Tracing updates:

- Addition of multiprobes to kprobe and uprobe events
    Allows for more than one probe attached to the same location
 
  - Addition of adding immediates to probe parameters
 
  - Clean up of the recordmcount.c code. This brings us closer
    to merging recordmcount into objtool, and reuse code.
 
  - Other small clean ups
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Merge tag 'trace-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Addition of multiprobes to kprobe and uprobe events (allows for more
   than one probe attached to the same location)

 - Addition of adding immediates to probe parameters

 - Clean up of the recordmcount.c code. This brings us closer to merging
   recordmcount into objtool, and reuse code.

 - Other small clean ups

* tag 'trace-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
  selftests/ftrace: Update kprobe event error testcase
  tracing/probe: Reject exactly same probe event
  tracing/probe: Fix to allow user to enable events on unloaded modules
  selftests/ftrace: Select an existing function in kprobe_eventname test
  tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink()
  tracing: Make sure variable reference alias has correct var_ref_idx
  tracing: Be more clever when dumping hex in __print_hex()
  ftrace: Simplify ftrace hash lookup code in clear_func_from_hash()
  tracing: Add "gfp_t" support in synthetic_events
  tracing: Rename tracing_reset() to tracing_reset_cpu()
  tracing: Document the stack trace algorithm in the comments
  tracing/arm64: Have max stack tracer handle the case of return address after data
  recordmcount: Clarify what cleanup() does
  recordmcount: Remove redundant cleanup() calls
  recordmcount: Kernel style formatting
  recordmcount: Kernel style function signature formatting
  recordmcount: Rewrite error/success handling
  selftests/ftrace: Add syntax error test for multiprobe
  selftests/ftrace: Add syntax error test for immediates
  selftests/ftrace: Add a testcase for kprobe multiprobe event
  ...
This commit is contained in:
Linus Torvalds 2019-09-20 11:19:48 -07:00
commit 45979a956b
22 changed files with 1199 additions and 406 deletions

View file

@ -961,9 +961,16 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
#ifdef CONFIG_KPROBES_ON_FTRACE
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
.func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS,
};
static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
.func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
};
static int kprobe_ipmodify_enabled;
static int kprobe_ftrace_enabled;
/* Must ensure p->addr is really on ftrace */
@ -976,58 +983,75 @@ static int prepare_kprobe(struct kprobe *p)
}
/* Caller must lock kprobe_mutex */
static int arm_kprobe_ftrace(struct kprobe *p)
static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
int *cnt)
{
int ret = 0;
ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
(unsigned long)p->addr, 0, 0);
ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
if (ret) {
pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n",
p->addr, ret);
return ret;
}
if (kprobe_ftrace_enabled == 0) {
ret = register_ftrace_function(&kprobe_ftrace_ops);
if (*cnt == 0) {
ret = register_ftrace_function(ops);
if (ret) {
pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
goto err_ftrace;
}
}
kprobe_ftrace_enabled++;
(*cnt)++;
return ret;
err_ftrace:
/*
* Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
* non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
* empty filter_hash which would undesirably trace all functions.
* At this point, sinec ops is not registered, we should be sefe from
* registering empty filter.
*/
ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
return ret;
}
static int arm_kprobe_ftrace(struct kprobe *p)
{
bool ipmodify = (p->post_handler != NULL);
return __arm_kprobe_ftrace(p,
ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
}
/* Caller must lock kprobe_mutex */
static int disarm_kprobe_ftrace(struct kprobe *p)
static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
int *cnt)
{
int ret = 0;
if (kprobe_ftrace_enabled == 1) {
ret = unregister_ftrace_function(&kprobe_ftrace_ops);
if (*cnt == 1) {
ret = unregister_ftrace_function(ops);
if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
return ret;
}
kprobe_ftrace_enabled--;
(*cnt)--;
ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
(unsigned long)p->addr, 1, 0);
ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n",
p->addr, ret);
return ret;
}
static int disarm_kprobe_ftrace(struct kprobe *p)
{
bool ipmodify = (p->post_handler != NULL);
return __disarm_kprobe_ftrace(p,
ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
}
#else /* !CONFIG_KPROBES_ON_FTRACE */
#define prepare_kprobe(p) arch_prepare_kprobe(p)
#define arm_kprobe_ftrace(p) (-ENODEV)