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Thu, 04 Sep 2025 00:07:40 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFAG1gjB38L4a5W8ATy0+T7HjTHZIKgrGns44FrZQ91ODwrAyl3bQdk5UUgaAnn5EYjP5/6vQ== X-Received: by 2002:adf:a406:0:b0:3e1:7964:2c17 with SMTP id ffacd0b85a97d-3e17964361cmr348607f8f.62.1756969660313; Thu, 04 Sep 2025 00:07:40 -0700 (PDT) Received: from gmonaco-thinkpadt14gen3.rmtit.csb ([185.107.56.42]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3df4fd372c1sm4413056f8f.29.2025.09.04.00.07.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Sep 2025 00:07:39 -0700 (PDT) Message-ID: <8fa89db22320220e1bc411ded115f0a40097f961.camel@redhat.com> Subject: Re: [PATCH] rv: Fix missing mutex unlock in rv_register_monitor() From: Gabriele Monaco To: Zhen Ni , Nam Cao Cc: linux-trace-kernel@vger.kernel.org, Steven Rostedt , mhiramat@kernel.org, Mathieu Desnoyers Date: Thu, 04 Sep 2025 09:07:38 +0200 In-Reply-To: <20250903065112.1878330-1-zhen.ni@easystack.cn> References: <20250903065112.1878330-1-zhen.ni@easystack.cn> Autocrypt: addr=gmonaco@redhat.com; prefer-encrypt=mutual; keydata=mDMEZuK5YxYJKwYBBAHaRw8BAQdAmJ3dM9Sz6/Hodu33Qrf8QH2bNeNbOikqYtxWFLVm0 1a0JEdhYnJpZWxlIE1vbmFjbyA8Z21vbmFjb0ByZWRoYXQuY29tPoiZBBMWCgBBFiEEysoR+AuB3R Zwp6j270psSVh4TfIFAmbiuWMCGwMFCQWjmoAFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgk Q70psSVh4TfJzZgD/TXjnqCyqaZH/Y2w+YVbvm93WX2eqBqiVZ6VEjTuGNs8A/iPrKbzdWC7AicnK xyhmqeUWOzFx5P43S1E1dhsrLWgP User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: GhW5h5O_fkxsXMGqZQxh3z6nD9JzNnmQ_oD8wcUD8p8_1756969661 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2025-09-03 at 14:51 +0800, Zhen Ni wrote: > If create_monitor_dir() fails, the function returns directly without > releasing rv_interface_lock. This leaves the mutex locked and causes > subsequent monitor registration attempts to deadlock. >=20 > Fix it by making the error path jump to out_unlock, ensuring that the > mutex is always released before returning. >=20 > Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct > rv_monitor") > Signed-off-by: Zhen Ni Good catch, thank you! Reviewed-by: Gabriele Monaco I would also add a: Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monito= r") (Adding Nam to the loop, as author of that patch) Thanks, Gabriele > --- > =C2=A0kernel/trace/rv/rv.c | 2 +- > =C2=A01 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c > index 1482e91c39f4..e35565dd2dc5 100644 > --- a/kernel/trace/rv/rv.c > +++ b/kernel/trace/rv/rv.c > @@ -805,7 +805,7 @@ int rv_register_monitor(struct rv_monitor > *monitor, struct rv_monitor *parent) > =C2=A0 > =C2=A0=09retval =3D create_monitor_dir(monitor, parent); > =C2=A0=09if (retval) > -=09=09return retval; > +=09=09goto out_unlock; > =C2=A0 > =C2=A0=09/* keep children close to the parent for easier > visualisation */ > =C2=A0=09if (parent)