Small fixes and minor cleanups for Tracing

- Make exported ftrace function not static
  - Fix NULL pointer dereference in reading probes as they are created
  - Fix NULL pointer dereference in k/uprobe clean up path
  - Various documentation fixes
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Merge tag 'trace-v5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Small fixes and minor cleanups for tracing:

   - Make exported ftrace function not static

   - Fix NULL pointer dereference in reading probes as they are created

   - Fix NULL pointer dereference in k/uprobe clean up path

   - Various documentation fixes"

* tag 'trace-v5.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Correct kdoc formats
  ftrace/x86: Remove mcount() declaration
  tracing/probe: Fix null pointer dereference
  tracing: Make exported ftrace_set_clr_event non-static
  ftrace: Check for successful allocation of hash
  ftrace: Check for empty hash and comment the race with registering probes
  ftrace: Fix NULL pointer dereference in t_probe_next()
This commit is contained in:
Linus Torvalds 2019-08-31 09:15:25 -07:00
commit 95381debd9
6 changed files with 35 additions and 15 deletions

View File

@ -16,7 +16,6 @@
#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
#ifndef __ASSEMBLY__
extern void mcount(void);
extern atomic_t modifying_ftrace_code;
extern void __fentry__(void);

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@ -548,6 +548,7 @@ extern int trace_event_get_offsets(struct trace_event_call *call);
#define is_signed_type(type) (((type)(-1)) < (type)1)
int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set);
int trace_set_clr_event(const char *system, const char *event, int set);
/*

View File

@ -3095,6 +3095,14 @@ t_probe_next(struct seq_file *m, loff_t *pos)
hnd = &iter->probe_entry->hlist;
hash = iter->probe->ops.func_hash->filter_hash;
/*
* A probe being registered may temporarily have an empty hash
* and it's at the end of the func_probes list.
*/
if (!hash || hash == EMPTY_HASH)
return NULL;
size = 1 << hash->size_bits;
retry:
@ -4320,12 +4328,21 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr,
mutex_unlock(&ftrace_lock);
/*
* Note, there's a small window here that the func_hash->filter_hash
* may be NULL or empty. Need to be carefule when reading the loop.
*/
mutex_lock(&probe->ops.func_hash->regex_lock);
orig_hash = &probe->ops.func_hash->filter_hash;
old_hash = *orig_hash;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
if (!hash) {
ret = -ENOMEM;
goto out;
}
ret = ftrace_match_records(hash, glob, strlen(glob));
/* Nothing found? */

View File

@ -1567,9 +1567,9 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
/**
* update_max_tr_single - only copy one trace over, and reset the rest
* @tr - tracer
* @tsk - task with the latency
* @cpu - the cpu of the buffer to copy.
* @tr: tracer
* @tsk: task with the latency
* @cpu: the cpu of the buffer to copy.
*
* Flip the trace of a single CPU buffer between the @tr and the max_tr.
*/
@ -1767,7 +1767,7 @@ static void __init apply_trace_boot_options(void);
/**
* register_tracer - register a tracer with the ftrace system.
* @type - the plugin for the tracer
* @type: the plugin for the tracer
*
* Register a new plugin tracer.
*/
@ -2230,9 +2230,9 @@ static bool tracing_record_taskinfo_skip(int flags)
/**
* tracing_record_taskinfo - record the task info of a task
*
* @task - task to record
* @flags - TRACE_RECORD_CMDLINE for recording comm
* - TRACE_RECORD_TGID for recording tgid
* @task: task to record
* @flags: TRACE_RECORD_CMDLINE for recording comm
* TRACE_RECORD_TGID for recording tgid
*/
void tracing_record_taskinfo(struct task_struct *task, int flags)
{
@ -2258,10 +2258,10 @@ void tracing_record_taskinfo(struct task_struct *task, int flags)
/**
* tracing_record_taskinfo_sched_switch - record task info for sched_switch
*
* @prev - previous task during sched_switch
* @next - next task during sched_switch
* @flags - TRACE_RECORD_CMDLINE for recording comm
* TRACE_RECORD_TGID for recording tgid
* @prev: previous task during sched_switch
* @next: next task during sched_switch
* @flags: TRACE_RECORD_CMDLINE for recording comm
* TRACE_RECORD_TGID for recording tgid
*/
void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
struct task_struct *next, int flags)
@ -3072,7 +3072,9 @@ static void trace_printk_start_stop_comm(int enabled)
/**
* trace_vbprintk - write binary msg to tracing buffer
*
* @ip: The address of the caller
* @fmt: The string format to write to the buffer
* @args: Arguments for @fmt
*/
int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
{

View File

@ -787,7 +787,7 @@ static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
return ret;
}
static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
{
char *event = NULL, *sub = NULL, *match;
int ret;

View File

@ -895,7 +895,8 @@ void trace_probe_cleanup(struct trace_probe *tp)
for (i = 0; i < tp->nr_args; i++)
traceprobe_free_probe_arg(&tp->args[i]);
kfree(call->class->system);
if (call->class)
kfree(call->class->system);
kfree(call->name);
kfree(call->print_fmt);
}