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([2a01:4b00:bf28:2e00:ff96:2dac:a39:3e10]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a073cb2acbsm741577f8f.40.2025.04.24.17.31.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Apr 2025 17:31:19 -0700 (PDT) Message-ID: <55eb79ff-4020-40ba-b690-756ab746ade7@gmail.com> Date: Fri, 25 Apr 2025 01:31:17 +0100 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next] Use thread-safe function pointer in libbpf_print To: ">" , bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Mykyta Yatsenko , Yonghong Song , Jordan Rome , Jiri Olsa , Kernel Team References: <20250424221457.793068-1-jonathan.wiepert@gmail.com> Content-Language: en-US From: Mykyta Yatsenko In-Reply-To: <20250424221457.793068-1-jonathan.wiepert@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/24/25 23:14, > wrote: > From: Jonathan Wiepert > > This patch fixes a thread safety bug where libbpf_print uses the > global variable storing the print function pointer rather than the local > variable that had the print function set via __atomic_load_n. > > Signed-off-by: Jonathan Wiepert > --- > tools/lib/bpf/libbpf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 56250b5ac5b0..ea97a84460cd 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -284,7 +284,7 @@ void libbpf_print(enum libbpf_print_level level, const char *format, ...) > old_errno = errno; > > va_start(args, format); > - __libbpf_pr(level, format, args); > + print_fn(level, format, args); > va_end(args); > > errno = old_errno; Acked-by: Mykyta Yatsenko