Commit b8347c21 authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Ingo Molnar
Browse files

x86/debug: Handle warnings before the notifier chain, to fix KGDB crash



 ("x86/debug: Implement __WARN() using UD0")

turned warnings into UD0, but the fixup code only runs after the
notify_die() chain. This is a problem, in particular, with kgdb,
which kicks in as if it was a BUG().

Fix this by running the fixup code before the notifier chain in
the invalid op handler path.
Signed-off-by: default avatarAlexander Shishkin <>
Tested-by: default avatarIlya Dryomov <>
Acked-by: default avatarDaniel Thompson <>
Acked-by: default avatarThomas Gleixner <>
Cc: Jason Wessel <>
Cc: Arjan van de Ven <>
Cc: Borislav Petkov <>
Cc: Linus Torvalds <>
Cc: Peter Zijlstra <>
Cc: Richard Weinberger <>
Cc: <> # v4.12+

Signed-off-by: default avatarIngo Molnar <>
parent be739f4b
......@@ -209,9 +209,6 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
if (fixup_exception(regs, trapnr))
return 0;
if (fixup_bug(regs, trapnr))
return 0;
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = trapnr;
die(str, regs, error_code);
......@@ -292,6 +289,13 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
* WARN*()s end up here; fix them up before we call the
* notifier chain.
if (!user_mode(regs) && fixup_bug(regs, trapnr))
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
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