From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.221.69 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793988465; b=TL6rNk8DR8VAVrFeOulK+nHMjm6rqRj1vuKv3rBL0iYt/alNrzjcNxfG8EBbp99B+4Sv 1OLQIfEXk5Ix5GRCFhtXX/w++SFQdiMw15SO0eUe0SCDXcCQKrkmrtrLYveNJhBq5FXQL IzBFwaTai+CE+wxSt5BT4x33RfFDFSvpLFB7S0ZAFcObu9q2boHddLoFqN3DC6zCT9cY0 HsOES6one7iDV5SVAiCwY2q140mJAHpfNhT19gVO9uYZSxKoPtjiDiCmpcfA9gyzpyxkM RVjbmNk8s6ICossZaI/00rdIEftQupqtg/aZBclMw7hfKP0o5BxC74GK4FvnPEaF4Aw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793988465; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Received:Date:In-Reply-To: Mime-Version:References:X-Mailer:Message-ID:Subject:From:To:Cc: Content-Type; bh=9VpW2XcWLKAq/ot4di2VXzHiKutqIoaszfzzAa09OfQ=; b=n9Rf8FkJTMeLnhYOP+BfXSu7x3dzZNTS8LHFGMW1NRtqkw6zePmFHWArnUn19yHEnhzw mdWDKtcZt1lamoAAqpxh12W0DEmlttZSwr5uMJO8ib4c55jvaKZ/8xLge4fvAyDyfm3Ej pbNAj8YfFkcITZizA5d64rDpfAfDVO5oMPuXGElrcWOjUzMhA8zg6ULy4L6WsfNoEbG3U N73rPI+sTMvTU1FYkE4pXwYSH0SQ+hVp8JXMqbRmVd8Aqy/148AUmsz07eiBC4Ce8D6Tv dznhMWKIjYz3PLq7kRcH3SA8HM/K2sptHvxHvbkjIXknT5/FEP1afzoTcvgz5fSooRQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=SVRd+Vz4; arc=none smtp.remote-ip=209.85.221.69 Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3D21F606A330 for ; Fri, 6 Nov 2026 18:07:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3D21F606A330 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, unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=SVRd+Vz4 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-48c6a1d4034so926809f8f.0 for ; Fri, 06 Nov 2026 10:07:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20260707; t=1793988463; x=1794593263; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=9VpW2XcWLKAq/ot4di2VXzHiKutqIoaszfzzAa09OfQ=; b=SVRd+Vz4ko2zP5XW9XiOLpFEgyOFctwAtAKOh9nV5lG+v1zd3qg6uhspgX/gH3lA/I ieIV5wu66fjRMCoScQbofAm6lA/LnZTI44ix0tTt1rIO/55Z546+4ksTmd70csD+5txH kK0iZWNWDrZl91IVbyAhNvVwWKIyW63vr1QmZhTtO3mxG7l0o1ZDF1kda8DonRKDQpoG ukwqYK+E7BTAkq4APLXFmWDy23gvykOtvnxSztQ+5Bib+GwMM/YP0DhUC9Z+4I0wQKxk KeL49nM2X+9nS4xB9duk6e85O1DExDEvr3PfuKsxw6B1VGqRML+0lNCtJ3sXpKMLGQ1k IDpA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793988463; x=1794593263; h=content-type: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:content-type; bh=9VpW2XcWLKAq/ot4di2VXzHiKutqIoaszfzzAa09OfQ=; b=1tNO9aeHi2veQU069Vk4FnrAbdRSSTtTvsMQy67EVg88rycKHw6YqHG+T1ZkYMJGfy sotAo2mwwF/T9bB2KAaTS3LkNDMKQhjHm4a+vFgoU97k5lqgugrqdQqQsdK0sH3ldOv0 56uA7gE7VEczWyNXRLKD6vMuD39cBNmSbj0JlW6S4GGKotZhRTC1kZzNktpZkIk+WDZK 8vd/yTuWME7dmNZ6jpATxzbD7SlbHkfyjM7Q9UNJikrWu2+KwpiFWmak6BwSo5D8dcQD 6ECDVI9N0YajCZDtVD8Ij0apD8qs9UyJIVqMMxEYUNNRWnG/IiiR6ielAImOakcofbbA sqAQ== X-Forwarded-Encrypted: i=1; AL+hErGYJIDyF3fSLyzsyXrVEpbge/4tzxq7mfNApa8uWIoT0Syjgxg+GNmVVHNBlHlLrDasdOeNzy3B4mywrZFLVCkRipQ=@vger.kernel.org X-Gm-Message-State: APuU4Z8M3b4AnRAHqLRXYLa8tdCpkGTPHj55Mt5Cf+NwFA5dIwqJKMH7 OSzzeGQYehAFvU7/SdxN70iwFX7k+8qiTjTw1znj9rq0ezoXAZPgw86I4G2Jp7XZNYAXHJIl/li /DUE7dTUrzDZ6iWO8CKXNJg== X-Received: from wrwy2.prod.google.com ([2002:a05:6000:1082:b0:48e:596:f6cd]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:25f3:b0:48b:1c:d6e1 with SMTP id ffacd0b85a97d-49277abcdb7mr6666871f8f.43.1793988463508; Fri, 06 Nov 2026 10:07:43 -0800 (PST) Date: Fri, 6 Nov 2026 18:06:37 +0000 In-Reply-To: <20261106180657.2460376-1-vdonnefort@google.com> X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 References: <20261106180657.2460376-1-vdonnefort@google.com> X-Mailer: git-send-email 2.56.0.455.g6c5a503b38-goog Message-ID: <20261106180657.2460376-2-vdonnefort@google.com> Subject: [PATCH v8 01/21] tracing/remotes: Gate tracefs files opening on trace remote registration From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, 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 torn down. 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 open function based on the presence of the remote in that list. Signed-off-by: Vincent Donnefort --- kernel/trace/trace_remote.c | 100 +++++++++++++++++++++++++++++++----- 1 file changed, 87 insertions(+), 13 deletions(-) diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index 2d5bc423efca..e8cbbd01964d 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); @@ -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; } @@ -1073,7 +1144,7 @@ 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) { @@ -1083,7 +1154,7 @@ 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) { @@ -1112,7 +1183,7 @@ 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) @@ -1198,6 +1269,7 @@ 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, }; @@ -1222,6 +1294,7 @@ 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, }; @@ -1245,6 +1318,7 @@ 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, }; -- 2.56.0.455.g6c5a503b38-goog