From c6ef89421e236d75693ae968d80d44a52409889d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 1 Sep 2017 11:04:56 +0200 Subject: [PATCH] x86/idt: Fix the X86_TRAP_BP gate Andrei Vagin reported a CRIU regression and bisected it back to: 90f6225fba0c ("x86/idt: Move IST stack based traps to table init") This table init conversion loses the system-gate property of X86_TRAP_BP and erroneously moves it from DPL3 to DPL0. Fix it. Reported-by: Andrei Vagin Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Cc: dvlasenk@redhat.com Cc: linux-tip-commits@vger.kernel.org Cc: peterz@infradead.org Cc: brgerst@gmail.com Cc: rostedt@goodmis.org Cc: bp@alien8.de Cc: luto@kernel.org Cc: jpoimboe@redhat.com Cc: Cyrill Gorcunov Cc: torvalds@linux-foundation.org Cc: tip-bot for Jacob Shin Link: http://lkml.kernel.org/r/20170901082630.xvyi5bwk6etmppqc@gmail.com --- arch/x86/kernel/idt.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 61b490c69250..6107ee1cb8d5 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -44,6 +44,10 @@ struct idt_data { #define ISTG(_vector, _addr, _ist) \ G(_vector, _addr, _ist, GATE_INTERRUPT, DPL0, __KERNEL_CS) +/* System interrupt gate with interrupt stack */ +#define SISTG(_vector, _addr, _ist) \ + G(_vector, _addr, _ist, GATE_INTERRUPT, DPL3, __KERNEL_CS) + /* Task gate */ #define TSKG(_vector, _gdt) \ G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3) @@ -181,7 +185,7 @@ gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss; static const __initdata struct idt_data ist_idts[] = { ISTG(X86_TRAP_DB, debug, DEBUG_STACK), ISTG(X86_TRAP_NMI, nmi, NMI_STACK), - ISTG(X86_TRAP_BP, int3, DEBUG_STACK), + SISTG(X86_TRAP_BP, int3, DEBUG_STACK), ISTG(X86_TRAP_DF, double_fault, DOUBLEFAULT_STACK), #ifdef CONFIG_X86_MCE ISTG(X86_TRAP_MC, &machine_check, MCE_STACK), -- 2.20.1