x86/entry: Treat BUG/WARN as NMI-like entries

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BUG/WARN are cleverly optimized using UD2 to handle the BUG/WARN out of
line in an exception fixup.

But if BUG or WARN is issued in a funny RCU context, then the
idtentry_enter...() path might helpfully WARN that the RCU context is
invalid, which results in infinite recursion.

Split the BUG/WARN handling into an nmi_enter()/nmi_exit() path in
exc_invalid_op() to increase the chance to survive the experience.

[ tglx: Make the declaration match the implementation ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/f8fe40e0088749734b4435b554f73eee53dcf7a8.1591932307.git.luto@kernel.org

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Andy Lutomirski 2020-06-11 20:26:38 -07:00 • committed by Thomas Gleixner

parent f0178fc01f

commit 15a416e8aa

3 changed files with 52 additions and 29 deletions

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2

arch/x86/include/asm/idtentry.h

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64

arch/x86/kernel/traps.c

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15

arch/x86/mm/extable.c

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