From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756946Ab3G3Ldd (ORCPT ); Tue, 30 Jul 2013 07:33:33 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:26931 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753385Ab3G3Lby (ORCPT ); Tue, 30 Jul 2013 07:31:54 -0400 X-Authority-Analysis: v=2.0 cv=KJ7Y/S5o c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=CVlx3W2nY-cA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=bywy1vxgP7UA:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=3nbZYyFuAAAA:8 a=AAvYLDLOAAAA:8 a=ul9NfeeRlprL3ozlsnUA:9 a=jEp0ucaQiEUA:10 a=EvKJbDF4Ut8A:10 a=jeBq3FmKZ4MA:10 a=s2loLT2QvaoA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130730113152.994455018@goodmis.org> User-Agent: quilt/0.60-1 Date: Tue, 30 Jul 2013 07:27:24 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Frederic Weisbecker , Andrew Morton , Masami Hiramatsu , Oleg Nesterov Subject: [for-next-3.11][PATCH 6/8] tracing: Change remove_event_file_dir() to clear "d_subdirs"->i_private References: <20130730112718.273490378@goodmis.org> Content-Disposition: inline; filename=0006-tracing-Change-remove_event_file_dir-to-clear-d_subd.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleg Nesterov 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 Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 47 ++++++++++++++----------------------------- 1 file 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, }; -- 1.7.10.4