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From:   Will Deacon <will@kernel.org>
To:     linux-kernel@vger.kernel.org
Cc:     kernel-team@android.com, akpm@linux-foundation.org,
        Will Deacon <will@kernel.org>,
        "K . Prasad" <prasad@linux.vnet.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Frederic Weisbecker <frederic@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Quentin Perret <qperret@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH 1/3] samples/hw_breakpoint: Drop HW_BREAKPOINT_R when reporting writes
Date:   Fri, 21 Feb 2020 11:44:02 +0000
Message-Id: <20200221114404.14641-2-will@kernel.org>
In-Reply-To: <20200221114404.14641-1-will@kernel.org>
References: <20200221114404.14641-1-will@kernel.org>
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Given the name of a kernel symbol, the 'data_breakpoint' test claims to
"report any write operations on the kernel symbol". However, it creates
the breakpoint using both HW_BREAKPOINT_W and HW_BREAKPOINT_R, which
menas it also fires for read access.

Drop HW_BREAKPOINT_R from the breakpoint attributes.

Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 samples/hw_breakpoint/data_breakpoint.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c
index c58504774118..469b36f93696 100644
--- a/samples/hw_breakpoint/data_breakpoint.c
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -45,7 +45,7 @@ static int __init hw_break_module_init(void)
 	hw_breakpoint_init(&attr);
 	attr.bp_addr = kallsyms_lookup_name(ksym_name);
 	attr.bp_len = HW_BREAKPOINT_LEN_4;
-	attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
+	attr.bp_type = HW_BREAKPOINT_W;
 
 	sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler, NULL);
 	if (IS_ERR((void __force *)sample_hbp)) {
-- 
2.25.0.265.gbab2e86ba0-goog