Re: [RFC PATCH 2/2] x86: alternative: Invalidate the cache for updated instructions
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2025-06-11 15:42:50
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the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
On Wed, 11 Jun 2025 10:20:10 -0400 Steven Rostedt [off-list ref] wrote:
If interrupts are enabled when the break point hits and just enters the int3 handler, does that also mean it can schedule?
I added this:
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index c5c897a86418..0f3153322ad2 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c@@ -854,6 +854,8 @@ static bool do_int3(struct pt_regs *regs) { int res; + if (!irqs_disabled()) + printk("IRQS NOT DISABLED\n"); #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP if (kgdb_ll_trap(DIE_INT3, "int3", regs, 0, X86_TRAP_BP, SIGTRAP) == NOTIFY_STOP)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index ecfe7b497cad..2856805d9ed1 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c@@ -2728,6 +2728,12 @@ noinstr int smp_text_poke_int3_handler(struct pt_regs *regs) int ret = 0; void *ip; + if (!irqs_disabled()) { + instrumentation_begin(); + printk("IRQS NOT DISABLED\n"); + instrumentation_end(); + } + if (user_mode(regs)) return 0;
And it didn't trigger when enabling function tracing. Are you sure interrupts are enabled here? -- Steve