From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794446812; b=FOd6/LoxpH8skjPHdSVO73Qbv5+aTBBpaWX+yzLqXsusylzrJlVI19ATeut/p2XoxUyM ONrsTV7YVIHKhuuVKgZPgSFXo7bpGXBXRxLVeyZrRSEsapAnhf0lcZ+47GB3G4KyVwRh9 1s/QO6WiZ+OOCii/YIk6ZhqqiOw+eiwxM26yIMzcVwGOrR1mFNKdAD4QSS8/U6tEu1vC2 QOkuU1x7rZFZUxn/wjodAuDZsaNnsmAXNAlJSuFIFcx3BvxlqmLDy4c26Mknf+/iZhHIm 0Ihqk0X3gGSh6CQy2yKrN4t0Eccqbx/jLv1DPxH33DhX2DOgFesZZirIkBwRjB8yffw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794446812; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=oDBZSd2HMkUrgeR+h9U1/zObKN23+ppb2T0hvywk+YU=; b=RI6rWBgUpPLmN/CKtP0//6foOrHVihX8MV3IgKeEyC2lUFjc2T6U78fEG9MYmd+wmH2c jY0mCSBlFM6m0V0Kk0iSeJtqMJMtfG/HBBG2r17gvWiDBGnSZxfULlS1iIvJdAL0t/81n GPnQRb0jLGSu95QgsW5xk4m0S1BMUmTLUFnKkzM5klqXAevgDadGFdCjeDN/haDiCvZ/m IcU4P6WZi9TWJntUW2QZCQrc9tkKMbkIAg9ufaVTyxyosrz7EsxsjuRpwrjtcvhUHciEa XJhWlqOX/AG9ilVuw/9l8DwWg8rgtF67nuModEHH9Y9+C/Ojg9ksS4lVpbLbha3uCXQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=itkbYuAo; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72876606A31C; Thu, 12 Nov 2026 01:26:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=itkbYuAo Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C6E41F00A05; Thu, 12 Nov 2026 01:26:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794446812; bh=oDBZSd2HMkUrgeR+h9U1/zObKN23+ppb2T0hvywk+YU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=itkbYuAo2f6eUGLpORZdoFh/Lve+A6mRLYMke8puYIYxfyMJNmwaLceLhBbElvs5F pHKFHfdWnbaiJmPNna9fb5H60+idXlHavbOdpqe7gtgKjRdo0d2lX3oXc9dwebpvTt zY9xn1/eeAXxSpnpRwDE8OTsmV505PkUHzdrQwZz2nggVxRfh4XIhfDylz7NEJURjg q3Ci/vPPS30bcqWc4e3wxjAjl3ktaBNUuvLCPh6EI8yA8c53APXcbofAzdWwaifzGn soVrIN88Aim+YnzABoY6wvlSit8PeshWDU+lV0wQM9xrmZ278D2V/Yod4Se8+g/8uA 8zvc+HxzXgpog== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH v2 01/13] tracing/probes: Check enabled and busy state before unlinking sibling probes Date: Thu, 12 Nov 2026 10:26:48 +0900 Message-ID: <179444680826.345731.12254468152780307145.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <179444679892.345731.5271591537517106679.stgit@devnote2> References: <179444679892.345731.5271591537517106679.stgit@devnote2> User-Agent: StGit/0.19 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit From: Masami Hiramatsu (Google) When a multiprobe event is enabled or referenced (for example, by an eprobe, trigger, or open tracefs file) and a user attempts to delete the event or one of its probes via dynamic_events, checking trace_probe_has_sibling() before the enabled and busy checks allows the first probe to be unlinked and freed while the event is still active, only returning -EBUSY on the last sibling probe. For uprobe events, unlinking and freeing an enabled sibling probe without unregistering its uprobe_consumer also causes a use-after-free. Ensure all four probe types (kprobe, fprobe, uprobe, and eprobe) verify that the event is neither enabled nor busy before unlinking any sibling probe. Fixes: ca89bc071d5e ("tracing/kprobe: Add multi-probe per event support") Fixes: 41af3cf587f4 ("tracing/uprobe: Add multi-probe per uprobe event support") Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Fixes: 334e5519c375 ("tracing/probes: Add fprobe events for tracing function entry and exit.") