mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 06:45:09 +07:00
84936118bd
There are a handful of callers to save_stack_trace_tsk() and show_stack() which try to unwind the stack of a task other than current. In such cases, it's remotely possible that the task is running on one CPU while the unwinder is reading its stack from another CPU, causing the unwinder to see stack corruption. These cases seem to be mostly harmless. The unwinder has checks which prevent it from following bad pointers beyond the bounds of the stack. So it's not really a bug as long as the caller understands that unwinding another task will not always succeed. In such cases, it's possible that the unwinder may read a KASAN-poisoned region of the stack. Account for that by using READ_ONCE_NOCHECK() when reading the stack of another task. Use READ_ONCE() when reading the stack of the current task, since KASAN warnings can still be useful for finding bugs in that case. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/4c575eb288ba9f73d498dfe0acde2f58674598f1.1483978430.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
116 lines
2.5 KiB
C
116 lines
2.5 KiB
C
/*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
|
|
*/
|
|
|
|
#ifndef _ASM_X86_STACKTRACE_H
|
|
#define _ASM_X86_STACKTRACE_H
|
|
|
|
#include <linux/uaccess.h>
|
|
#include <linux/ptrace.h>
|
|
#include <asm/switch_to.h>
|
|
|
|
enum stack_type {
|
|
STACK_TYPE_UNKNOWN,
|
|
STACK_TYPE_TASK,
|
|
STACK_TYPE_IRQ,
|
|
STACK_TYPE_SOFTIRQ,
|
|
STACK_TYPE_EXCEPTION,
|
|
STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
|
|
};
|
|
|
|
struct stack_info {
|
|
enum stack_type type;
|
|
unsigned long *begin, *end, *next_sp;
|
|
};
|
|
|
|
bool in_task_stack(unsigned long *stack, struct task_struct *task,
|
|
struct stack_info *info);
|
|
|
|
int get_stack_info(unsigned long *stack, struct task_struct *task,
|
|
struct stack_info *info, unsigned long *visit_mask);
|
|
|
|
const char *stack_type_name(enum stack_type type);
|
|
|
|
static inline bool on_stack(struct stack_info *info, void *addr, size_t len)
|
|
{
|
|
void *begin = info->begin;
|
|
void *end = info->end;
|
|
|
|
return (info->type != STACK_TYPE_UNKNOWN &&
|
|
addr >= begin && addr < end &&
|
|
addr + len > begin && addr + len <= end);
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
#define STACKSLOTS_PER_LINE 8
|
|
#else
|
|
#define STACKSLOTS_PER_LINE 4
|
|
#endif
|
|
|
|
#ifdef CONFIG_FRAME_POINTER
|
|
static inline unsigned long *
|
|
get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
|
|
{
|
|
struct inactive_task_frame *frame;
|
|
|
|
if (regs)
|
|
return (unsigned long *)regs->bp;
|
|
|
|
if (task == current)
|
|
return __builtin_frame_address(0);
|
|
|
|
frame = (struct inactive_task_frame *)task->thread.sp;
|
|
return (unsigned long *)READ_ONCE_NOCHECK(frame->bp);
|
|
}
|
|
#else
|
|
static inline unsigned long *
|
|
get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif /* CONFIG_FRAME_POINTER */
|
|
|
|
static inline unsigned long *
|
|
get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
|
|
{
|
|
if (regs)
|
|
return (unsigned long *)kernel_stack_pointer(regs);
|
|
|
|
if (task == current)
|
|
return __builtin_frame_address(0);
|
|
|
|
return (unsigned long *)task->thread.sp;
|
|
}
|
|
|
|
void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
|
|
unsigned long *stack, char *log_lvl);
|
|
|
|
extern unsigned int code_bytes;
|
|
|
|
/* The form of the top of the frame on the stack */
|
|
struct stack_frame {
|
|
struct stack_frame *next_frame;
|
|
unsigned long return_address;
|
|
};
|
|
|
|
struct stack_frame_ia32 {
|
|
u32 next_frame;
|
|
u32 return_address;
|
|
};
|
|
|
|
static inline unsigned long caller_frame_pointer(void)
|
|
{
|
|
struct stack_frame *frame;
|
|
|
|
frame = __builtin_frame_address(0);
|
|
|
|
#ifdef CONFIG_FRAME_POINTER
|
|
frame = frame->next_frame;
|
|
#endif
|
|
|
|
return (unsigned long)frame;
|
|
}
|
|
|
|
#endif /* _ASM_X86_STACKTRACE_H */
|