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

[Will Deacon]

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/

Will