This contains 3 changes:

- Removal of code I accidentally applied when doing a minor fix up
    to a patch, and then using "git commit -a --amend", which pulled
    in some other changes I was playing with.
 
  - Remove an used variable in trace_events_inject code
 
  - Fix to function graph tracer when it traces a ftrace direct function.
    It will now ignore tracing a function that has a ftrace direct
    tramploine attached. This is needed for eBPF to use the ftrace direct
    code.
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Merge tag 'trace-v5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Remove code I accidentally applied when doing a minor fix up to a
   patch, and then using "git commit -a --amend", which pulled in some
   other changes I was playing with.

 - Remove an used variable in trace_events_inject code

 - Fix function graph tracer when it traces a ftrace direct function.
   It will now ignore tracing a function that has a ftrace direct
   tramploine attached. This is needed for eBPF to use the ftrace direct
   code.

* tag 'trace-v5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix function_graph tracer interaction with BPF trampoline
  tracing: remove set but not used variable 'buffer'
  module: Remove accidental change of module_enable_x()
This commit is contained in:
Linus Torvalds 2019-12-11 12:22:38 -08:00
commit 6674fdb25a
6 changed files with 22 additions and 33 deletions

View File

@ -1042,20 +1042,6 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
if (unlikely(atomic_read(&current->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

View File

@ -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

View File

@ -3730,6 +3730,7 @@ static int complete_formation(struct module *mod, struct load_info *info)
module_enable_ro(mod, false);
module_enable_nx(mod);
module_enable_x(mod);
/* Mark state as coming so strong_try_module_get() ignores us,
* but kallsyms etc. can see us. */
@ -3752,11 +3753,6 @@ static int prepare_coming_module(struct module *mod)
if (err)
return err;
/* Make module executable after ftrace is enabled */
mutex_lock(&module_mutex);
module_enable_x(mod);
mutex_unlock(&module_mutex);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_COMING, mod);
return 0;

View File

@ -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;

View File

@ -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;
}

View File

@ -17,12 +17,10 @@ static int
trace_inject_entry(struct trace_event_file *file, void *rec, int len)
{
struct trace_event_buffer fbuffer;
struct ring_buffer *buffer;
int written = 0;
void *entry;
rcu_read_lock_sched();
buffer = file->tr->trace_buffer.buffer;
entry = trace_event_buffer_reserve(&fbuffer, file, len);
if (entry) {
memcpy(entry, rec, len);