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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ajay Kaher <akaher@vmware.com>,
	Zheng Yejian <zhengyejian1@huawei.com>,
	Naresh Kamboju <naresh.kamboju@linaro.org>
Subject: [for-linus][PATCH 10/15] tracefs/eventfs: Free top level files on removal
Date: Fri, 08 Sep 2023 23:16:25 -0400	[thread overview]
Message-ID: <20230909032350.061257707@goodmis.org> (raw)
In-Reply-To: <20230909031615.047488015@goodmis.org>

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

When an instance is removed, the top level files of the eventfs directory
are not cleaned up. Call the eventfs_remove() on each of the entries to
free them.

This was found via kmemleak:

unreferenced object 0xffff8881047c1280 (size 96):
  comm "mkdir", pid 924, jiffies 4294906489 (age 2013.077s)
  hex dump (first 32 bytes):
    18 31 ed 03 81 88 ff ff 00 31 09 24 81 88 ff ff  .1.......1.$....
    00 00 00 00 00 00 00 00 98 19 7c 04 81 88 ff ff  ..........|.....
  backtrace:
    [<000000000fa46b4d>] kmalloc_trace+0x2a/0xa0
    [<00000000e729cd0c>] eventfs_prepare_ef.constprop.0+0x3a/0x160
    [<000000009032e6a8>] eventfs_add_events_file+0xa0/0x160
    [<00000000fe968442>] create_event_toplevel_files+0x6f/0x130
    [<00000000e364d173>] event_trace_add_tracer+0x14/0x140
    [<00000000411840fa>] trace_array_create_dir+0x52/0xf0
    [<00000000967804fa>] trace_array_create+0x208/0x370
    [<00000000da505565>] instance_mkdir+0x6b/0xb0
    [<00000000dc1215af>] tracefs_syscall_mkdir+0x5b/0x90
    [<00000000a8aca289>] vfs_mkdir+0x272/0x380
    [<000000007709b242>] do_mkdirat+0xfc/0x1d0
    [<00000000c0b6d219>] __x64_sys_mkdir+0x78/0xa0
    [<0000000097b5dd4b>] do_syscall_64+0x3f/0x90
    [<00000000a3f00cfa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
unreferenced object 0xffff888103ed3118 (size 8):
  comm "mkdir", pid 924, jiffies 4294906489 (age 2013.077s)
  hex dump (first 8 bytes):
    65 6e 61 62 6c 65 00 00                          enable..
  backtrace:
    [<0000000010f75127>] __kmalloc_node_track_caller+0x51/0x160
    [<000000004b3eca91>] kstrdup+0x34/0x60
    [<0000000050074d7a>] eventfs_prepare_ef.constprop.0+0x53/0x160
    [<000000009032e6a8>] eventfs_add_events_file+0xa0/0x160
    [<00000000fe968442>] create_event_toplevel_files+0x6f/0x130
    [<00000000e364d173>] event_trace_add_tracer+0x14/0x140
    [<00000000411840fa>] trace_array_create_dir+0x52/0xf0
    [<00000000967804fa>] trace_array_create+0x208/0x370
    [<00000000da505565>] instance_mkdir+0x6b/0xb0
    [<00000000dc1215af>] tracefs_syscall_mkdir+0x5b/0x90
    [<00000000a8aca289>] vfs_mkdir+0x272/0x380
    [<000000007709b242>] do_mkdirat+0xfc/0x1d0
    [<00000000c0b6d219>] __x64_sys_mkdir+0x78/0xa0
    [<0000000097b5dd4b>] do_syscall_64+0x3f/0x90
    [<00000000a3f00cfa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Link: https://lore.kernel.org/linux-trace-kernel/20230907175859.6fedbaa2@gandalf.local.home

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 5bdcd5f5331a2 eventfs: ("Implement removal of meta data from eventfs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 fs/tracefs/event_inode.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 609ccb5b7cfc..f168aca45458 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -195,17 +195,39 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
 {
 	struct tracefs_inode *ti_parent;
 	struct eventfs_inode *ei;
-	struct eventfs_file *ef;
-
-	mutex_lock(&eventfs_mutex);
+	struct eventfs_file *ef, *tmp;
 
 	/* The top level events directory may be freed by this */
 	if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) {
+		LIST_HEAD(ef_del_list);
+
+		mutex_lock(&eventfs_mutex);
+
 		ei = ti->private;
+
+		/* Record all the top level files */
+		list_for_each_entry_srcu(ef, &ei->e_top_files, list,
+					 lockdep_is_held(&eventfs_mutex)) {
+			list_add_tail(&ef->del_list, &ef_del_list);
+		}
+
+		/* Nothing should access this, but just in case! */
+		ti->private = NULL;
+
+		mutex_unlock(&eventfs_mutex);
+
+		/* Now safely free the top level files and their children */
+		list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
+			list_del(&ef->del_list);
+			eventfs_remove(ef);
+		}
+
 		kfree(ei);
-		goto out;
+		return;
 	}
 
+	mutex_lock(&eventfs_mutex);
+
 	ti_parent = get_tracefs(dentry->d_parent->d_inode);
 	if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE))
 		goto out;
-- 
2.40.1

  parent reply	other threads:[~2023-09-09  3:24 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-09  3:16 [for-linus][PATCH 00/15] tracing: Fixes for 6.6 Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 01/15] tracefs: Add missing lockdown check to tracefs_create_dir() Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 02/15] tracefs/eventfs: Add missing lockdown checks Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 03/15] tracefs/eventfs: Use dput to free the toplevel events directory Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 04/15] tracing: Increase trace array ref count on enable and filter files Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 05/15] tracing: Have tracing_max_latency inc the trace array ref count Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 06/15] tracing: Have current_trace " Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 07/15] tracing: Have option files " Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 08/15] tracing: Have event inject " Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 09/15] ring-buffer: Avoid softlockup in ring_buffer_resize() Steven Rostedt
2023-09-09  3:16 ` Steven Rostedt [this message]
2023-09-09  3:16 ` [for-linus][PATCH 11/15] ring-buffer: Do not attempt to read past "commit" Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 12/15] tracing: Use the new eventfs descriptor for print trigger Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 13/15] tracing: Remove unused trace_event_file dir field Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 14/15] selftests/ftrace: Fix dependencies for some of the synthetic event tests Steven Rostedt
2023-09-09  3:16 ` [for-linus][PATCH 15/15] tracing/synthetic: Fix order of struct trace_dynamic_info Steven Rostedt

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