From: Zhen Lei <thunder.leizhen@huawei.com>
Date: Thu, 18 Feb 2021 03:00:05 +0100
Subject: ARM: 9064/1: hw_breakpoint: Do not directly check the event's
overflow_handler hook
Git-commit: a506bd5756290821a4314f502b4bafc2afcf5260
Patch-mainline: v5.13-rc1
References: bsc#1220751 CVE-2021-47006
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.
Comments from Zhen Lei:
https://patchwork.kernel.org/project/linux-arm-kernel/patch/20210207105934.2001-1-thunder.leizhen@huawei.com/
Fixes: 1879445dfa7b ("perf/core: Set event's default ::overflow_handler()")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Wang Nan <wangnan0@huawei.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Matthias Brugger <mbrugger@suse.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 08660ae9dcbc..b1423fb130ea 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;
}
--
2.43.2