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| author | Peter Zijlstra <peterz@infradead.org> | 2017-06-12 13:52:46 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-06-12 21:17:48 +0200 |
| commit | 8a524f803a3e0290cdba6d373361b2cef9752934 (patch) | |
| tree | 6de661f3898c330e2f7c418dae74e7363951d544 /arch | |
| parent | Linux 4.12-rc5 (diff) | |
| download | linux-8a524f803a3e0290cdba6d373361b2cef9752934.tar.xz linux-8a524f803a3e0290cdba6d373361b2cef9752934.zip | |
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
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/extable.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 2 | ||||
| -rw-r--r-- | arch/x86/mm/extable.c | 3 |
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, |