From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cstnet.cn (smtp81.cstnet.cn [159.226.251.81]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 90F893D9DB1; Tue, 25 Aug 2026 09:34:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.81 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787650489; cv=none; b=Wqzw6vf97q0miGyeiSKBD8qQ8U0GmMjZX0CTfmdCzRMlHBEbV89y+MkkAXeHUi8ubusF6Yy23cVcPebGv85LlT0nOQOaiRY38mCeYE5Ct6pDgzd6HzP7LgcgwIdFi0uqj2Ahs/oxYsUWIJv2F5HsNcwfe4fSk03Pmhc5qoBqIvk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787650489; c=relaxed/simple; bh=UDYJRsAPl5fjz/VtHwbbxQfIjdEnUJVUfvLAT5IwNgc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=C6HUMLZWv768YZagQKKxzPVLIQ9GqxEfmSvnh5Um7TJjh6U6LSedjj7M6Qw2n+OGqvgqcAUAvT8gdW51abbYVxyvPKzlNaxvgYgR/GooWZKeKJCSzhBv6f9toRZqDLtBLdL8oL9EqErpM9nCm9GpgUkgN8p95HX+uq6hRMkKgho= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from DESKTOP-L0HPE2S.localdomain (unknown [36.110.52.2]) by APP-03 (Coremail) with SMTP id rQCowAC3vTuuYY1qbn46Bg--.38096S2; Tue, 25 Aug 2026 17:34:39 +0800 (CST) From: Haotian Zhang To: rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Haotian Zhang Subject: [PATCH 1/2] samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify Date: Tue, 25 Aug 2026 17:34:21 +0800 Message-ID: <20260825093421.7377-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:rQCowAC3vTuuYY1qbn46Bg--.38096S2 X-Coremail-Antispam: 1UD129KBjvJXoW7WrW5Xr18urW8Cr4fCw43GFg_yoW8Gw45p3 y7u3sxGr1rAFZ7KF9ruFyDCr17A347JrWUCas5A390vwnxurWUXryjyasIgF4xArWrtrW7 Zr4qyrWkJF45XaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkG14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWxJVW8Jr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWU AVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4U MIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUXeOJUUU UU= X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiBwIKA2qNI67uqwAAsj 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. Fixes: e1067a07cfbc ("ftrace/samples: Add module to test multi direct modify interface") Signed-off-by: Haotian Zhang --- samples/ftrace/ftrace-direct-multi-modify.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c index 8f7986d698d8..f339131654c7 100644 --- a/samples/ftrace/ftrace-direct-multi-modify.c +++ b/samples/ftrace/ftrace-direct-multi-modify.c @@ -364,8 +364,13 @@ static int __init ftrace_direct_multi_init(void) ret = register_ftrace_direct(&direct, my_tramp); - if (!ret) + if (!ret) { simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); + if (IS_ERR(simple_tsk)) { + unregister_ftrace_direct(&direct, my_tramp, true); + ret = PTR_ERR(simple_tsk); + } + } return ret; } -- 2.43.0