From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 187923803DE for ; Fri, 5 Jun 2026 16:39:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780677580; cv=none; b=e9OFyk6gbbr7MIooyFxXW3931hFL92NZgn1ANLIbvd3N+zxMhFY24am2LJRxDQpAzRaWiZ5f241h2v0zoRTI0iInKKsnzrYi8oe/33aMvpU3K9T+XupEYZs8+crCGm5DKSA/5EvYpF1YMeyo2aXfBEY1M5iCThf8yocLIymcWHI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780677580; c=relaxed/simple; bh=mK31nbR0GiGQSy13eS7gkZ308/tieE3Jjt0CJX3QeuM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=q3udpeINyP+4qmGKbV2yvXf7UfFEmlW52MAYaEDul1PoYkHdv3XygLRRKZyT9GiuWLKg/NBxcIpXU+uegN9u2zwe9OYqy4FBdiLOaC+zjAIgsebMa7CMu4gZA76v49On9ZsZRd1qx80+KKja4XaB1sc0ROHFKTCjxndip6a3HfE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=m03tagc6; arc=none smtp.client-ip=209.85.208.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="m03tagc6" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-68c39e36c29so1531053a12.3 for ; Fri, 05 Jun 2026 09:39:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780677575; x=1781282375; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=wOv8x0n5XQIlvXk2A8Ta+kM42ybcHPXg7v8d+5HE8u4=; b=m03tagc6G66IlQbjySOOtT7cd8z+h/0r8EEodCixaru8R/f0mCQQfixhk4TpPFlNf5 TcFMVRIuPG9KYrejlk/GWDHXPPXQpSpyq0il4nD5O+U/es5JLEMyIoEwFSzownmv97yg uVbpNUse/Ub8POlv77jJc/LjoVkv7/a4JWrsKicT4ZkQlnw9O7k/HcOTHwsxWU5nL3pP ZtDSxN7JNy1o+1SGiII4QPOdTlbimkbH8n0RM/r2daIfiYKiu/ew2Kora87IhOeSIJGL qs7UXzw2s9O2b5Pm7yvI53qRDc/v6ZdqewxbCNw+YqXNah+vb26bG2UnoIYgeGt1Au5G xWKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780677575; x=1781282375; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wOv8x0n5XQIlvXk2A8Ta+kM42ybcHPXg7v8d+5HE8u4=; b=bHZssKeqUCA8A65Y323o8ZnPAgFOmmuxZ82SeIx4GA6pjuCB+5y+7OsYdLjuzBCi4x qoG5PKCuNpk7GRsTAqZPt2jjP3hg42eEqaeFEjCZEB+1F1LOJJHYdtF200IAmZpmIA5h TTS7eYOEzqQxQiPFGSR9PoV742CtvmYX4JeGJavUxm3eM4bO/lC9+Ye5fH0FoNBhhQnt GK9IIPKxVceOF0S+GVBQpqiO1D+SOcMdoCliOvVBMf6jjqrqKUmi9uu5U+lbqXz+YbWZ +eVbCnjj3x/EL718yynba+6SVLN6Y6rnJCQiPFdm5VJvcKKRNVBnVi/lO4Id6rzbIJLi 6MPw== X-Forwarded-Encrypted: i=1; AFNElJ9kGK0RqG7nHn2Kam42za0+gzVty2R2is7dswuGZ6XHMIamL3wp2fwPmSyFXZEtY1QQ2wsGjsoPvIUJiE868V/lCig=@vger.kernel.org X-Gm-Message-State: AOJu0YznxTayTdqtc3MYdVDIUFT8i82eGlud+FP3bUJZU5w+kq7Y2jr/ Qwu/shMJEw12wMYxIxIjGfKXZyN+Jdyo7LJJVS+BZQcyhIT074I5cj//NVG7JdBF5NbbCTPRQ1U q9BwzqtNSt8aLjAOLMwGcvA== X-Received: from edbel13.prod.google.com ([2002:a05:6402:360d:b0:68d:63b5:158a]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a17:907:6d05:b0:bd9:cf0c:93c0 with SMTP id a640c23a62f3a-bf36fba1c62mr230741566b.1.1780677575018; Fri, 05 Jun 2026 09:39:35 -0700 (PDT) Date: Fri, 5 Jun 2026 17:38:08 +0100 In-Reply-To: <20260605163825.1762953-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260605163825.1762953-1-vdonnefort@google.com> X-Mailer: git-send-email 2.54.0.1032.g2f8565e1d1-goog Message-ID: <20260605163825.1762953-2-vdonnefort@google.com> Subject: [PATCH v2 01/18] tracing/remotes: Gate tracefs files opening on trace remote registration From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org Cc: kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" Currently, if a remote fails to register, its resources will leak and will not be properly tear-downed. To prevent a user accessing a remote tracefs that is about to be destroyed, keep track of the registered remotes in a global list, similarly to trace instances. Gate the tracefs to open function based on the presence of the remote in that list. Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index d6c3f94d67cd..9f1669d433d5 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -39,6 +39,7 @@ struct trace_remote_iterator { }; struct trace_remote { + struct list_head node; struct trace_remote_callbacks *cbs; void *priv; struct trace_buffer *trace_buffer; @@ -57,6 +58,9 @@ struct trace_remote { bool tracing_on; }; +static DEFINE_MUTEX(trace_remotes_lock); +static LIST_HEAD(trace_remotes); + static bool trace_remote_loaded(struct trace_remote *remote) { return !!remote->trace_buffer; @@ -170,6 +174,60 @@ static void trace_remote_reset(struct trace_remote *remote, int cpu) trace_remote_try_unload(remote); } +static int trace_remote_tracefs_open(struct inode *inode, struct file *filp) +{ + void *i_private = inode->i_private; + struct trace_remote *r; + + if (!i_private) + return -ENODEV; + + guard(mutex)(&trace_remotes_lock); + + /* i_private is either a struct trace_remote or a struct remote_event */ + list_for_each_entry(r, &trace_remotes, node) { + if (r == i_private) + return 0; + if (!r->events) + continue; + if (i_private >= (void *)r->events && + i_private < (void *)(r->events + r->nr_events)) + return 0; + } + + return -ENODEV; +} + +#define DEFINE_TRACE_REMOTE_ATTRIBUTE_FUNCS(__name) \ +static int __name ## _open(struct inode *inode, struct file *file) \ +{ \ + int ret = trace_remote_tracefs_open(inode, file); \ + \ + if (ret) \ + return ret; \ + \ + return single_open(file, __name ## _show, inode->i_private); \ +} + +#define DEFINE_TRACE_REMOTE_ATTRIBUTE(__name) \ +DEFINE_TRACE_REMOTE_ATTRIBUTE_FUNCS(__name) \ +static const struct file_operations __name ## _fops = { \ + .open = __name ## _open, \ + .read = seq_read, \ + .write = __name ## _write, \ + .llseek = seq_lseek, \ + .release = single_release, \ +} + +#define DEFINE_TRACE_REMOTE_SHOW_ATTRIBUTE(__name) \ +DEFINE_TRACE_REMOTE_ATTRIBUTE_FUNCS(__name) \ +static const struct file_operations __name ## _fops = { \ + .open = __name ## _open, \ + .read = seq_read, \ + .llseek = seq_lseek, \ + .release = single_release, \ +} + static ssize_t tracing_on_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { @@ -198,7 +256,7 @@ static int tracing_on_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_STORE_ATTRIBUTE(tracing_on); +DEFINE_TRACE_REMOTE_ATTRIBUTE(tracing_on); static ssize_t buffer_size_kb_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) @@ -235,7 +293,7 @@ static int buffer_size_kb_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_STORE_ATTRIBUTE(buffer_size_kb); +DEFINE_TRACE_REMOTE_ATTRIBUTE(buffer_size_kb); static int trace_remote_get(struct trace_remote *remote, int cpu) { @@ -593,6 +651,11 @@ static int trace_pipe_open(struct inode *inode, struct file *filp) struct trace_remote *remote = inode->i_private; struct trace_remote_iterator *iter; int cpu = tracing_get_cpu(inode); + int ret; + + ret = trace_remote_tracefs_open(inode, filp); + if (ret) + return ret; guard(mutex)(&remote->lock); @@ -602,7 +665,7 @@ static int trace_pipe_open(struct inode *inode, struct file *filp) filp->private_data = iter; - return IS_ERR(iter) ? PTR_ERR(iter) : 0; + return 0; } static int trace_pipe_release(struct inode *inode, struct file *filp) @@ -734,22 +797,26 @@ static int trace_open(struct inode *inode, struct file *filp) int cpu = tracing_get_cpu(inode); int ret; + ret = trace_remote_tracefs_open(inode, filp); + if (ret) + return ret; + if (!(filp->f_mode & FMODE_READ)) return 0; + ret = seq_open(filp, &trace_sops); + if (ret) + return ret; + guard(mutex)(&remote->lock); iter = trace_remote_iter(remote, cpu, TRI_NONCONSUMING); - if (IS_ERR(iter)) + if (IS_ERR(iter)) { + seq_release(inode, filp); return PTR_ERR(iter); - - ret = seq_open(filp, &trace_sops); - if (ret) { - trace_remote_iter_free(iter); - return ret; } - ((struct seq_file *)filp->private_data)->private = (void *)iter; + ((struct seq_file *)filp->private_data)->private = iter; return 0; } @@ -932,8 +999,12 @@ int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, } ret = cbs->init ? cbs->init(remote->dentry, priv) : 0; - if (ret) + if (ret) { pr_err("Init failed for trace remote '%s' (%d)\n", name, ret); + } else { + guard(mutex)(&trace_remotes_lock); + list_add(&remote->node, &trace_remotes); + } return ret; } @@ -1076,7 +1147,7 @@ static ssize_t remote_event_enable_write(struct file *filp, const char __user *u return count; } -DEFINE_SHOW_STORE_ATTRIBUTE(remote_event_enable); +DEFINE_TRACE_REMOTE_ATTRIBUTE(remote_event_enable); static int remote_event_id_show(struct seq_file *s, void *unused) { @@ -1086,7 +1157,7 @@ static int remote_event_id_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_ATTRIBUTE(remote_event_id); +DEFINE_TRACE_REMOTE_SHOW_ATTRIBUTE(remote_event_id); static int remote_event_format_show(struct seq_file *s, void *unused) { @@ -1115,7 +1186,7 @@ static int remote_event_format_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_ATTRIBUTE(remote_event_format); +DEFINE_TRACE_REMOTE_SHOW_ATTRIBUTE(remote_event_format); static int remote_event_callback(const char *name, umode_t *mode, void **data, const struct file_operations **fops) @@ -1190,6 +1261,7 @@ static ssize_t remote_events_dir_enable_read(struct file *filp, char __user *ubu } static const struct file_operations remote_events_dir_enable_fops = { + .open = trace_remote_tracefs_open, .write = remote_events_dir_enable_write, .read = remote_events_dir_enable_read, }; @@ -1214,6 +1286,7 @@ remote_events_dir_header_page_read(struct file *filp, char __user *ubuf, size_t } static const struct file_operations remote_events_dir_header_page_fops = { + .open = trace_remote_tracefs_open, .read = remote_events_dir_header_page_read, }; @@ -1237,6 +1310,7 @@ remote_events_dir_header_event_read(struct file *filp, char __user *ubuf, size_t } static const struct file_operations remote_events_dir_header_event_fops = { + .open = trace_remote_tracefs_open, .read = remote_events_dir_header_event_read, }; -- 2.54.0.1032.g2f8565e1d1-goog