Merge branch 'for-next/stacktrace' into for-next/core (cb20311e) · Commits · jan.koester / Linux

arch/arm64/kernel/Makefile

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -14,6 +14,11 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE)
	CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong		CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong
	CFLAGS_syscall.o += -fno-stack-protector		CFLAGS_syscall.o += -fno-stack-protector

			# When KASAN is enabled, a stack trace is recorded for every alloc/free, which
			# can significantly impact performance. Avoid instrumenting the stack trace
			# collection code to minimize this impact.
			KASAN_SANITIZE_stacktrace.o := n

	# It's not safe to invoke KCOV when portions of the kernel environment aren't		# It's not safe to invoke KCOV when portions of the kernel environment aren't
	# available or are out-of-sync with HW state. Since `noinstr` doesn't always		# available or are out-of-sync with HW state. Since `noinstr` doesn't always
	# inhibit KCOV instrumentation, disable it for the entire compilation unit.		# inhibit KCOV instrumentation, disable it for the entire compilation unit.

arch/arm64/kernel/stacktrace.c

+75 −24

Original line number	Original line	Diff line number	Diff line
	@@ -38,6 +38,8 @@
	* @kr_cur: When KRETPROBES is selected, holds the kretprobe instance		* @kr_cur: When KRETPROBES is selected, holds the kretprobe instance
	* associated with the most recently encountered replacement lr		* associated with the most recently encountered replacement lr
	* value.		* value.
			*
			* @task: The task being unwound.
	*/		*/
	struct unwind_state {		struct unwind_state {
	unsigned long fp;		unsigned long fp;
	@@ -48,13 +50,13 @@ struct unwind_state {
	#ifdef CONFIG_KRETPROBES		#ifdef CONFIG_KRETPROBES
	struct llist_node *kr_cur;		struct llist_node *kr_cur;
	#endif		#endif
			struct task_struct *task;
	};		};

	static notrace void unwind_init(struct unwind_state *state, unsigned long fp,		static void unwind_init_common(struct unwind_state *state,
	unsigned long pc)		struct task_struct *task)
	{		{
	state->fp = fp;		state->task = task;
	state->pc = pc;
	#ifdef CONFIG_KRETPROBES		#ifdef CONFIG_KRETPROBES
	state->kr_cur = NULL;		state->kr_cur = NULL;
	#endif		#endif
	@@ -72,7 +74,57 @@ static notrace void unwind_init(struct unwind_state *state, unsigned long fp,
	state->prev_fp = 0;		state->prev_fp = 0;
	state->prev_type = STACK_TYPE_UNKNOWN;		state->prev_type = STACK_TYPE_UNKNOWN;
	}		}
	NOKPROBE_SYMBOL(unwind_init);
			/*
			* Start an unwind from a pt_regs.
			*
			* The unwind will begin at the PC within the regs.
			*
			* The regs must be on a stack currently owned by the calling task.
			*/
			static inline void unwind_init_from_regs(struct unwind_state *state,
			struct pt_regs *regs)
			{
			unwind_init_common(state, current);

			state->fp = regs->regs[29];
			state->pc = regs->pc;
			}

			/*
			* Start an unwind from a caller.
			*
			* The unwind will begin at the caller of whichever function this is inlined
			* into.
			*
			* The function which invokes this must be noinline.
			*/
			static __always_inline void unwind_init_from_caller(struct unwind_state *state)
			{
			unwind_init_common(state, current);

			state->fp = (unsigned long)__builtin_frame_address(1);
			state->pc = (unsigned long)__builtin_return_address(0);
			}

			/*
			* Start an unwind from a blocked task.
			*
			* The unwind will begin at the blocked tasks saved PC (i.e. the caller of
			* cpu_switch_to()).
			*
			* The caller should ensure the task is blocked in cpu_switch_to() for the
			* duration of the unwind, or the unwind will be bogus. It is never valid to
			* call this for the current task.
			*/
			static inline void unwind_init_from_task(struct unwind_state *state,
			struct task_struct *task)
			{
			unwind_init_common(state, task);

			state->fp = thread_saved_fp(task);
			state->pc = thread_saved_pc(task);
			}

	/*		/*
	* Unwind from one frame record (A) to the next frame record (B).		* Unwind from one frame record (A) to the next frame record (B).
	@@ -81,9 +133,9 @@ NOKPROBE_SYMBOL(unwind_init);
	* records (e.g. a cycle), determined based on the location and fp value of A		* records (e.g. a cycle), determined based on the location and fp value of A
	* and the location (but not the fp value) of B.		* and the location (but not the fp value) of B.
	*/		*/
	static int notrace unwind_next(struct task_struct *tsk,		static int notrace unwind_next(struct unwind_state *state)
	struct unwind_state *state)
	{		{
			struct task_struct *tsk = state->task;
	unsigned long fp = state->fp;		unsigned long fp = state->fp;
	struct stack_info info;		struct stack_info info;

	@@ -117,15 +169,15 @@ static int notrace unwind_next(struct task_struct *tsk,
	if (fp <= state->prev_fp)		if (fp <= state->prev_fp)
	return -EINVAL;		return -EINVAL;
	} else {		} else {
	set_bit(state->prev_type, state->stacks_done);		__set_bit(state->prev_type, state->stacks_done);
	}		}

	/*		/*
	* Record this frame record's values and location. The prev_fp and		* Record this frame record's values and location. The prev_fp and
	* prev_type are only meaningful to the next unwind_next() invocation.		* prev_type are only meaningful to the next unwind_next() invocation.
	*/		*/
	state->fp = READ_ONCE_NOCHECK((unsigned long )(fp));		state->fp = READ_ONCE((unsigned long )(fp));
	state->pc = READ_ONCE_NOCHECK((unsigned long )(fp + 8));		state->pc = READ_ONCE((unsigned long )(fp + 8));
	state->prev_fp = fp;		state->prev_fp = fp;
	state->prev_type = info.type;		state->prev_type = info.type;

	@@ -157,8 +209,7 @@ static int notrace unwind_next(struct task_struct *tsk,
	}		}
	NOKPROBE_SYMBOL(unwind_next);		NOKPROBE_SYMBOL(unwind_next);

	static void notrace unwind(struct task_struct *tsk,		static void notrace unwind(struct unwind_state *state,
	struct unwind_state *state,
	stack_trace_consume_fn consume_entry, void *cookie)		stack_trace_consume_fn consume_entry, void *cookie)
	{		{
	while (1) {		while (1) {
	@@ -166,7 +217,7 @@ static void notrace unwind(struct task_struct *tsk,

	if (!consume_entry(cookie, state->pc))		if (!consume_entry(cookie, state->pc))
	break;		break;
	ret = unwind_next(tsk, state);		ret = unwind_next(state);
	if (ret < 0)		if (ret < 0)
	break;		break;
	}		}
	@@ -212,15 +263,15 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
	{		{
	struct unwind_state state;		struct unwind_state state;

	if (regs)		if (regs) {
	unwind_init(&state, regs->regs[29], regs->pc);		if (task != current)
	else if (task == current)		return;
	unwind_init(&state,		unwind_init_from_regs(&state, regs);
	(unsigned long)__builtin_frame_address(1),		} else if (task == current) {
	(unsigned long)__builtin_return_address(0));		unwind_init_from_caller(&state);
	else		} else {
	unwind_init(&state, thread_saved_fp(task),		unwind_init_from_task(&state, task);
	thread_saved_pc(task));		}

	unwind(task, &state, consume_entry, cookie);		unwind(&state, consume_entry, cookie);
	}		}