From 15a416e8aaa758b5534f64a3972dae05275bc225 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 11 Jun 2020 20:26:38 -0700 Subject: x86/entry: Treat BUG/WARN as NMI-like entries 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 Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/f8fe40e0088749734b4435b554f73eee53dcf7a8.1591932307.git.luto@kernel.org --- arch/x86/include/asm/idtentry.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index d203c541a65a..2fc6b0c58341 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -543,7 +543,6 @@ SYM_CODE_END(spurious_entries_start) DECLARE_IDTENTRY(X86_TRAP_DE, exc_divide_error); DECLARE_IDTENTRY(X86_TRAP_OF, exc_overflow); DECLARE_IDTENTRY(X86_TRAP_BR, exc_bounds); -DECLARE_IDTENTRY(X86_TRAP_UD, exc_invalid_op); DECLARE_IDTENTRY(X86_TRAP_NM, exc_device_not_available); DECLARE_IDTENTRY(X86_TRAP_OLD_MF, exc_coproc_segment_overrun); DECLARE_IDTENTRY(X86_TRAP_SPURIOUS, exc_spurious_interrupt_bug); @@ -561,6 +560,7 @@ DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_GP, exc_general_protection); DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_AC, exc_alignment_check); /* Raw exception entries which need extra work */ +DECLARE_IDTENTRY_RAW(X86_TRAP_UD, exc_invalid_op); DECLARE_IDTENTRY_RAW(X86_TRAP_BP, exc_int3); DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_PF, exc_page_fault); -- cgit v1.2.3