linux-kernel - Re: [RFC PATCH 2/2] x86: alternative: Invalidate the cache for updated instructions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250611114243.43a9e3e2@batman.local.home>
Date: Wed, 11 Jun 2025 11:42:43 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...nel.org>,
 Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>, Dave
 Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, Naresh Kamboju
 <naresh.kamboju@...aro.org>, open list <linux-kernel@...r.kernel.org>,
 Linux trace kernel <linux-trace-kernel@...r.kernel.org>,
 lkft-triage@...ts.linaro.org, Stephen Rothwell <sfr@...b.auug.org.au>, Arnd
 Bergmann <arnd@...db.de>, Dan Carpenter <dan.carpenter@...aro.org>, Anders
 Roxell <anders.roxell@...aro.org>
Subject: Re: [RFC PATCH 2/2] x86: alternative: Invalidate the cache for
 updated instructions

On Wed, 11 Jun 2025 10:20:10 -0400
Steven Rostedt <rostedt@...dmis.org> 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