From 39daa7b9e89512f234b7fb5d55812a78318251fc Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Nov 2015 15:12:38 -0500 Subject: [PATCH] ftrace: Show all tramps registered to a record on ftrace_bug() When an anomaly is detected in the function call modification code, ftrace_bug() is called to disable function tracing as well as give any information that may help debug the problem. Currently, only the first found trampoline that is attached to the failed record is reported. Instead, show all trampolines that are hooked to it. Also, not only show the ops pointer but also report the function it calls. While at it, add this info to the enabled_functions debug file too. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 46 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 37 insertions(+), 9 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 7870c03b4c4d..e371aed51fcf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1952,6 +1952,8 @@ static void print_ip_ins(const char *fmt, const unsigned char *p) static struct ftrace_ops * ftrace_find_tramp_ops_any(struct dyn_ftrace *rec); +static struct ftrace_ops * +ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops); enum ftrace_bug_type ftrace_bug_type; const void *ftrace_expected; @@ -2028,15 +2030,19 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec) rec->flags & FTRACE_FL_REGS ? " R" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); - if (ops) - pr_cont("\ttramp: %pS", - (void *)ops->trampoline); - else + if (ops) { + do { + pr_cont("\ttramp: %pS (%pS)", + (void *)ops->trampoline, + (void *)ops->func); + ops = ftrace_find_tramp_ops_next(rec, ops); + } while (ops); + } else pr_cont("\ttramp: ERROR!"); } ip = ftrace_get_addr_curr(rec); - pr_cont(" expected tramp: %lx\n", ip); + pr_cont("\n expected tramp: %lx\n", ip); } } @@ -2178,6 +2184,24 @@ ftrace_find_tramp_ops_any(struct dyn_ftrace *rec) return NULL; } +static struct ftrace_ops * +ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, + struct ftrace_ops *op) +{ + unsigned long ip = rec->ip; + + while_for_each_ftrace_op(op) { + + if (!op->trampoline) + continue; + + if (hash_contains_ip(ip, op->func_hash)) + return op; + } + + return NULL; +} + static struct ftrace_ops * ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) { @@ -3306,10 +3330,14 @@ static int t_show(struct seq_file *m, void *v) rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); - if (ops) - seq_printf(m, "\ttramp: %pS", - (void *)ops->trampoline); - else + if (ops) { + do { + seq_printf(m, "\ttramp: %pS (%pS)", + (void *)ops->trampoline, + (void *)ops->func); + ops = ftrace_find_tramp_ops_next(rec, ops); + } while (ops); + } else seq_puts(m, "\ttramp: ERROR!"); }