Messages in this thread | | | From | Zheng Yejian <> | Subject | Re: [PATCH] ftrace: Fix char print issue in print_ip_ins() | Date | Tue, 11 Oct 2022 11:22:32 +0000 |
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On Mon, 10 Oct 2022 19:35:38 -0700, Joe Perches <joe@perches.com> wrote: > On Mon, 2022-10-10 at 19:15 +0000, Zheng Yejian wrote: > > When ftrace bug happened, following log shows every byte data in > > problem ip address: > > actual: ffffffe8:6b:ffffffd9:01:21 > > > > However that seems a little confusing, and it is because format > > '%x' being used to print signed chars in print_ip_ins(). > > > > After this patch, the log is like: > > actual: e8:6b:d9:01:21 > > > > Fixes: 6c14133d2d3f ("ftrace: Do not blindly read the ip address in ftrace_bug()") > > Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> > > --- > > kernel/trace/ftrace.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > [] > > @@ -2015,7 +2015,7 @@ 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]; > > + unsigned char ins[MCOUNT_INSN_SIZE]; > > int i; > > > > if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) { > > Perhaps nicer would be to change the for loop below this from > > for (i = 0; i < MCOUNT_INSN_SIZE; i++) > printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]); > > to > > pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
It works, thanks for your suggestion. I'll send a new version patch.
-- Zheng Yejian
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