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From: Borislav Petkov <bp@alien8.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@amacapital.net>, X86 ML <x86@kernel.org>
Subject: [PATCH -v2 2/3] printk: Make the printk*once() variants return a value
Date: Tue,  5 Jul 2016 00:31:26 +0200
Message-ID: <1467671487-10344-3-git-send-email-bp@alien8.de> (raw)
In-Reply-To: <1467671487-10344-1-git-send-email-bp@alien8.de>

From: Borislav Petkov <bp@suse.de>

Have printk*once() return a bool which denotes whether the string was
printed or not so that calling code can react accordingly.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 include/linux/printk.h | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index f4da695fd615..f136b22c7772 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -108,11 +108,14 @@ struct va_format {
  * Dummy printk for disabled debugging statements to use whilst maintaining
  * gcc's format checking.
  */
-#define no_printk(fmt, ...)			\
-do {						\
-	if (0)					\
-		printk(fmt, ##__VA_ARGS__);	\
-} while (0)
+#define no_printk(fmt, ...)				\
+({							\
+	do {						\
+		if (0)					\
+			printk(fmt, ##__VA_ARGS__);	\
+	} while (0);					\
+	0;						\
+})
 
 #ifdef CONFIG_EARLY_PRINTK
 extern asmlinkage __printf(1, 2)
@@ -309,20 +312,24 @@ extern asmlinkage void dump_stack(void) __cold;
 #define printk_once(fmt, ...)					\
 ({								\
 	static bool __print_once __read_mostly;			\
+	bool __ret_print_once = !__print_once;			\
 								\
 	if (!__print_once) {					\
 		__print_once = true;				\
 		printk(fmt, ##__VA_ARGS__);			\
 	}							\
+	unlikely(__ret_print_once);				\
 })
 #define printk_deferred_once(fmt, ...)				\
 ({								\
 	static bool __print_once __read_mostly;			\
+	bool __ret_print_once = !__print_once;			\
 								\
 	if (!__print_once) {					\
 		__print_once = true;				\
 		printk_deferred(fmt, ##__VA_ARGS__);		\
 	}							\
+	unlikely(__ret_print_once);				\
 })
 #else
 #define printk_once(fmt, ...)					\
-- 
2.7.3

  parent reply index

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-04 22:31 [PATCH -v2 0/3] x86/MSR: Improve unhandled MSR access error message Borislav Petkov
2016-07-04 22:31 ` [PATCH -v2 1/3] x86/dumpstack: Honor supplied @regs arg Borislav Petkov
2016-07-04 22:31 ` Borislav Petkov [this message]
2016-07-08 12:08   ` [tip:x86/debug] printk: Make the printk*once() variants return a value tip-bot for Borislav Petkov
2016-07-09  2:40     ` Joe Perches
2016-07-09  7:50       ` Borislav Petkov
2016-07-09 17:56         ` Joe Perches
2016-07-10  6:49           ` Borislav Petkov
2016-07-10  8:23             ` Joe Perches
2016-07-10 12:06               ` Borislav Petkov
2016-07-10 12:33                 ` Joe Perches
2016-07-04 22:31 ` [PATCH -v2 3/3] x86/dumpstack: Add show_stack_regs() and use it Borislav Petkov
2016-07-08 12:08   ` [tip:x86/debug] " tip-bot for Borislav Petkov
2016-07-06 12:58 ` [PATCH -v2 0/3] x86/MSR: Improve unhandled MSR access error message Andy Lutomirski
2016-07-06 13:11   ` Borislav Petkov
  -- strict thread matches above, loose matches on Subject: below --
2016-06-24  8:30 [PATCH " Borislav Petkov
2016-06-24  8:30 ` [PATCH 2/3] printk: Make the printk*once() variants return a value Borislav Petkov
2016-06-24 13:43   ` Joe Perches
2016-06-25 11:01     ` Borislav Petkov
2016-06-27  9:15       ` [PATCH -v2 " Borislav Petkov
2016-06-16  0:28 [PATCH 00/13] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-16  0:28 ` [PATCH 01/13] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-16  0:28 ` [PATCH 02/13] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski
2016-06-16  0:28 ` [PATCH 03/13] x86/cpa: Warn if kernel_unmap_pages_in_pgd is used inappropriately Andy Lutomirski
2016-06-16  0:28 ` [PATCH 04/13] mm: Track NR_KERNEL_STACK in pages instead of number of stacks Andy Lutomirski
2016-06-16 11:10   ` Vladimir Davydov
2016-06-16 17:21     ` Andy Lutomirski
2016-06-16 19:20       ` Andy Lutomirski
2016-06-16 15:33   ` Josh Poimboeuf
2016-06-16 17:39     ` Andy Lutomirski
2016-06-16 19:39       ` Josh Poimboeuf
2016-06-16  0:28 ` [PATCH 05/13] mm: Move memcg stack accounting to account_kernel_stack Andy Lutomirski
2016-06-16  0:28 ` [PATCH 06/13] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-16 17:25   ` Kees Cook
2016-06-16 17:37     ` Andy Lutomirski
2016-06-16  0:28 ` [PATCH 07/13] x86/die: Don't try to recover from an OOPS on a non-default stack Andy Lutomirski
2016-06-16  0:28 ` [PATCH 08/13] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-16 17:50   ` Josh Poimboeuf
2016-06-16 17:57     ` Andy Lutomirski
2016-06-16  0:28 ` [PATCH 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-16 11:56   ` Borislav Petkov
2016-07-08 12:07   ` [tip:x86/debug] x86/dumpstack: Honor supplied @regs arg tip-bot for Andy Lutomirski
2016-06-16  0:28 ` [PATCH 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-16 18:16   ` Josh Poimboeuf
2016-06-16 18:22     ` Andy Lutomirski
2016-06-16 18:33       ` Josh Poimboeuf
2016-06-16 18:37         ` Andy Lutomirski
2016-06-16 18:54           ` Josh Poimboeuf
2016-06-16  0:28 ` [PATCH 11/13] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski
2016-06-16  0:28 ` [PATCH 12/13] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-16  4:17   ` Mika Penttilä
2016-06-16  5:33     ` Andy Lutomirski
2016-06-16 13:11       ` [kernel-hardening] " Rik van Riel
2016-06-16  0:28 ` [PATCH 13/13] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski
2016-06-16  6:05 ` [PATCH 00/13] Virtually mapped stacks with guard pages (x86, core) Heiko Carstens
2016-06-16 17:50   ` Andy Lutomirski
2016-06-16 18:14     ` Andy Lutomirski
2016-06-16 21:27       ` Andy Lutomirski
2016-06-17  3:58   ` Andy Lutomirski
2016-06-17  7:27     ` Heiko Carstens
2016-06-17 17:38       ` Andy Lutomirski
2016-06-20  5:58         ` Heiko Carstens
2016-06-20  6:01           ` Andy Lutomirski
2016-06-20  7:07             ` Heiko Carstens
2016-06-16 17:24 ` Kees Cook

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