Commit f44d5c48 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull more tracing fixes from Steven Rostedt:
 "Various tracing fixes:

   - Fix a crash when having function tracing and function stack tracing
     on the command line.

     The ftrace trampolines are created as executable and read only. But
     the stack tracer tries to modify them with text_poke() which
     expects all kernel text to still be writable at boot. Keep the
     trampolines writable at boot, and convert them to read-only with
     the rest of the kernel.

   - A selftest was triggering in the ring buffer iterator code, that is
     no longer valid with the update of keeping the ring buffer writable
     while a iterator is reading.

     Just bail after three failed attempts to get an event and remove
     the warning and disabling of the ring buffer.

   - While modifying the ring buffer code, decided to remove all the
     unnecessary BUG() calls"

* tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ring-buffer: Remove all BUG() calls
  ring-buffer: Don't deactivate the ring buffer on failed iterator reads
  x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up
parents f492de9d da4d401a

arch/x86/include/asm/ftrace.h

+6 −0
Original line number Diff line number Diff line
@@ -56,6 +56,12 @@ struct dyn_arch_ftrace { 


#ifndef __ASSEMBLY__



#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)

extern void set_ftrace_ops_ro(void);

#else

static inline void set_ftrace_ops_ro(void) { }

#endif



#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME

static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)

{

arch/x86/kernel/ftrace.c

+28 −1
Original line number Diff line number Diff line
@@ -407,6 +407,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) 


	set_vm_flush_reset_perms(trampoline);



	if (likely(system_state != SYSTEM_BOOTING))

		set_memory_ro((unsigned long)trampoline, npages);

	set_memory_x((unsigned long)trampoline, npages);

	return (unsigned long)trampoline;
@@ -415,6 +416,32 @@ fail: 
	return 0;

}



void set_ftrace_ops_ro(void)

{

	struct ftrace_ops *ops;

	unsigned long start_offset;

	unsigned long end_offset;

	unsigned long npages;

	unsigned long size;



	do_for_each_ftrace_op(ops, ftrace_ops_list) {

		if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))

			continue;



		if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {

			start_offset = (unsigned long)ftrace_regs_caller;

			end_offset = (unsigned long)ftrace_regs_caller_end;

		} else {

			start_offset = (unsigned long)ftrace_caller;

			end_offset = (unsigned long)ftrace_epilogue;

		}

		size = end_offset - start_offset;

		size = size + RET_SIZE + sizeof(void *);

		npages = DIV_ROUND_UP(size, PAGE_SIZE);

		set_memory_ro((unsigned long)ops->trampoline, npages);

	} while_for_each_ftrace_op(ops);

}



static unsigned long calc_trampoline_call_offset(bool save_regs)

{

	unsigned long start_offset;

arch/x86/mm/init_64.c

+3 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ 
#include <asm/init.h>

#include <asm/uv/uv.h>

#include <asm/setup.h>

#include <asm/ftrace.h>



#include "mm_internal.h"
@@ -1291,6 +1292,8 @@ void mark_rodata_ro(void) 
	all_end = roundup((unsigned long)_brk_end, PMD_SIZE);

	set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT);



	set_ftrace_ops_ro();



#ifdef CONFIG_CPA_DEBUG

	printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, end);

	set_memory_rw(start, (end-start) >> PAGE_SHIFT);

include/linux/ftrace.h

+23 −0
Original line number Diff line number Diff line
@@ -210,6 +210,29 @@ struct ftrace_ops { 
#endif

};



extern struct ftrace_ops __rcu *ftrace_ops_list;

extern struct ftrace_ops ftrace_list_end;



/*

 * Traverse the ftrace_global_list, invoking all entries.  The reason that we

 * can use rcu_dereference_raw_check() is that elements removed from this list

 * are simply leaked, so there is no need to interact with a grace-period

 * mechanism.  The rcu_dereference_raw_check() calls are needed to handle

 * concurrent insertions into the ftrace_global_list.

 *

 * Silly Alpha and silly pointer-speculation compiler optimizations!

 */

#define do_for_each_ftrace_op(op, list)			\

	op = rcu_dereference_raw_check(list);			\

	do



/*

 * Optimized for just a single item in the list (as that is the normal case).

 */

#define while_for_each_ftrace_op(op)				\

	while (likely(op = rcu_dereference_raw_check((op)->next)) &&	\

	       unlikely((op) != &ftrace_list_end))



/*

 * Type of the current tracing.

 */

kernel/trace/ftrace_internal.h

+0 −22
Original line number Diff line number Diff line
@@ -4,28 +4,6 @@ 


#ifdef CONFIG_FUNCTION_TRACER



/*

 * Traverse the ftrace_global_list, invoking all entries.  The reason that we

 * can use rcu_dereference_raw_check() is that elements removed from this list

 * are simply leaked, so there is no need to interact with a grace-period

 * mechanism.  The rcu_dereference_raw_check() calls are needed to handle

 * concurrent insertions into the ftrace_global_list.

 *

 * Silly Alpha and silly pointer-speculation compiler optimizations!

 */

#define do_for_each_ftrace_op(op, list)			\

	op = rcu_dereference_raw_check(list);			\

	do



/*

 * Optimized for just a single item in the list (as that is the normal case).

 */

#define while_for_each_ftrace_op(op)				\

	while (likely(op = rcu_dereference_raw_check((op)->next)) &&	\

	       unlikely((op) != &ftrace_list_end))



extern struct ftrace_ops __rcu *ftrace_ops_list;

extern struct ftrace_ops ftrace_list_end;

extern struct mutex ftrace_lock;

extern struct ftrace_ops global_ops;

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