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_eprobe.c | 12 ++++++++---- kernel/trace/trace_fprobe.c | 8 ++++---- kernel/trace/trace_kprobe.c | 8 ++++---- kernel/trace/trace_uprobe.c | 8 ++++++-- 4 files changed, 22 insertions(+), 14 deletions(-) diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 474be2f5ccd9..f1590c9af6b2 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -94,14 +94,18 @@ static int eprobe_dyn_event_show(struct seq_file *m, struct dyn_event *ev) static int unregister_trace_eprobe(struct trace_eprobe *ep) { - /* If other probes are on the event, just unregister eprobe */ - if (trace_probe_has_sibling(&ep->tp)) - goto unreg; - /* Enabled event can not be unregistered */ if (trace_probe_is_enabled(&ep->tp)) return -EBUSY; + /* If there's a reference to the dynamic event */ + if (trace_event_dyn_busy(trace_probe_event_call(&ep->tp))) + return -EBUSY; + + /* If other probes are on the event, just unregister eprobe */ + if (trace_probe_has_sibling(&ep->tp)) + goto unreg; + /* Will fail if probe is being used by ftrace or perf */ if (trace_probe_unregister_event_call(&ep->tp)) return -EBUSY; diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index 4e9034ebc3fb..77f2228d44ba 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -853,10 +853,6 @@ static void __unregister_trace_fprobe(struct trace_fprobe *tf) /* Unregister a trace_probe and probe_event */ static int unregister_trace_fprobe(struct trace_fprobe *tf) { - /* If other probes are on the event, just unregister fprobe */ - if (trace_probe_has_sibling(&tf->tp)) - goto unreg; - /* Enabled event can not be unregistered */ if (trace_probe_is_enabled(&tf->tp)) return -EBUSY; @@ -865,6 +861,10 @@ static int unregister_trace_fprobe(struct trace_fprobe *tf) if (trace_event_dyn_busy(trace_probe_event_call(&tf->tp))) return -EBUSY; + /* If other probes are on the event, just unregister fprobe */ + if (trace_probe_has_sibling(&tf->tp)) + goto unreg; + /* Will fail if probe is being used by ftrace or perf */ if (unregister_fprobe_event(tf)) return -EBUSY; diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index e41a7c113646..a42af0e66009 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -548,10 +548,6 @@ static void __unregister_trace_kprobe(struct trace_kprobe *tk) /* Unregister a trace_probe and probe_event */ static int unregister_trace_kprobe(struct trace_kprobe *tk) { - /* If other probes are on the event, just unregister kprobe */ - if (trace_probe_has_sibling(&tk->tp)) - goto unreg; - /* Enabled event can not be unregistered */ if (trace_probe_is_enabled(&tk->tp)) return -EBUSY; @@ -560,6 +556,10 @@ static int unregister_trace_kprobe(struct trace_kprobe *tk) if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp))) return -EBUSY; + /* If other probes are on the event, just unregister kprobe */ + if (trace_probe_has_sibling(&tk->tp)) + goto unreg; + /* Will fail if probe is being used by ftrace or perf */ if (unregister_kprobe_event(tk)) return -EBUSY; diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 22cc3c8181b8..146da04b93a8 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -396,13 +396,17 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu) { int ret; - if (trace_probe_has_sibling(&tu->tp)) - goto unreg; + /* Enabled event can not be unregistered */ + if (trace_probe_is_enabled(&tu->tp)) + return -EBUSY; /* If there's a reference to the dynamic event */ if (trace_event_dyn_busy(trace_probe_event_call(&tu->tp))) return -EBUSY; + if (trace_probe_has_sibling(&tu->tp)) + goto unreg; + ret = unregister_uprobe_event(tu); if (ret) return ret;