From d508ee2dd5574b1e84d140b927c25807c9b66d7e Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Thu, 7 Sep 2023 17:58:59 -0400 Subject: tracefs/eventfs: Free top level files on removal 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 Cc: Ajay Kaher Cc: Zheng Yejian Cc: Naresh Kamboju Reviewed-by: Masami Hiramatsu (Google) Fixes: 5bdcd5f5331a2 eventfs: ("Implement removal of meta data from eventfs") Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/event_inode.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) (limited to 'fs/tracefs') 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; -- cgit v1.2.3