From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 36DF4483BFF for ; Thu, 27 Aug 2026 15:09:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787843366; cv=none; b=L63VxuRmVt39gh4ew7M15Po+gJbzbbFT1NOZp2Zc+cUl1d/JKaxWyDaXliWGgdr+bZp2Ux1dxI+ztViXrDKWVMEdi3uJ6HzCn6hPozKqTnmjTDVe8xqNsaggCJk7w7HtXIc8Jtm4xYDkWRif8XDy9eFrbjZQkcH1NeeBWtH5biM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787843366; c=relaxed/simple; bh=/F6DF9N6aI26k2SDHGgLnmmPKxBwn4ZVAH11GI8tveE=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=dUyWCyRYjRYtq6m6lydqIjPAQyKOieNta3lE+2AQu5k8fAZjuzoP+a3A2ewtKHmOH1KA5a8DmqdTCdVJRryDy82v+Iz6LdJ6UbiCi+KZsqR2UKNaLLJq31CCvBKLHeTWH6FxDExAOSCWiWIlgcAzAPuX5CULr0nosawy84bpDSE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aVwm26yt; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aVwm26yt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF1201F00ACF; Thu, 27 Aug 2026 15:09:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787843363; bh=b9FCRmxqVb1GJL/GzWj6/s/4yvGvvUOtw/dfPPgDqJ0=; h=Date:From:To:Cc:Subject:References; b=aVwm26ytG5vCtBjhbP4WGCbepn+mVciOnp2gejjpx6ib2uCPVtzharPqBH9i9pEFm BYMKUanTVW6sq7JptmoDDatIiEtfUlrNzd+SliMzLv0HYawdYrgwTNXt1k9rfFE6Dm K3iGT4SMJfnv7plQZdCFugOKWw5oXgWOEtw/VnMz7vAuGvdkYYXsGl2khUIfLP4q1W 2yUuadg0FZnHsSjd0ZeE6czeus0mcNQusV0+fSJGqlRPQ++r8pN5+0Qql942U/9iTB agVa5yPJqIkKs/gZH5gW4umb8Gv0bhoDbSnlaq8SiJr3tMKaaMgaVRNr62CS1+qCv0 tZgbyRCp20oIQ== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1wzbk3-00000008PHU-3RVF; Thu, 27 Aug 2026 11:10:11 -0400 Message-ID: <20260827151011.689123441@kernel.org> User-Agent: quilt/0.69 Date: Thu, 27 Aug 2026 11:09:56 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Deepanshu Kartikey , Haotian Zhang , Hui Su , Vincent Donnefort Subject: [for-linus][PATCH 7/7] samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify References: <20260827150949.304280511@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Haotian Zhang ftrace_direct_multi_init() assigns kthread_run()'s return value to simple_tsk without an IS_ERR() check. When kthread_run() fails it returns ERR_PTR(-ENOMEM), but init still returns 0, so the module loads with simple_tsk holding an error pointer. On unload, ftrace_direct_multi_exit() then passes that ERR_PTR to kthread_stop(), leading to a null-pointer-dereference. Check the return value of kthread_run() with IS_ERR(); on failure, unregister the ftrace direct call and propagate the error code. Link: https://patch.msgid.link/20260826015050.10772-1-vulab@iscas.ac.cn Fixes: e1067a07cfbc ("ftrace/samples: Add module to test multi direct modify interface") Suggested-by: Steven Rostedt Signed-off-by: Haotian Zhang Signed-off-by: Steven Rostedt --- samples/ftrace/ftrace-direct-multi-modify.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c index 7a7822dfeb50..b03766c6217b 100644 --- a/samples/ftrace/ftrace-direct-multi-modify.c +++ b/samples/ftrace/ftrace-direct-multi-modify.c @@ -364,9 +364,15 @@ static int __init ftrace_direct_multi_init(void) ret = register_ftrace_direct(&direct, my_tramp); - if (!ret) - simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); - return ret; + if (ret) + return ret; + simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); + if (IS_ERR(simple_tsk)) { + unregister_ftrace_direct(&direct, my_tramp, true); + return PTR_ERR(simple_tsk); + } + + return 0; } static void __exit ftrace_direct_multi_exit(void) -- 2.53.0