0ee1dd9f5e
For mostly historical reasons, the x86 oops dump shows the raw stack values: ... [registers] Stack: ffff880079af7350 ffff880079905400 0000000000000000 ffffc900008f3ae0 ffffffffa0196610 0000000000000001 00010000ffffffff 0000000087654321 0000000000000002 0000000000000000 0000000000000000 0000000000000000 Call Trace: ... This seems to be an artifact from long ago, and probably isn't needed anymore. It generally just adds noise to the dump, and it can be actively harmful because it leaks kernel addresses. Linus says: "The stack dump actually goes back to forever, and it used to be useful back in 1992 or so. But it used to be useful mainly because stacks were simpler and we didn't have very good call traces anyway. I definitely remember having used them - I just do not remember having used them in the last ten+ years. Of course, it's still true that if you can trigger an oops, you've likely already lost the security game, but since the stack dump is so useless, let's aim to just remove it and make games like the above harder." This also removes the related 'kstack=' cmdline option and the 'kstack_depth_to_print' sysctl. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e83bd50df52d8fe88e94d2566426ae40d813bf8f.1477405374.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
114 lines
2.5 KiB
C
114 lines
2.5 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#ifndef _ASM_X86_STACKTRACE_H
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#define _ASM_X86_STACKTRACE_H
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#include <linux/uaccess.h>
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#include <linux/ptrace.h>
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#include <asm/switch_to.h>
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enum stack_type {
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STACK_TYPE_UNKNOWN,
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STACK_TYPE_TASK,
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STACK_TYPE_IRQ,
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STACK_TYPE_SOFTIRQ,
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STACK_TYPE_EXCEPTION,
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STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
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};
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struct stack_info {
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enum stack_type type;
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unsigned long *begin, *end, *next_sp;
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};
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bool in_task_stack(unsigned long *stack, struct task_struct *task,
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struct stack_info *info);
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int get_stack_info(unsigned long *stack, struct task_struct *task,
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struct stack_info *info, unsigned long *visit_mask);
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void stack_type_str(enum stack_type type, const char **begin,
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const char **end);
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static inline bool on_stack(struct stack_info *info, void *addr, size_t len)
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{
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void *begin = info->begin;
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void *end = info->end;
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return (info->type != STACK_TYPE_UNKNOWN &&
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addr >= begin && addr < end &&
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addr + len > begin && addr + len <= end);
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}
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#ifdef CONFIG_X86_32
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#define STACKSLOTS_PER_LINE 8
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#else
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#define STACKSLOTS_PER_LINE 4
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#endif
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#ifdef CONFIG_FRAME_POINTER
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static inline unsigned long *
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get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
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{
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if (regs)
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return (unsigned long *)regs->bp;
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if (task == current)
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return __builtin_frame_address(0);
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return (unsigned long *)((struct inactive_task_frame *)task->thread.sp)->bp;
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}
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#else
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static inline unsigned long *
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get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
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{
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return NULL;
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}
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#endif /* CONFIG_FRAME_POINTER */
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static inline unsigned long *
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get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
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{
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if (regs)
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return (unsigned long *)kernel_stack_pointer(regs);
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if (task == current)
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return __builtin_frame_address(0);
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return (unsigned long *)task->thread.sp;
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}
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void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *stack, char *log_lvl);
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extern unsigned int code_bytes;
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/* The form of the top of the frame on the stack */
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struct stack_frame {
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struct stack_frame *next_frame;
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unsigned long return_address;
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};
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struct stack_frame_ia32 {
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u32 next_frame;
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u32 return_address;
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};
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static inline unsigned long caller_frame_pointer(void)
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{
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struct stack_frame *frame;
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frame = __builtin_frame_address(0);
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#ifdef CONFIG_FRAME_POINTER
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frame = frame->next_frame;
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#endif
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return (unsigned long)frame;
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}
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#endif /* _ASM_X86_STACKTRACE_H */
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