diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 060a361d9d11..024c3053dbba 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -1042,20 +1042,6 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; - /* - * If the return location is actually pointing directly to - * the start of a direct trampoline (if we trace the trampoline - * it will still be offset by MCOUNT_INSN_SIZE), then the - * return address is actually off by one word, and we - * need to adjust for that. - */ - if (ftrace_direct_func_count) { - if (ftrace_find_direct_func(self_addr + MCOUNT_INSN_SIZE)) { - self_addr = *parent; - parent++; - } - } - /* * Protect against fault, even if it shouldn't * happen. This tool is too much intrusive to diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 232806d5689d..987c2dc55bde 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -264,6 +264,7 @@ int ftrace_modify_direct_caller(struct ftrace_func_entry *entry, struct dyn_ftrace *rec, unsigned long old_addr, unsigned long new_addr); +unsigned long ftrace_find_rec_direct(unsigned long ip); #else # define ftrace_direct_func_count 0 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr) @@ -290,6 +291,10 @@ static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry, { return -ENODEV; } +static inline unsigned long ftrace_find_rec_direct(unsigned long ip) +{ + return 0; +} #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 67e0c462b059..a2659735db73 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -101,6 +101,15 @@ int function_graph_enter(unsigned long ret, unsigned long func, { struct ftrace_graph_ent trace; + /* + * Skip graph tracing if the return location is served by direct trampoline, + * since call sequence and return addresses is unpredicatable anymore. + * Ex: BPF trampoline may call original function and may skip frame + * depending on type of BPF programs attached. + */ + if (ftrace_direct_func_count && + ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE)) + return -EBUSY; trace.func = func; trace.depth = ++current->curr_ret_depth; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index caae523f4ef3..57477dc683db 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2364,7 +2364,7 @@ int ftrace_direct_func_count; * Search the direct_functions hash to see if the given instruction pointer * has a direct caller attached to it. */ -static unsigned long find_rec_direct(unsigned long ip) +unsigned long ftrace_find_rec_direct(unsigned long ip) { struct ftrace_func_entry *entry; @@ -2380,7 +2380,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip, { unsigned long addr; - addr = find_rec_direct(ip); + addr = ftrace_find_rec_direct(ip); if (!addr) return; @@ -2393,11 +2393,6 @@ struct ftrace_ops direct_ops = { | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_PERMANENT, }; -#else -static inline unsigned long find_rec_direct(unsigned long ip) -{ - return 0; -} #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** @@ -2417,7 +2412,7 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) if ((rec->flags & FTRACE_FL_DIRECT) && (ftrace_rec_count(rec) == 1)) { - addr = find_rec_direct(rec->ip); + addr = ftrace_find_rec_direct(rec->ip); if (addr) return addr; WARN_ON_ONCE(1); @@ -2458,7 +2453,7 @@ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) /* Direct calls take precedence over trampolines */ if (rec->flags & FTRACE_FL_DIRECT_EN) { - addr = find_rec_direct(rec->ip); + addr = ftrace_find_rec_direct(rec->ip); if (addr) return addr; WARN_ON_ONCE(1); @@ -3604,7 +3599,7 @@ static int t_show(struct seq_file *m, void *v) if (rec->flags & FTRACE_FL_DIRECT) { unsigned long direct; - direct = find_rec_direct(rec->ip); + direct = ftrace_find_rec_direct(rec->ip); if (direct) seq_printf(m, "\n\tdirect-->%pS", (void *)direct); } @@ -5008,7 +5003,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr) mutex_lock(&direct_mutex); /* See if there's a direct function at @ip already */ - if (find_rec_direct(ip)) + if (ftrace_find_rec_direct(ip)) goto out_unlock; ret = -ENODEV; @@ -5027,7 +5022,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr) if (ip != rec->ip) { ip = rec->ip; /* Need to check this ip for a direct. */ - if (find_rec_direct(ip)) + if (ftrace_find_rec_direct(ip)) goto out_unlock; }