Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d1526e2c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Remove stack unwinder for now 



It has caused more problems than it ever really solved, and is
apparently not getting cleaned up and fixed.  We can put it back when
it's stable and isn't likely to make warning or bug events worse.

In the meantime, enable frame pointers for more readable stack traces.

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d1998ef3

Makefile

+0 −5
Original line number Diff line number Diff line
@@ -496,11 +496,6 @@ else 
CFLAGS		+= -fomit-frame-pointer

endif



ifdef CONFIG_UNWIND_INFO

CFLAGS		+= -fasynchronous-unwind-tables

LDFLAGS_vmlinux	+= --eh-frame-hdr

endif



ifdef CONFIG_DEBUG_INFO

CFLAGS		+= -g

endif

arch/i386/defconfig

+0 −2
Original line number Diff line number Diff line
@@ -1493,8 +1493,6 @@ CONFIG_DEBUG_BUGVERBOSE=y 
# CONFIG_DEBUG_VM is not set

# CONFIG_DEBUG_LIST is not set

# CONFIG_FRAME_POINTER is not set

CONFIG_UNWIND_INFO=y

CONFIG_STACK_UNWIND=y

# CONFIG_FORCED_INLINING is not set

# CONFIG_HEADERS_CHECK is not set

# CONFIG_RCU_TORTURE_TEST is not set

arch/i386/kernel/entry.S

+0 −32
Original line number Diff line number Diff line
@@ -979,38 +979,6 @@ ENTRY(spurious_interrupt_bug) 
	jmp error_code

	CFI_ENDPROC



#ifdef CONFIG_STACK_UNWIND

ENTRY(arch_unwind_init_running)

	CFI_STARTPROC

	movl	4(%esp), %edx

	movl	(%esp), %ecx

	leal	4(%esp), %eax

	movl	%ebx, PT_EBX(%edx)

	xorl	%ebx, %ebx

	movl	%ebx, PT_ECX(%edx)

	movl	%ebx, PT_EDX(%edx)

	movl	%esi, PT_ESI(%edx)

	movl	%edi, PT_EDI(%edx)

	movl	%ebp, PT_EBP(%edx)

	movl	%ebx, PT_EAX(%edx)

	movl	$__USER_DS, PT_DS(%edx)

	movl	$__USER_DS, PT_ES(%edx)

	movl	$0, PT_GS(%edx)

	movl	%ebx, PT_ORIG_EAX(%edx)

	movl	%ecx, PT_EIP(%edx)

	movl	12(%esp), %ecx

	movl	$__KERNEL_CS, PT_CS(%edx)

	movl	%ebx, PT_EFLAGS(%edx)

	movl	%eax, PT_OLDESP(%edx)

	movl	8(%esp), %eax

	movl	%ecx, 8(%esp)

	movl	PT_EBX(%edx), %ebx

	movl	$__KERNEL_DS, PT_OLDSS(%edx)

	jmpl	*%eax

	CFI_ENDPROC

ENDPROC(arch_unwind_init_running)

#endif



ENTRY(kernel_thread_helper)

	pushl $0		# fake return address for unwinder

	CFI_STARTPROC

arch/i386/kernel/traps.c

+0 −83
Original line number Diff line number Diff line
@@ -94,11 +94,6 @@ asmlinkage void spurious_interrupt_bug(void); 
asmlinkage void machine_check(void);



int kstack_depth_to_print = 24;

#ifdef CONFIG_STACK_UNWIND

static int call_trace = 1;

#else

#define call_trace (-1)

#endif

ATOMIC_NOTIFIER_HEAD(i386die_chain);



int register_die_notifier(struct notifier_block *nb)
@@ -152,33 +147,6 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo, 
	return ebp;

}



struct ops_and_data {

	struct stacktrace_ops *ops;

	void *data;

};



static asmlinkage int

dump_trace_unwind(struct unwind_frame_info *info, void *data)

{

	struct ops_and_data *oad = (struct ops_and_data *)data;

	int n = 0;

	unsigned long sp = UNW_SP(info);



	if (arch_unw_user_mode(info))

		return -1;

	while (unwind(info) == 0 && UNW_PC(info)) {

		n++;

		oad->ops->address(oad->data, UNW_PC(info));

		if (arch_unw_user_mode(info))

			break;

		if ((sp & ~(PAGE_SIZE - 1)) == (UNW_SP(info) & ~(PAGE_SIZE - 1))

		    && sp > UNW_SP(info))

			break;

		sp = UNW_SP(info);

	}

	return n;

}



#define MSG(msg) ops->warning(data, msg)



void dump_trace(struct task_struct *task, struct pt_regs *regs,
@@ -190,41 +158,6 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, 
	if (!task)

		task = current;



	if (call_trace >= 0) {

		int unw_ret = 0;

		struct unwind_frame_info info;

		struct ops_and_data oad = { .ops = ops, .data = data };



		if (regs) {

			if (unwind_init_frame_info(&info, task, regs) == 0)

				unw_ret = dump_trace_unwind(&info, &oad);

		} else if (task == current)

			unw_ret = unwind_init_running(&info, dump_trace_unwind,

						      &oad);

		else {

			if (unwind_init_blocked(&info, task) == 0)

				unw_ret = dump_trace_unwind(&info, &oad);

		}

		if (unw_ret > 0) {

			if (call_trace == 1 && !arch_unw_user_mode(&info)) {

				ops->warning_symbol(data,

					     "DWARF2 unwinder stuck at %s",

					     UNW_PC(&info));

				if (UNW_SP(&info) >= PAGE_OFFSET) {

					MSG("Leftover inexact backtrace:");

					stack = (void *)UNW_SP(&info);

					if (!stack)

						return;

					ebp = UNW_FP(&info);

				} else

					MSG("Full inexact backtrace again:");

			} else if (call_trace >= 1)

				return;

			else

				MSG("Full inexact backtrace again:");

		} else

			MSG("Inexact backtrace:");

	}

	if (!stack) {

		unsigned long dummy;

		stack = &dummy;
@@ -1258,19 +1191,3 @@ static int __init kstack_setup(char *s) 
	return 1;

}

__setup("kstack=", kstack_setup);
 


#ifdef CONFIG_STACK_UNWIND

static int __init call_trace_setup(char *s)

{

	if (strcmp(s, "old") == 0)

		call_trace = -1;

	else if (strcmp(s, "both") == 0)

		call_trace = 0;

	else if (strcmp(s, "newfallback") == 0)

		call_trace = 1;

	else if (strcmp(s, "new") == 2)

		call_trace = 2;

	return 1;

}

__setup("call_trace=", call_trace_setup);

#endif

arch/x86_64/Makefile

+0 −2
Original line number Diff line number Diff line
@@ -45,9 +45,7 @@ cflags-kernel-$(CONFIG_REORDER) += -ffunction-sections 
# actually it makes the kernel smaller too.

cflags-y += -fno-reorder-blocks

cflags-y += -Wno-sign-compare

ifneq ($(CONFIG_UNWIND_INFO),y)

cflags-y += -fno-asynchronous-unwind-tables

endif

ifneq ($(CONFIG_DEBUG_INFO),y)

# -fweb shrinks the kernel a bit, but the difference is very small

# it also messes up debugging, so don't use it for now.