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From: wangxu <wangxu72@huawei.com>
To: <will@kernel.org>, <mark.rutland@arm.com>,
	<linux@armlinux.org.uk>, <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH] ARM/hw_breakpoint: modify dead code for breakpoint_handler()
Date: Wed, 9 Oct 2019 17:27:00 +0800	[thread overview]
Message-ID: <1570613220-59533-1-git-send-email-wangxu72@huawei.com> (raw)

From: Wang Xu <wangxu72@huawei.com>

In perf_event_alloc(), event->overflow_handler is initialized to a
non-null value, which makes enable_single_step(bp, addr) in
breakpoint_handler() never be executed.

As a matter of fact, the branch condition has been updated to
is_default_overflow_handler().

Signed-off-by: Wang Xu <wangxu72@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 b0c195e..586a587 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -822,7 +822,7 @@ 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;
 		}
-- 
1.8.5.6


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             reply	other threads:[~2019-10-09  9:27 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09  9:27 wangxu [this message]
2019-10-11 16:43 ` [PATCH] ARM/hw_breakpoint: modify dead code for breakpoint_handler() Will Deacon
  -- strict thread matches above, loose matches on Subject: below --
2019-10-12  3:28 wangxu

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