Commit 45979a95 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
  ...
parents 3207598a b78b94b8

Documentation/trace/kprobetrace.rst

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ Synopsis of kprobe_events 
  $retval	: Fetch return value.(\*2)

  $comm		: Fetch current task comm.

  +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*3)(\*4)

  \IMM		: Store an immediate value to the argument.

  NAME=FETCHARG : Set NAME as the argument name of FETCHARG.

  FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types

		  (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types

Documentation/trace/uprobetracer.rst

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ Synopsis of uprobe_tracer 
   $retval	: Fetch return value.(\*1)

   $comm	: Fetch current task comm.

   +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*2)(\*3)

   \IMM		: Store an immediate value to the argument.

   NAME=FETCHARG     : Set NAME as the argument name of FETCHARG.

   FETCHARG:TYPE     : Set TYPE as the type of FETCHARG. Currently, basic types

		       (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types

arch/arm64/include/asm/ftrace.h

+13 −0
Original line number Diff line number Diff line
@@ -14,6 +14,19 @@ 
#define MCOUNT_ADDR		((unsigned long)_mcount)

#define MCOUNT_INSN_SIZE	AARCH64_INSN_SIZE



/*

 * Currently, gcc tends to save the link register after the local variables

 * on the stack. This causes the max stack tracer to report the function

 * frame sizes for the wrong functions. By defining

 * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect

 * to find the return address on the stack after the local variables have

 * been set up.

 *

 * Note, this may change in the future, and we will need to deal with that

 * if it were to happen.

 */

#define ARCH_FTRACE_SHIFT_STACK_TRACER 1



#ifndef __ASSEMBLY__

#include <linux/compat.h>

kernel/kprobes.c

+40 −16
Original line number Diff line number Diff line
@@ -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)

kernel/trace/ftrace.c

+1 −5
Original line number Diff line number Diff line
@@ -6036,11 +6036,7 @@ clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash) 
{

	struct ftrace_func_entry *entry;



	if (ftrace_hash_empty(hash))

		return;



	entry = __ftrace_lookup_ip(hash, func->ip);



	entry = ftrace_lookup_ip(hash, func->ip);

	/*

	 * Do not allow this rec to match again.

	 * Yeah, it may waste some memory, but will be removed

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