Merge tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - kprobes: Restructured stack unwinder to show properly on x86 when a
   stack dump happens from a kretprobe callback.

 - Fix to bootconfig parsing

 - Have tracefs allow owner and group permissions by default (only
   denying others). There's been pressure to allow non root to tracefs
   in a controlled fashion, and using groups is probably the safest.

 - Bootconfig memory managament updates.

 - Bootconfig clean up to have the tools directory be less dependent on
   changes in the kernel tree.

 - Allow perf to be traced by function tracer.

 - Rewrite of function graph tracer to be a callback from the function
   tracer instead of having its own trampoline (this change will happen
   on an arch by arch basis, and currently only x86_64 implements it).

 - Allow multiple direct trampolines (bpf hooks to functions) be batched
   together in one synchronization.

 - Allow histogram triggers to add variables that can perform
   calculations against the event's fields.

 - Use the linker to determine architecture callbacks from the ftrace
   trampoline to allow for proper parameter prototypes and prevent
   warnings from the compiler.

 - Extend histogram triggers to key off of variables.

 - Have trace recursion use bit magic to determine preempt context over
   if branches.

 - Have trace recursion disable preemption as all use cases do anyway.

 - Added testing for verification of tracing utilities.

 - Various small clean ups and fixes.

* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
  tracing/histogram: Fix semicolon.cocci warnings
  tracing/histogram: Fix documentation inline emphasis warning
  tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
  tracing: Show size of requested perf buffer
  bootconfig: Initialize ret in xbc_parse_tree()
  ftrace: do CPU checking after preemption disabled
  ftrace: disable preemption when recursion locked
  tracing/histogram: Document expression arithmetic and constants
  tracing/histogram: Optimize division by a power of 2
  tracing/histogram: Covert expr to const if both operands are constants
  tracing/histogram: Simplify handling of .sym-offset in expressions
  tracing: Fix operator precedence for hist triggers expression
  tracing: Add division and multiplication support for hist triggers
  tracing: Add support for creating hist trigger variables from literal
  selftests/ftrace: Stop tracing while reading the trace file by default
  MAINTAINERS: Update KPROBES and TRACING entries
  test_kprobes: Move it from kernel/ to lib/
  docs, kprobes: Remove invalid URL and add new reference
  samples/kretprobes: Fix return value if register_kretprobe() failed
  lib/bootconfig: Fix the xbc_get_info kerneldoc
  ...

3 files changed, 10 insertions, 13 deletions

diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 1d94ffdf347b..5165bf344f95 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -262,11 +262,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	return 0;
 }
 
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
-
 void arch_ftrace_update_code(int command)
 {
 	if (ftrace_shared_hotpatch_trampoline(NULL))
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 52d056a5f89f..c505c0ee5f47 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -7,6 +7,8 @@
  * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
  */
 
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/moduleloader.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
@@ -240,7 +242,7 @@ void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
+	regs->gprs[14] = (unsigned long) &__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 
@@ -259,7 +261,7 @@ static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p)
 		 * is a BUG. The code path resides in the .kprobes.text
 		 * section and is executed with interrupts disabled.
 		 */
-		pr_err("Invalid kprobe detected.\n");
+		pr_err("Failed to recover from reentered kprobes.\n");
 		dump_kprobe(p);
 		BUG();
 	}
@@ -332,8 +334,8 @@ NOKPROBE_SYMBOL(kprobe_handler);
  */
 static void __used kretprobe_trampoline_holder(void)
 {
-	asm volatile(".global kretprobe_trampoline\n"
-		     "kretprobe_trampoline: bcr 0,0\n");
+	asm volatile(".global __kretprobe_trampoline\n"
+		     "__kretprobe_trampoline: bcr 0,0\n");
 }
 
 /*
@@ -341,7 +343,7 @@ static void __used kretprobe_trampoline_holder(void)
  */
 static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-	regs->psw.addr = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+	regs->psw.addr = __kretprobe_trampoline_handler(regs, NULL);
 	/*
 	 * By returning a non-zero value, we are telling
 	 * kprobe_handler() that we don't want the post_handler
@@ -507,7 +509,7 @@ int kprobe_exceptions_notify(struct notifier_block *self,
 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
 
 static struct kprobe trampoline = {
-	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *) &__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 
@@ -518,6 +520,6 @@ int __init arch_init_kprobes(void)
 
 int arch_trampoline_kprobe(struct kprobe *p)
 {
-	return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline;
+	return p->addr == (kprobe_opcode_t *) &__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_trampoline_kprobe);
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 101477b3e263..b7bb1981e9ee 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -46,7 +46,7 @@ int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
 		 * Mark stacktraces with kretprobed functions on them
 		 * as unreliable.
 		 */
-		if (state.ip == (unsigned long)kretprobe_trampoline)
+		if (state.ip == (unsigned long)__kretprobe_trampoline)
 			return -EINVAL;
 #endif