From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out28-123.mail.aliyun.com (out28-123.mail.aliyun.com [115.124.28.123]) (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 B9C4B345725; Mon, 10 Aug 2026 06:32:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.28.123 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786343564; cv=none; b=K9l4+UBnTuf1aicOlG5ijlooFdA/BEiuj0cw3rZcQN/te+DZkvRm2WmKaKPoOAcPv34scI6I4CWDwTVjiRtPMYc0SZFVkaxcLq26onIrkIsVixnRADCmowOClO4bVrF8IiT1cw31oKsB2NfX5I1aGfP8JT6eoSqaua4TeSElodo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786343564; c=relaxed/simple; bh=27k1X9vAM1qMy4wwY7ziUz5/u+StbIUNBHGh0LN5BKs=; h=Message-ID:Date:MIME-Version:To:Cc:From:Subject:Content-Type; b=qwEtx5eRjKk01litHgAZwJLenStizBVKFaedQO+fNKQwKmFEKyscgnEYITmsnefiJEV5POsdNJMtSp7lnMoJGkRsXEArfaGDo0QMxJAZnNP4lD9bnXerijb252sX4gZE/VEpM+aGqA4QBoam2NJWfYJw0lA1/5aVSWQE81ksF5s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=allwinnertech.com; spf=pass smtp.mailfrom=allwinnertech.com; arc=none smtp.client-ip=115.124.28.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=allwinnertech.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=allwinnertech.com X-Alimail-AntiSpam:AC=CONTINUE;BC=0.1086931|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_enroll_verification|0.0119426-0.031275-0.956782;FP=13247847429411803131|0|0|0|0|-1|-1|-1;HT=maildocker-contentspam033037025160;MF=michael@allwinnertech.com;NM=1;PH=DS;RN=5;RT=5;SR=0;TI=SMTPD_---.iiCXqdE_1786343550; Received: from 192.168.208.183(mailfrom:michael@allwinnertech.com fp:SMTPD_---.iiCXqdE_1786343550 cluster:ay29) by smtp.aliyun-inc.com; Mon, 10 Aug 2026 14:32:31 +0800 Message-ID: <2e5730d2-c631-da41-3a3a-ae35bb4895f3@allwinnertech.com> Date: Mon, 10 Aug 2026 14:32:30 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Content-Language: en-US To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org From: Michael Wu Subject: [PATCH v5] tracing: Fix race between update_event_fields and, event_define_fields Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit The following sequence may leads race between event_define_fields() and update_event_fields(): CPU0 (module A, pri=1 notifier) CPU1 (module B, pri=0 notifier) =============================== =============================== event_define_fields(call_A) trace_event_update_all() for each f: list_for_each_entry(..., list_add(&f->link, &ftrace_events) &class->fields) -> finds call_A f->link.next = next; (2) update_event_fields(call_A) WRITE_ONCE(class->fields->next, &f->link); (4) list_for_each_entry(field, &class->fields, link) -> field = class->fields->next = &f->link = f (offset 0) -> arm64 weak ordering: (4) visible before (2) field->link.next == 0 -> next iteration: field = (void *)0 = NULL -> crash at NULL->type (0x18) This produces the following panic: Unable to handle kernel access ... at virtual address 0000000000000018 pc : update_event_fields+0xf8/0x368 Call trace: update_event_fields+0xf8/0x368 trace_event_update_all+0x7c/0x2b4 trace_module_notify+0x4c/0x1dc notifier_call_chain+0x84/0x168 blocking_notifier_call_chain_robust+0x64/0xd4 load_module+0x10c8/0x123c __arm64_sys_finit_module+0x230/0x31c Fix by taking event_mutex in trace_event_update_all() before trace_event_sem. Fixes: b3bc8547d3be ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well") Cc: stable@vger.kernel.org Signed-off-by: Michael Wu --- kernel/trace/trace_events.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 956692856fa8..9632788da5af 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3566,6 +3566,7 @@ void trace_event_update_all(struct trace_eval_map **map, int len) int last_i; int i; + mutex_lock(&event_mutex); down_write(&trace_event_sem); list_for_each_entry_safe(call, p, &ftrace_events, list) { /* events are usually grouped together with systems */ @@ -3604,6 +3605,7 @@ void trace_event_update_all(struct trace_eval_map **map, int len) cond_resched(); } up_write(&trace_event_sem); + mutex_unlock(&event_mutex); } static bool event_in_systems(struct trace_event_call *call, -- 2.29.0