058>] (smpboot_thread_fn) from [<c00649c4>] (kthread+0xe8/0x104) [<c00649c4>] (kthread) from [<c0010058>] (ret_from_fork+0x14/0x3c) CPU1: shutdown PM: Calling sched_clock_suspend+0x0/0x40 PM: Calling timekeeping_suspend+0x0/0x2e0 PM: Calling irq_gc_suspend+0x0/0x68 PM: Calling fw_suspend+0x0/0x2c PM: Calling cpu_pm_suspend+0x0/0x28 Also, sometimes system stucks right after displaying "Disabling non-boot CPUs ...". The root cause of above backtrace is task_lock() which takes a sleeping lock on -RT. To fix the issue, move clear_tasks_mm_cpumask() call from __cpu_disable() to __cpu_die() which is called on the thread which is asking for a target CPU to be shutdown. In addition, this change restores CPUhotplug functionality on TI OMAP dra7-evm and CPU1 can be unplugged/plugged many times. Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <linux-arm-kernel@lists.infradead.org> Cc: Sekhar Nori <nsekhar@ti.com> Cc: Austin Schuh <austin@peloton-tech.com> Cc: <philipp@peloton-tech.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: <bigeasy@linutronix.de> Cc: stable-rt at vger.kernel.org Link: http://lkml.kernel.org/r/1441995683-30817-1-git-send-email-grygorii.strashko at ti.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- arch/arm/kernel/smp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index bd1b9e633356..2f7325963bf5 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -207,8 +207,6 @@ int __cpu_disable(void) flush_cache_louis(); local_flush_tlb_all(); - clear_tasks_mm_cpumask(cpu); - return 0; } @@ -224,6 +222,9 @@ void __cpu_die(unsigned int cpu) pr_err("CPU%u: cpu didn't die\n", cpu); return; } + + clear_tasks_mm_cpumask(cpu); + printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); /* -- 2.7.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
[parent not found: <20160226213551.557375746@goodmis.org>]
* [PATCH RT 02/10] ARM: smp: Move clear_tasks_mm_cpumask() call to __cpu_die() [not found] <20160226213551.557375746@goodmis.org> @ 2016-02-26 21:35 ` Steven Rostedt 0 siblings, 0 replies; 2+ messages in thread From: Steven Rostedt @ 2016-02-26 21:35 UTC (permalink / raw) To: linux-arm-kernel 3.14.61-rt63-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Grygorii Strashko <grygorii.strashko@ti.com> When running with the RT-kernel (4.1.5-rt5) on TI OMAP dra7-evm and trying to do Suspend to RAM, the following backtrace occurs: Disabling non-boot CPUs ... PM: noirq suspend of devices complete after 7.295 msecs Disabling non-boot CPUs ... BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 1, irqs_disabled(): 128, pid: 18, name: migration/1 INFO: lockdep is turned off. irq event stamp: 122 hardirqs last enabled at (121): [<c06ac0ac>] _raw_spin_unlock_irqrestore+0x88/0x90 hardirqs last disabled at (122): [<c06abed0>] _raw_spin_lock_irq+0x28/0x5c softirqs last enabled at (0): [<c003d294>] copy_process.part.52+0x410/0x19d8 softirqs last disabled at (0): [< (null)>] (null) Preemption disabled at:[< (null)>] (null) CPU: 1 PID: 18 Comm: migration/1 Tainted: G W 4.1.4-rt3-01046-g96ac8da #204 Hardware name: Generic DRA74X (Flattened Device Tree) [<c0019134>] (unwind_backtrace) from [<c0014774>] (show_stack+0x20/0x24) [<c0014774>] (show_stack) from [<c06a70f4>] (dump_stack+0x88/0xdc) [<c06a70f4>] (dump_stack) from [<c006cab8>] (___might_sleep+0x198/0x2a8) [<c006cab8>] (___might_sleep) from [<c06ac4dc>] (rt_spin_lock+0x30/0x70) [<c06ac4dc>] (rt_spin_lock) from [<c013f790>] (find_lock_task_mm+0x9c/0x174) [<c013f790>] (find_lock_task_mm) from [<c00409ac>] (clear_tasks_mm_cpumask+0xb4/0x1ac) [<c00409ac>] (clear_tasks_mm_cpumask) from [<c00166a4>] (__cpu_disable+0x98/0xbc) [<c00166a4>] (__cpu_disable) from [<c06a2e8c>] (take_cpu_down+0x1c/0x50) [<c06a2e8c>] (take_cpu_down) from [<c00f2600>] (multi_cpu_stop+0x11c/0x158) [<c00f2600>] (multi_cpu_stop) from [<c00f2a9c>] (cpu_stopper_thread+0xc4/0x184) [<c00f2a9c>] (cpu_stopper_thread) from [<c0069058>] (smpboot_thread_fn+0x18c/0x324) [<c0069058>] (smpboot_thread_fn) from [<c00649c4>] (kthread+0xe8/0x104) [<c00649c4>] (kthread) from [<c0010058>] (ret_from_fork+0x14/0x3c) CPU1: shutdown PM: Calling sched_clock_suspend+0x0/0x40 PM: Calling timekeeping_suspend+0x0/0x2e0 PM: Calling irq_gc_suspend+0x0/0x68 PM: Calling fw_suspend+0x0/0x2c PM: Calling cpu_pm_suspend+0x0/0x28 Also, sometimes system stucks right after displaying "Disabling non-boot CPUs ...". The root cause of above backtrace is task_lock() which takes a sleeping lock on -RT. To fix the issue, move clear_tasks_mm_cpumask() call from __cpu_disable() to __cpu_die() which is called on the thread which is asking for a target CPU to be shutdown. In addition, this change restores CPUhotplug functionality on TI OMAP dra7-evm and CPU1 can be unplugged/plugged many times. Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <linux-arm-kernel@lists.infradead.org> Cc: Sekhar Nori <nsekhar@ti.com> Cc: Austin Schuh <austin@peloton-tech.com> Cc: <philipp@peloton-tech.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: <bigeasy@linutronix.de> Cc: stable-rt at vger.kernel.org Link: http://lkml.kernel.org/r/1441995683-30817-1-git-send-email-grygorii.strashko at ti.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- arch/arm/kernel/smp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 8cd3724714fe..0480b2685da0 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -209,8 +209,6 @@ int __cpu_disable(void) flush_cache_louis(); local_flush_tlb_all(); - clear_tasks_mm_cpumask(cpu); - return 0; } @@ -226,6 +224,9 @@ void __cpu_die(unsigned int cpu) pr_err("CPU%u: cpu didn't die\n", cpu); return; } + + clear_tasks_mm_cpumask(cpu); + printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); /* -- 2.7.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
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2016-02-26 21:39 ` [PATCH RT 02/10] ARM: smp: Move clear_tasks_mm_cpumask() call to __cpu_die() Steven Rostedt
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2016-02-26 21:35 ` Steven Rostedt
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