linux-kernel - [tip:x86/urgent] x86/mm: Clean up the printk()s in show_fault

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Message-ID: <tip-d79d0d8ad0cb3d782b41631dfeac8eb05e414bcd@git.kernel.org>
Date:   Wed, 27 Jun 2018 06:18:51 -0700
From:   tip-bot for Dmitry Vyukov <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     torvalds@...ux-foundation.org, mingo@...nel.org,
        tglx@...utronix.de, linux-kernel@...r.kernel.org, hpa@...or.com,
        joe@...ches.com, dvyukov@...gle.com, peterz@...radead.org
Subject: [tip:x86/urgent] x86/mm: Clean up the printk()s in
 show_fault_oops()

Commit-ID:  d79d0d8ad0cb3d782b41631dfeac8eb05e414bcd
Gitweb:     https://git.kernel.org/tip/d79d0d8ad0cb3d782b41631dfeac8eb05e414bcd
Author:     Dmitry Vyukov <dvyukov@...gle.com>
AuthorDate: Wed, 27 Jun 2018 11:07:15 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 27 Jun 2018 14:08:11 +0200

x86/mm: Clean up the printk()s in show_fault_oops()

- Remove 'nx_warning' and 'smep_warning', which are just pointless obfuscation.
- Also convert to pr_crit().

Suggested-by: Joe Perches <joe@...ches.com>
Signed-off-by: Dmitry Vyukov <dvyukov@...gle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20180627090715.28076-1-dvyukov@gmail.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/mm/fault.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index ee85766e6329..2aafa6ab6103 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -641,11 +641,6 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
 	return 0;
 }
 
-static const char nx_warning[] = KERN_CRIT
-"kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n";
-static const char smep_warning[] = KERN_CRIT
-"unable to execute userspace code (SMEP?) (uid: %d)\n";
-
 static void
 show_fault_oops(struct pt_regs *regs, unsigned long error_code,
 		unsigned long address)
@@ -664,11 +659,13 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code,
 		pte = lookup_address_in_pgd(pgd, address, &level);
 
 		if (pte && pte_present(*pte) && !pte_exec(*pte))
-			printk(nx_warning, from_kuid(&init_user_ns, current_uid()));
+			pr_crit("kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n",
+				from_kuid(&init_user_ns, current_uid()));
 		if (pte && pte_present(*pte) && pte_exec(*pte) &&
 				(pgd_flags(*pgd) & _PAGE_USER) &&
 				(__read_cr4() & X86_CR4_SMEP))
-			printk(smep_warning, from_kuid(&init_user_ns, current_uid()));
+			pr_crit("unable to execute userspace code (SMEP?) (uid: %d)\n",
+				from_kuid(&init_user_ns, current_uid()));
 	}
 
 	pr_alert("BUG: unable to handle kernel %s at %px\n",