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Thu, 29 Jan 2026 19:34:26 -0800 (PST) From: Qing Wang To: zeri@umich.edu Cc: acme@kernel.org, henryzhangjcle@gmail.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, syzbot+2a077cb788749964cf68@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, wangqing7171@gmail.com Subject: Re: [PATCH] perf: Fix data race in perf_event_set_bpf_handler() Date: Fri, 30 Jan 2026 11:34:20 +0800 Message-Id: <20260130033420.23612-1-wangqing7171@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 28 Jan 2026 at 05:29, Henry Zhang wrote: > Thanks, this looks good. I thought my patch is incorrect after review. 1. The RCU protects 'prog->aux' but not 'prog', so 'rcu_dereference(event->prog)' is incorrect. 2. The UAF issue of 'prog' may not exist. It's needed further anlysis. Let's forget my patch. The data race is correctly fixed by your patch but there is still a little suggestion: The 'event->prog = NULL' in perf_event_free_bpf_handler is needed WRITE_ONCE. -- Best regards, Qing