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authorPeter Zijlstra <peterz@infradead.org>2017-06-12 13:52:46 +0200
committerThomas Gleixner <tglx@linutronix.de>2017-06-12 21:17:48 +0200
commit8a524f803a3e0290cdba6d373361b2cef9752934 (patch)
tree6de661f3898c330e2f7c418dae74e7363951d544
parent32c1431eea4881a6b17bd7c639315010aeefa452 (diff)
x86/debug: Handle early WARN_ONs proper
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: 9a93848fe787 ("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
-rw-r--r--arch/x86/include/asm/extable.h1
-rw-r--r--arch/x86/kernel/traps.c2
-rw-r--r--arch/x86/mm/extable.c3
3 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/include/asm/extable.h b/arch/x86/include/asm/extable.h
index b8ad261d11dc..c66d19e3c23e 100644
--- a/arch/x86/include/asm/extable.h
+++ b/arch/x86/include/asm/extable.h
@@ -29,6 +29,7 @@ struct pt_regs;
} while (0)
extern int fixup_exception(struct pt_regs *regs, int trapnr);
+extern int fixup_bug(struct pt_regs *regs, int trapnr);
extern bool ex_has_fault_handler(unsigned long ip);
extern void early_fixup_exception(struct pt_regs *regs, int trapnr);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 3995d3a777d4..bf54309b85da 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -182,7 +182,7 @@ int is_valid_bugaddr(unsigned long addr)
return ud == INSN_UD0 || ud == INSN_UD2;
}
-static int fixup_bug(struct pt_regs *regs, int trapnr)
+int fixup_bug(struct pt_regs *regs, int trapnr)
{
if (trapnr != X86_TRAP_UD)
return 0;
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 35ea061010a1..0ea8afcb929c 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -162,6 +162,9 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
if (fixup_exception(regs, trapnr))
return;
+ if (fixup_bug(regs, trapnr))
+ return;
+
fail:
early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n",
(unsigned)trapnr, (unsigned long)regs->cs, regs->ip,