From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755569Ab0INU3N (ORCPT ); Tue, 14 Sep 2010 16:29:13 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:46449 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753469Ab0INU3K (ORCPT ); Tue, 14 Sep 2010 16:29:10 -0400 X-Authority-Analysis: v=1.1 cv=8l6A00wGdfxWf8DimOOtudg6dZOi9rXZmlWhmOLJpog= c=1 sm=0 a=GJHq10ptLZwA:10 a=bbbx4UPp9XUA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=20KFwNOVAAAA:8 a=xn_2uDM6AAAA:8 a=meVymXHHAAAA:8 a=TzR3T3odkhCL-pDeDdoA:9 a=fgLjTrBXmUAcrWVg9KIA:7 a=eoX4yFmLR0xZMHXTvNATthpeNe0A:4 a=jEp0ucaQiEUA:10 a=AlnqcuNMsHEA:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Message-Id: <20100914202842.597441667@goodmis.org> User-Agent: quilt/0.48-1 Date: Tue, 14 Sep 2010 16:27:16 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Chris Wright Subject: [PATCH 2/4] tracing: Replace typecasted void pointer in set_ftrace_filter code References: <20100914202714.376849326@goodmis.org> Content-Disposition: inline; filename=0002-tracing-Replace-typecasted-void-pointer-in-set_ftrac.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt The set_ftrace_filter uses seq_file and reads from two lists. The pointer returned by t_next() can either be of type struct dyn_ftrace or struct ftrace_func_probe. If there is a bug (there was one) the wrong pointer may be used and the reference can cause an oops. This patch makes t_next() and friends only return the iterator structure which now has a pointer of type struct dyn_ftrace and struct ftrace_func_probe. The t_show() can now test if the pointer is NULL or not and if the pointer exists, it is guaranteed to be of the correct type. Now if there's a bug, only wrong data will be shown but not an oops. Cc: Chris Wright Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 67 +++++++++++++++++++++++++++++++++--------------- 1 files changed, 46 insertions(+), 21 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 585ea27..c8db0db 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1368,25 +1368,29 @@ enum { #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ struct ftrace_iterator { - loff_t func_pos; - struct ftrace_page *pg; - int hidx; - int idx; - unsigned flags; - struct trace_parser parser; + loff_t func_pos; + struct ftrace_page *pg; + struct dyn_ftrace *func; + struct ftrace_func_probe *probe; + struct trace_parser parser; + int hidx; + int idx; + unsigned flags; }; static void * -t_hash_next(struct seq_file *m, void *v, loff_t *pos) +t_hash_next(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; - struct hlist_node *hnd = v; + struct hlist_node *hnd = NULL; struct hlist_head *hhd; WARN_ON(!(iter->flags & FTRACE_ITER_HASH)); (*pos)++; + if (iter->probe) + hnd = &iter->probe->node; retry: if (iter->hidx >= FTRACE_FUNC_HASHSIZE) return NULL; @@ -1409,7 +1413,12 @@ t_hash_next(struct seq_file *m, void *v, loff_t *pos) } } - return hnd; + if (WARN_ON_ONCE(!hnd)) + return NULL; + + iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node); + + return iter; } static void *t_hash_start(struct seq_file *m, loff_t *pos) @@ -1428,19 +1437,24 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos) iter->hidx = 0; for (l = 0; l <= (*pos - iter->func_pos); ) { - p = t_hash_next(m, p, &l); + p = t_hash_next(m, &l); if (!p) break; } - return p; + if (!p) + return NULL; + + return iter; } -static int t_hash_show(struct seq_file *m, void *v) +static int +t_hash_show(struct seq_file *m, struct ftrace_iterator *iter) { struct ftrace_func_probe *rec; - struct hlist_node *hnd = v; - rec = hlist_entry(hnd, struct ftrace_func_probe, node); + rec = iter->probe; + if (WARN_ON_ONCE(!rec)) + return -EIO; if (rec->ops->print) return rec->ops->print(m, rec->ip, rec->ops, rec->data); @@ -1461,7 +1475,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos) struct dyn_ftrace *rec = NULL; if (iter->flags & FTRACE_ITER_HASH) - return t_hash_next(m, v, pos); + return t_hash_next(m, pos); (*pos)++; @@ -1495,7 +1509,12 @@ t_next(struct seq_file *m, void *v, loff_t *pos) } } - return rec; + if (!rec) + return NULL; + + iter->func = rec; + + return iter; } static void *t_start(struct seq_file *m, loff_t *pos) @@ -1530,10 +1549,14 @@ static void *t_start(struct seq_file *m, loff_t *pos) break; } - if (!p && iter->flags & FTRACE_ITER_FILTER) - return t_hash_start(m, pos); + if (!p) { + if (iter->flags & FTRACE_ITER_FILTER) + return t_hash_start(m, pos); - return p; + return NULL; + } + + return iter; } static void t_stop(struct seq_file *m, void *p) @@ -1544,16 +1567,18 @@ static void t_stop(struct seq_file *m, void *p) static int t_show(struct seq_file *m, void *v) { struct ftrace_iterator *iter = m->private; - struct dyn_ftrace *rec = v; + struct dyn_ftrace *rec; if (iter->flags & FTRACE_ITER_HASH) - return t_hash_show(m, v); + return t_hash_show(m, iter); if (iter->flags & FTRACE_ITER_PRINTALL) { seq_printf(m, "#### all functions enabled ####\n"); return 0; } + rec = iter->func; + if (!rec) return 0; -- 1.7.1