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=1792437842; b=QzJ2gIpO7ozKlA0HqO7vI3+3sbX+3P0ECOsyO3HYV0980JB21oIcxl/9lzuEinSuidtM AljFN6Z8L4tAE18ajCWVuxPecPApIiRDzDPqWLuPIvZYqF5mrGi5WHD4v4XD/tZPa/G0f ZlwZeOUEOKDevHa/pzJYpo4MEteF2FQ4D107TN3wvWtmKgP2YnuC3xeho02nnS8MMllSY 5/6lZbaE08yejSjuFU1AHcb9eJieXZaGZmQXXbnuA9GiGiXMih32pRgzYzXtlyXks5KJD X9hnpd8bb/THZnoVM+qwqrzRTW1V0/2STViVvTFEmgoegDk6qLwXGqlnjGO8WhFfGAQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792437842; h=Received:DKIM-Signature:Received:Message-ID:User-Agent:Date:From:To: Cc:Subject:References:MIME-Version:Content-Type; bh=qvo4bbQ/ofSmszMuiXKQj2CYkjAHtS+en8Odnv1yaQc=; b=HEb7yX1FUDUFXX/Vnwd+GrZE6WFn6y14lffOETTtGB8Wrdse7e81UDUGgNhDcB4+PJ1I X6p3/QsHF5Q+UlKc5fmYXVRIoZreLqMig5EcWgZ5x2o1IHgXpYwgnEOak1JwpPt82Ncs6 E5SPkWus/LOGRB49wLikoUn6DbicYMTNIDOam9WRCjmuw2nuI2VQkOmqMdN1PU5RE1zs2 LiKTenFNE+HBNmXXHYzid3IaRJd9/44s4tX90/xr0wdwsbypmW7VV0nmUZZueww2UoW2w YGmnlU+gayCoT3O04fDlg7PErr+tAWl0huDNIw9ScMNmI5rIU0lAje6wmThxNsfuF0Q== 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=nhGE3IOa; 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 D1C2B606A31F; Mon, 19 Oct 2026 19:24:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=nhGE3IOa Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB5131F000CD; Mon, 19 Oct 2026 19:24:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792437841; bh=qvo4bbQ/ofSmszMuiXKQj2CYkjAHtS+en8Odnv1yaQc=; h=Date:From:To:Cc:Subject:References; b=nhGE3IOa9e7MlwMMkSKbH8E+KHWEoKO7IgMbDUJOyMCNPE+VhKTgsTKtnwWwscMiq hCnWkd01Xqgag2SD2r8U98a6DSoL9yZWAhtNj+g14GNW8W+DcARG1ClTSkBKodtst/ 97jwaKz5snV3WAsQmHpMOjxBhDnP8x6SWGkiJ1kGo6c2mFfFBo7nq57NTb9g5tO4DN VkQ6qucrAqB6K0HNYeaGBjw0VC8GRpoXQgKiGpPTJ1HnR/uAaatAz1RyfCQnvt6CNr D+kgG4kIUU5h4iQpsUj23BaCm1jA9QAC11bstbty4VLblGk5xN7lcl80ykqGmKc+oy Y3yI9YIwsWbDQ== Received: from rostedt by gandalf with local (Exim 4.100.1) (envelope-from ) id 1xIsxk-00000001eJp-47N9; Mon, 19 Oct 2026 15:24:00 -0400 Message-ID: <20261019192400.787979601@kernel.org> User-Agent: quilt/0.69 Date: Mon, 19 Oct 2026 15:23:53 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, Gavin Inglis , Aaron Ahmed Subject: [for-next][PATCH 9/9] ftrace: Initialize modname and offset in print_rec() References: <20261019192344.004592683@kernel.org> 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 From: Aaron Ahmed print_rec() leaves 'modname' and 'offset' uninitialized and kallsyms_lookup() only sets them on success. When the lookup fails like when a module is being loaded or unloaded, 'modname' holds a garbage value, passes the 'if (modname)' check, and is dereferenced by seq_printf(). Oops: general protection fault RIP: 0010:string+0x48/0xe0 Call Trace: vsnprintf+0x1f5/0x650 seq_printf+0x8e/0xb0 print_rec+0x6c/0xc0 t_show+0x4c/0x440 seq_read_iter+0x119/0x480 This can be triggered by reading available_filter_functions while a module is being loaded or unloaded. Initialize both variables so a failed lookup skips the module name. Cc: stable@vger.kernel.org Fixes: b39181f7c690 ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function") Link: https://patch.msgid.link/20261016230403.4916-1-aarnahmd@amazon.com Tested-by: Gavin Inglis Signed-off-by: Aaron Ahmed Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b2597eb9581b..c7d74b33d36d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4431,9 +4431,9 @@ subsys_initcall(ftrace_check_for_weak_functions); static int print_rec(struct seq_file *m, unsigned long ip) { - unsigned long offset; + unsigned long offset = 0; char str[KSYM_SYMBOL_LEN]; - char *modname; + char *modname = NULL; const char *ret; ret = kallsyms_lookup(ip, NULL, &offset, &modname, str); -- 2.53.0