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

[Leizhen (ThunderTown)]

On 2021/2/18 17:13, Will Deacon wrote:
> On Thu, Feb 18, 2021 at 10:03:22AM +0800, Leizhen (ThunderTown) wrote:
>>
>>
>> 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
> 
> Thanks, although you forgot to add my Ack!

Sorry, the first time I operated this web, the patch in the attachment
can no longer be updated. I just mentioned it in the new "Node".

> 
> Will
> 
> .
>