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Message-ID: <20250316125657.09ac3ec8@batman.local.home>
Date: Sun, 16 Mar 2025 12:56:57 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers
<mathieu.desnoyers@...icios.com>, Tengda Wu <wutengda@...weicloud.com>
Subject: [for-linus][PATCH] tracing: Correct the refcount if the
hist/hist_debug file fails to open
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace/fixes
Head SHA1: 0b4ffbe4888a2c71185eaf5c1a02dd3586a9bc04
Tengda Wu (1):
tracing: Correct the refcount if the hist/hist_debug file fails to open
----
kernel/trace/trace_events_hist.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
---------------------------
commit 0b4ffbe4888a2c71185eaf5c1a02dd3586a9bc04
Author: Tengda Wu <wutengda@...weicloud.com>
Date: Fri Mar 14 06:53:35 2025 +0000
tracing: Correct the refcount if the hist/hist_debug file fails to open
The function event_{hist,hist_debug}_open() maintains the refcount of
'file->tr' and 'file' through tracing_open_file_tr(). However, it does
not roll back these counts on subsequent failure paths, resulting in a
refcount leak.
A very obvious case is that if the hist/hist_debug file belongs to a
specific instance, the refcount leak will prevent the deletion of that
instance, as it relies on the condition 'tr->ref == 1' within
__remove_instance().
Fix this by calling tracing_release_file_tr() on all failure paths in
event_{hist,hist_debug}_open() to correct the refcount.
Cc: stable@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Zheng Yejian <zhengyejian1@...wei.com>
Link: https://lore.kernel.org/20250314065335.1202817-1-wutengda@huaweicloud.com
Fixes: 1cc111b9cddc ("tracing: Fix uaf issue when open the hist or hist_debug file")
Signed-off-by: Tengda Wu <wutengda@...weicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index ad7419e24055..53dc6719181e 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5689,12 +5689,16 @@ static int event_hist_open(struct inode *inode, struct file *file)
guard(mutex)(&event_mutex);
event_file = event_file_data(file);
- if (!event_file)
- return -ENODEV;
+ if (!event_file) {
+ ret = -ENODEV;
+ goto err;
+ }
hist_file = kzalloc(sizeof(*hist_file), GFP_KERNEL);
- if (!hist_file)
- return -ENOMEM;
+ if (!hist_file) {
+ ret = -ENOMEM;
+ goto err;
+ }
hist_file->file = file;
hist_file->last_act = get_hist_hit_count(event_file);
@@ -5702,9 +5706,14 @@ static int event_hist_open(struct inode *inode, struct file *file)
/* Clear private_data to avoid warning in single_open() */
file->private_data = NULL;
ret = single_open(file, hist_show, hist_file);
- if (ret)
+ if (ret) {
kfree(hist_file);
+ goto err;
+ }
+ return 0;
+err:
+ tracing_release_file_tr(inode, file);
return ret;
}
@@ -5979,7 +5988,10 @@ static int event_hist_debug_open(struct inode *inode, struct file *file)
/* Clear private_data to avoid warning in single_open() */
file->private_data = NULL;
- return single_open(file, hist_debug_show, file);
+ ret = single_open(file, hist_debug_show, file);
+ if (ret)
+ tracing_release_file_tr(inode, file);
+ return ret;
}
const struct file_operations event_hist_debug_fops = {
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