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=1794558493; b=Tu452xmqQPdtyquJtlf58PCwypIMk+ACIDqDGrLdpB0P0NFR4pdA6Ku5ePIlTwlMLoyO kYO1FSXFfbzckaFkEFDZl/3FPty4dI1VfSgdu0W/i59GXmPfNrDic+CCO8vqPtIyQkTX9 9/2kkkwMw3pxY52V01guzzxNKzT5LbxKz1WvUtY/yNntpXzxoTKTGpHKn0vlhjJoKXvyH XGhUTSE/IRjCS1WumP4FiE2LIq84AxeRHuSTrR7FvJtAtzMAXGhrunAFBgtdsnEDUp5ET hNuPsupe1eMatO7jjWUuHXws7AYW6+g15J4+RMsCmNjCujzXjwdnahXxgmmQoUSNiVA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794558493; 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=5cwMlYNXQaS6Q1MBZXtVn+BdOyBtI/jpMMO3ES8YdZcxqQ4JfMi3qftoAcCGEDsAAoQu 03KXMbOogpFoUHyCHDlP02QyevYTiFfOdvbQnjYGH6FCiwmlFXtPYIuwsQMiCPRNfu2Q4 6FBgEchBmW20G5ukcoa/oogoLzHStF2gx4uvSPSZTu7cLqb6Uege5JAi3VOYtnAcM90wC XPq4kOE69Fq7/b+jrLZ6rrmC1GOU1PHm9UmqDediiXZ3GatxcErvvdxfxv7FopGy6Bjuy f+R9VrxftgNV1RuliqPd6n4lk5flgX/1aM8V3yXF97EJRum34t4hBl6VOXBBuKWOtlg== 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=QoY2fIA5; 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 1EC62606B62F; Fri, 13 Nov 2026 08:28:12 +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=QoY2fIA5 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48E981F000C4; Fri, 13 Nov 2026 08:28:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794558492; bh=oDBZSd2HMkUrgeR+h9U1/zObKN23+ppb2T0hvywk+YU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QoY2fIA5LQt4NQjMyCRwCOBzLKy9SbK7iofgQsQmJ5zUHGTHe1XDwH2VtIUwGWvKt AHgJu/5VfLv49dgkLicqvBeI+749Rnf2IxPGCbE9IB056+IRBl2rGqkcNnmCLToMF6 O1SziYWCH2bLM+CQbcJQJoxKkDW5yO5qZ7bdXOetpfKk8awTbDf1sha6VjulEfbB7q VOzOvnwwulr6ryNB9ewQBRQtJJC/WRWDBGNaVb1RWd9QDLZFaJw22V8WSnDaKx1Lpo TBkHJ0+m/0cFAcbPjzA0pcelz0UWYD/8IJSrKYVjbyvshkR8kBFRRMcGD4moZRc4av W38lAqnub/Scg== 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 v3 01/13] tracing/probes: Check enabled and busy state before unlinking sibling probes Date: Fri, 13 Nov 2026 17:28:09 +0900 Message-ID: <179455848898.403392.17675270675769076596.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <179455847934.403392.15146485751358774349.stgit@devnote2> References: <179455847934.403392.15146485751358774349.stgit@devnote2> User-Agent: StGit/0.19 X-Mailing-List: linux-trace-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;