| From: Yang Shi <yang.shi@linaro.org> |
| Date: Thu, 10 Nov 2016 16:17:55 -0800 |
| Subject: [PATCH] arm: kprobe: replace patch_lock to raw lock |
| |
| When running kprobe on -rt kernel, the below bug is caught: |
| |
| BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931 |
| in_atomic(): 1, irqs_disabled(): 128, pid: 14, name: migration/0 |
| INFO: lockdep is turned off. |
| irq event stamp: 238 |
| hardirqs last enabled at (237): [<80b5aecc>] _raw_spin_unlock_irqrestore+0x88/0x90 |
| hardirqs last disabled at (238): [<80b56d88>] __schedule+0xec/0x94c |
| softirqs last enabled at (0): [<80225584>] copy_process.part.5+0x30c/0x1994 |
| softirqs last disabled at (0): [< (null)>] (null) |
| Preemption disabled at:[<802f2b98>] cpu_stopper_thread+0xc0/0x140 |
| |
| CPU: 0 PID: 14 Comm: migration/0 Tainted: G O 4.8.3-rt2 #1 |
| Hardware name: Freescale LS1021A |
| [<80212e7c>] (unwind_backtrace) from [<8020cd2c>] (show_stack+0x20/0x24) |
| [<8020cd2c>] (show_stack) from [<80689e14>] (dump_stack+0xa0/0xcc) |
| [<80689e14>] (dump_stack) from [<8025a43c>] (___might_sleep+0x1b8/0x2a4) |
| [<8025a43c>] (___might_sleep) from [<80b5b324>] (rt_spin_lock+0x34/0x74) |
| [<80b5b324>] (rt_spin_lock) from [<80b5c31c>] (__patch_text_real+0x70/0xe8) |
| [<80b5c31c>] (__patch_text_real) from [<80b5c3ac>] (patch_text_stop_machine+0x18/0x20) |
| [<80b5c3ac>] (patch_text_stop_machine) from [<802f2920>] (multi_cpu_stop+0xfc/0x134) |
| [<802f2920>] (multi_cpu_stop) from [<802f2ba0>] (cpu_stopper_thread+0xc8/0x140) |
| [<802f2ba0>] (cpu_stopper_thread) from [<802563a4>] (smpboot_thread_fn+0x1a4/0x354) |
| [<802563a4>] (smpboot_thread_fn) from [<80251d38>] (kthread+0x104/0x11c) |
| [<80251d38>] (kthread) from [<80207f70>] (ret_from_fork+0x14/0x24) |
| |
| Since patch_text_stop_machine() is called in stop_machine() which disables IRQ, |
| sleepable lock should be not used in this atomic context, so replace patch_lock |
| to raw lock. |
| |
| Signed-off-by: Yang Shi <yang.shi@linaro.org> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| arch/arm/kernel/patch.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/arch/arm/kernel/patch.c |
| +++ b/arch/arm/kernel/patch.c |
| @@ -15,7 +15,7 @@ struct patch { |
| unsigned int insn; |
| }; |
| |
| -static DEFINE_SPINLOCK(patch_lock); |
| +static DEFINE_RAW_SPINLOCK(patch_lock); |
| |
| static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags) |
| __acquires(&patch_lock) |
| @@ -32,7 +32,7 @@ static void __kprobes *patch_map(void *a |
| return addr; |
| |
| if (flags) |
| - spin_lock_irqsave(&patch_lock, *flags); |
| + raw_spin_lock_irqsave(&patch_lock, *flags); |
| else |
| __acquire(&patch_lock); |
| |
| @@ -47,7 +47,7 @@ static void __kprobes patch_unmap(int fi |
| clear_fixmap(fixmap); |
| |
| if (flags) |
| - spin_unlock_irqrestore(&patch_lock, *flags); |
| + raw_spin_unlock_irqrestore(&patch_lock, *flags); |
| else |
| __release(&patch_lock); |
| } |