From 30f7d1cac2aab8fec560a388ad31ca5e5d04a822 Mon Sep 17 00:00:00 2001 From: Zheng Yejian Date: Tue, 11 Oct 2022 12:03:52 +0000 Subject: ftrace: Fix char print issue in print_ip_ins() When ftrace bug happened, following log shows every hex data in problematic ip address: actual: ffffffe8:6b:ffffffd9:01:21 But so many 'f's seem a little confusing, and that is because format '%x' being used to print signed chars in array 'ins'. As suggested by Joe, change to use format "%*phC" to print array 'ins'. After this patch, the log is like: actual: e8:6b:d9:01:21 Link: https://lkml.kernel.org/r/20221011120352.1878494-1-zhengyejian1@huawei.com Fixes: 6c14133d2d3f ("ftrace: Do not blindly read the ip address in ftrace_bug()") Suggested-by: Joe Perches Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'kernel/trace') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 83362a155791..75c16215d065 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2028,7 +2028,6 @@ static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, static void print_ip_ins(const char *fmt, const unsigned char *p) { char ins[MCOUNT_INSN_SIZE]; - int i; if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) { printk(KERN_CONT "%s[FAULT] %px\n", fmt, p); @@ -2036,9 +2035,7 @@ static void print_ip_ins(const char *fmt, const unsigned char *p) } printk(KERN_CONT "%s", fmt); - - for (i = 0; i < MCOUNT_INSN_SIZE; i++) - printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]); + pr_cont("%*phC", MCOUNT_INSN_SIZE, ins); } enum ftrace_bug_type ftrace_bug_type; -- cgit v1.2.3