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| author | Grygorii Strashko <grygorii.strashko@ti.com> | 2018-05-08 16:19:40 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-19 12:53:46 +0200 |
| commit | 98f1b5a762f7bee20785ed576630386ddcc62483 (patch) | |
| tree | 4364a8bc573bb8313833a6faae9f54d717158aa1 /arch/arm/kernel | |
| parent | ARM: 8764/1: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size (diff) | |
| download | linux-98f1b5a762f7bee20785ed576630386ddcc62483.tar.xz linux-98f1b5a762f7bee20785ed576630386ddcc62483.zip | |
ARM: 8765/1: smp: Move clear_tasks_mm_cpumask() call to __cpu_die()
Suspending a CPU on a RT kernel results in the following backtrace:
| 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
| 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
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 CPU hotplug
functionality on ARM CPU1 can be unplugged/plugged many times.
Link: http://lkml.kernel.org/r/1441995683-30817-1-git-send-email-grygorii.strashko@ti.com
[bigeasy: slighty edited the commit message]
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
| -rw-r--r-- | arch/arm/kernel/smp.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 2da087926ebe..b9e08f50df41 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -236,8 +236,6 @@ int __cpu_disable(void) flush_cache_louis(); local_flush_tlb_all(); - clear_tasks_mm_cpumask(cpu); - return 0; } @@ -255,6 +253,7 @@ void __cpu_die(unsigned int cpu) } pr_debug("CPU%u: shutdown\n", cpu); + clear_tasks_mm_cpumask(cpu); /* * platform_cpu_kill() is generally expected to do the powering off * and/or cutting of clocks to the dying CPU. Optionally, this may |