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author | Oleg Nesterov <oleg@redhat.com> | 2013-07-28 20:35:27 +0200 |
---|---|---|
committer | Steven Rostedt <rostedt@goodmis.org> | 2013-07-29 22:57:11 -0400 |
commit | bf682c3159c4d298d1126a56793ed3f5e80395f7 (patch) | |
tree | 119fe382412dbb356ded3bd708f93e8fae86550c /kernel | |
parent | f6a84bdc75b5c11621dec58db73fe102cbaf40cc (diff) | |
download | op-kernel-dev-bf682c3159c4d298d1126a56793ed3f5e80395f7.zip op-kernel-dev-bf682c3159c4d298d1126a56793ed3f5e80395f7.tar.gz |
tracing: Change remove_event_file_dir() to clear "d_subdirs"->i_private
Change remove_event_file_dir() to clear ->i_private for every
file we are going to remove.
We need to check file->dir != NULL because event_create_dir()
can fail. debugfs_remove_recursive(NULL) is fine but the patch
moves it under the same check anyway for readability.
spin_lock(d_lock) and "d_inode != NULL" check are not needed
afaics, but I do not understand this code enough.
tracing_open_generic_file() and tracing_release_generic_file()
can go away, ftrace_enable_fops and ftrace_event_filter_fops()
use tracing_open_generic() but only to check tracing_disabled.
This fixes all races with event_remove() or instance_delete().
f_op->read/write/whatever can never use the freed file/call,
all event/* files were changed to check and use ->i_private
under event_mutex.
Note: this doesn't not fix other problems, event_remove() can
destroy the active ftrace_event_call, we need more changes but
those changes are completely orthogonal.
Link: http://lkml.kernel.org/r/20130728183527.GB16723@redhat.com
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/trace_events.c | 47 |
1 files changed, 15 insertions, 32 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 05d647e..a67c913 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -428,42 +428,26 @@ static void *event_file_data(struct file *filp) static void remove_event_file_dir(struct ftrace_event_file *file) { + struct dentry *dir = file->dir; + struct dentry *child; + + if (dir) { + spin_lock(&dir->d_lock); /* probably unneeded */ + list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) { + if (child->d_inode) /* probably unneeded */ + child->d_inode->i_private = NULL; + } + spin_unlock(&dir->d_lock); + + debugfs_remove_recursive(dir); + } + list_del(&file->list); - debugfs_remove_recursive(file->dir); remove_subsystem(file->system); kmem_cache_free(file_cachep, file); } /* - * Open and update trace_array ref count. - * Must have the current trace_array passed to it. - */ -static int tracing_open_generic_file(struct inode *inode, struct file *filp) -{ - struct ftrace_event_file *file = inode->i_private; - struct trace_array *tr = file->tr; - int ret; - - if (trace_array_get(tr) < 0) - return -ENODEV; - - ret = tracing_open_generic(inode, filp); - if (ret < 0) - trace_array_put(tr); - return ret; -} - -static int tracing_release_generic_file(struct inode *inode, struct file *filp) -{ - struct ftrace_event_file *file = inode->i_private; - struct trace_array *tr = file->tr; - - trace_array_put(tr); - - return 0; -} - -/* * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events. */ static int @@ -1281,10 +1265,9 @@ static const struct file_operations ftrace_set_event_fops = { }; static const struct file_operations ftrace_enable_fops = { - .open = tracing_open_generic_file, + .open = tracing_open_generic, .read = event_enable_read, .write = event_enable_write, - .release = tracing_release_generic_file, .llseek = default_llseek, }; |