From 5cc2db37124bb33914996d6fdbb2ddb3811f2945 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Sat, 21 Dec 2024 21:10:46 +0000 Subject: [PATCH] x86/static-call: Remove early_boot_irqs_disabled check to fix Xen PVH dom0 __static_call_update_early() has a check for early_boot_irqs_disabled, but is used before early_boot_irqs_disabled is set up in start_kernel(). Xen PV has always special cased early_boot_irqs_disabled, but Xen PVH does not and falls over the BUG when booting as dom0. It is very suspect that early_boot_irqs_disabled starts as 0, becomes 1 for a time, then becomes 0 again, but as this needs backporting to fix a breakage in a security fix, dropping the BUG_ON() is the far safer option. Fixes: 0ef8047b737d ("x86/static-call: provide a way to do very early static-call updates") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219620 Reported-by: Alex Zenla Suggested-by: Peter Zijlstra Signed-off-by: Andrew Cooper Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Juergen Gross Acked-by: Peter Zijlstra (Intel) Tested-by: Alex Zenla Link: https://lore.kernel.org/r/20241221211046.6475-1-andrew.cooper3@citrix.com --- arch/x86/kernel/static_call.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c index 9eed0c144dad5..9e51242ed125e 100644 --- a/arch/x86/kernel/static_call.c +++ b/arch/x86/kernel/static_call.c @@ -175,7 +175,6 @@ EXPORT_SYMBOL_GPL(arch_static_call_transform); noinstr void __static_call_update_early(void *tramp, void *func) { BUG_ON(system_state != SYSTEM_BOOTING); - BUG_ON(!early_boot_irqs_disabled); BUG_ON(static_call_initialized); __text_gen_insn(tramp, JMP32_INSN_OPCODE, tramp, func, JMP32_INSN_SIZE); sync_core();