From 17627157cda13089d8a6c1c2d35acb07334b899c Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Wed, 8 Feb 2017 14:28:55 +0300 Subject: kernfs: handle null pointers while printing node name and path Null kernfs nodes could be found at cgroups during construction. It seems safer to handle these null pointers right in kernfs in the same way as printf prints "(null)" for null pointer string. Signed-off-by: Konstantin Khlebnikov Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- include/trace/events/cgroup.h | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) (limited to 'include/trace') diff --git a/include/trace/events/cgroup.h b/include/trace/events/cgroup.h index ab68640a18d0..c226f50e88fa 100644 --- a/include/trace/events/cgroup.h +++ b/include/trace/events/cgroup.h @@ -61,19 +61,15 @@ DECLARE_EVENT_CLASS(cgroup, __field( int, id ) __field( int, level ) __dynamic_array(char, path, - cgrp->kn ? cgroup_path(cgrp, NULL, 0) + 1 - : strlen("(null)")) + cgroup_path(cgrp, NULL, 0) + 1) ), TP_fast_assign( __entry->root = cgrp->root->hierarchy_id; __entry->id = cgrp->id; __entry->level = cgrp->level; - if (cgrp->kn) - cgroup_path(cgrp, __get_dynamic_array(path), - __get_dynamic_array_len(path)); - else - __assign_str(path, "(null)"); + cgroup_path(cgrp, __get_dynamic_array(path), + __get_dynamic_array_len(path)); ), TP_printk("root=%d id=%d level=%d path=%s", @@ -119,8 +115,7 @@ DECLARE_EVENT_CLASS(cgroup_migrate, __field( int, dst_id ) __field( int, dst_level ) __dynamic_array(char, dst_path, - dst_cgrp->kn ? cgroup_path(dst_cgrp, NULL, 0) + 1 - : strlen("(null)")) + cgroup_path(dst_cgrp, NULL, 0) + 1) __field( int, pid ) __string( comm, task->comm ) ), @@ -129,11 +124,8 @@ DECLARE_EVENT_CLASS(cgroup_migrate, __entry->dst_root = dst_cgrp->root->hierarchy_id; __entry->dst_id = dst_cgrp->id; __entry->dst_level = dst_cgrp->level; - if (dst_cgrp->kn) - cgroup_path(dst_cgrp, __get_dynamic_array(dst_path), - __get_dynamic_array_len(dst_path)); - else - __assign_str(dst_path, "(null)"); + cgroup_path(dst_cgrp, __get_dynamic_array(dst_path), + __get_dynamic_array_len(dst_path)); __entry->pid = task->pid; __assign_str(comm, task->comm); ), -- cgit v1.2.3