[PATCH 1/1] ARM: hw_breakpoint: Do not directly check the event's overflow_handler hook

[Leizhen (ThunderTown)]

On 2021/2/12 18:02, Will Deacon wrote:
> On Sun, Feb 07, 2021 at 06:59:34PM +0800, Zhen Lei wrote:
>> The commit 1879445dfa7b ("perf/core: Set event's default
>> ::overflow_handler()") set a default event->overflow_handler in
>> perf_event_alloc(), and replace the check event->overflow_handler with
>> is_default_overflow_handler(), but one is missing.
>>
>> Currently, the bp->overflow_handler can not be NULL. As a result,
>> enable_single_step() is always not invoked.
>>
>> Fixes: 1879445dfa7b ("perf/core: Set event's default ::overflow_handler()")
>> Signed-off-by: Zhen Lei <thunder.leizhen at huawei.com>
>> Cc: Wang Nan <wangnan0 at huawei.com>
>> ---
>>  arch/arm/kernel/hw_breakpoint.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
>> index 08660ae9dcbce1c..b1423fb130ea4a0 100644
>> --- a/arch/arm/kernel/hw_breakpoint.c
>> +++ b/arch/arm/kernel/hw_breakpoint.c
>> @@ -886,7 +886,7 @@ static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
>>  			info->trigger = addr;
>>  			pr_debug("breakpoint fired: address = 0x%x\n", addr);
>>  			perf_bp_event(bp, regs);
>> -			if (!bp->overflow_handler)
>> +			if (is_default_overflow_handler(bp))
>>  				enable_single_step(bp, addr);
>>  			goto unlock;
>>  		}
> 
> Acked-by: Will Deacon <will at kernel.org>
> 
> Please can you put this into the patch tracker?
> 
> https://www.arm.linux.org.uk/developer/patches/

I've added it.

https://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=9064/1

> 
> Will
> 
> .
>