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8a524f803a
Hans managed to trigger a WARN very early in the boot which killed his
(Virtual) box.
The reason is that the recent rework of WARN() to use UD0 forgot to add the
fixup_bug() call to early_fixup_exception(). As a result the kernel does
not handle the WARN_ON injected UD0 exception and panics.
Add the missing fixup call, so early UD's injected by WARN() get handled.
Fixes: 9a93848fe7 ("x86/debug: Implement __WARN() using UD0")
Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frank Mehnert <frank.mehnert@oracle.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Michael Thayer <michael.thayer@oracle.com>
Link: http://lkml.kernel.org/r/20170612180108.w4vgu2ckucmllf3a@hirez.programming.kicks-ass.net
37 lines
1.2 KiB
C
37 lines
1.2 KiB
C
#ifndef _ASM_X86_EXTABLE_H
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#define _ASM_X86_EXTABLE_H
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/*
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* The exception table consists of triples of addresses relative to the
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* exception table entry itself. The first address is of an instruction
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* that is allowed to fault, the second is the target at which the program
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* should continue. The third is a handler function to deal with the fault
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* caused by the instruction in the first field.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry {
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int insn, fixup, handler;
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};
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struct pt_regs;
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#define ARCH_HAS_RELATIVE_EXTABLE
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#define swap_ex_entry_fixup(a, b, tmp, delta) \
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do { \
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(a)->fixup = (b)->fixup + (delta); \
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(b)->fixup = (tmp).fixup - (delta); \
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(a)->handler = (b)->handler + (delta); \
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(b)->handler = (tmp).handler - (delta); \
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} while (0)
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extern int fixup_exception(struct pt_regs *regs, int trapnr);
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extern int fixup_bug(struct pt_regs *regs, int trapnr);
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extern bool ex_has_fault_handler(unsigned long ip);
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extern void early_fixup_exception(struct pt_regs *regs, int trapnr);
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#endif
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