From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) (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 B52EA46AA68 for ; Tue, 4 Aug 2026 14:03:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785852236; cv=none; b=rDUVcetZCDkP1yy4r+2nxHlRyMHJf1G0eFVdkazPwo+et5zP/mYnaL2DVO+Ko5moSSkujJI7ZqQWcNC/lS3oWqgaKWMhvzJIpYizmdJ1C2W3UN0Qs8u+X9LmJmqolEf9/xHPbm192NGs7fn+2aW334osWu2Q2/5v38dt3K863o0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785852236; c=relaxed/simple; bh=6qDvctFwiRtQnW9hh5pPZSo3OigRO4Spf8WVxLaSAFY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HkD6yhvZvGwDLKs9uDT6RfxmeDNys+IWMJ3s4m3MULsXhjtSdCCVbgjFdeVf6OSB+D1ZNspWGe8ody6LeFDTWf6kqbvoEF72Bzzkp9Tyuo/K29Z/TSJqHV/NZbZZziDWN81HzSPw1QQBBcwBWKklefqZzfTa8ftGqwJV8uH8G64= 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=PQzycZa0; arc=none smtp.client-ip=209.85.128.72 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="PQzycZa0" Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-49571407d1dso23394315e9.0 for ; Tue, 04 Aug 2026 07:03:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785852233; x=1786457033; 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=+8opRsT5LzS+GIuqYDwGNkUMU0tmiiRh3ZQ9mQy9bPg=; b=PQzycZa0yA7r0jpZEGx2nKorTdXiR7KCVReL0uhH+Svqae3ce6urF0haHgjmA1z0KD 9j5R8fGmdbq1I1aEGVm6oEuw4A0E5wf6EqDLXRC8TtbojvuYpLjcsYMgLTWiqCJ12tWS CmAT9Tp1/Mg/9Ctx8i4A8SVlHJoLkKssohP06wVN6hMyDxxBxwmg7VScLwZuWsn+5cpy UfVtaaHzVsjmcKZnJoh0fbekCKw1rnBT9dL9bKH+LUJDLstoys2pp/fekTy5FDt6WEWA rtR6fEpvwgObf5K+8lnZ5d1psWnTEA61yPyS23V41ewHkwBXSqG3t0GMMSM2AZ5EyfBW 2n4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785852233; x=1786457033; 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=+8opRsT5LzS+GIuqYDwGNkUMU0tmiiRh3ZQ9mQy9bPg=; b=nuUlTlvAkRNjcVoLCdk92r8d6Q/aTwUB6NYyIS8wBmf8gyq/Zws2aBN7I5MGe2sf4P XcWUWOUYBRsy/j0tfyY2RjrjyexJh3WmFg+8whB1ARmLsQkmSSgeqK/cKNcm1CVc3ovd cwAUEgnKWNf+oZxdnZc2SiEM2Nqb08spm/Rv4ZuDu7OUtyYCu2ZGYSDuBOVGgUYjb/78 E4TlWq5od9cnqu/g73ibfFBPtIavFAsfNf0Vl9biYnJyj213Y5b/6X1I2rlUe8YODGq8 ed/4f6CbUzHz7HG6omhS0e0xaO0sUddnbyXIJasMqt9d/d8ez17ywUvKPp3kBTF2q58y YYEg== X-Forwarded-Encrypted: i=1; AHgh+RodyFCY0k4rFQCZdSasBSxndNWgt+6y4vsf6GMNWahmwSCJhXKlhwqgmhsDe0Eb5izCdVXLGy1FCAE5iQOpzMCPIxI=@vger.kernel.org X-Gm-Message-State: AOJu0Yylo+S5mrzXbnf7/AwySAZy2acnmZHrOdnk0JIBZfyGQxWhzrml lDC23cm95JUk0eLy17LXF0Dd0IzJy9GToLvgGVwR3Ik9qVo+lg/Md6kJiCMZPUDVnt8O1eaMZtZ A6kRBkuW1UiRTps0s2cLqjA== X-Received: from wmbhi18.prod.google.com ([2002:a05:600c:5352:b0:495:4728:580]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:6209:b0:495:6396:8b67 with SMTP id 5b1f17b1804b1-4980c649f67mr365562795e9.4.1785852232284; Tue, 04 Aug 2026 07:03:52 -0700 (PDT) Date: Tue, 4 Aug 2026 15:03:16 +0100 In-Reply-To: <20260804140333.797210-1-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: <20260804140333.797210-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.571.g244d577d93-goog Message-ID: <20260804140333.797210-2-vdonnefort@google.com> Subject: [PATCH v4 01/18] 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 diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index e6724f947170..ce2d517183b7 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; } @@ -1069,7 +1140,7 @@ 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) { @@ -1079,7 +1150,7 @@ 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) { @@ -1108,7 +1179,7 @@ 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) @@ -1194,6 +1265,7 @@ 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, }; @@ -1218,6 +1290,7 @@ 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, }; @@ -1241,6 +1314,7 @@ 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, }; -- 2.55.0.571.g244d577d93-goog