linux-kernel - [PATCH v2] locking/local_lock: s/l/__l/ and s/tl/_

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>] [day] [month] [year] [list]
Message-Id: <20250925-local_lock_internal_fix_shadow-v2-1-d3b85ee775a4@kernel.org>
Date: Thu, 25 Sep 2025 03:03:23 +0900
From: Vincent Mailhol <mailhol@...nel.org>
To: Vlastimil Babka <vbabka@...e.cz>, Shakeel Butt <shakeel.butt@...ux.dev>, 
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>, 
 Alexei Starovoitov <ast@...nel.org>, 
 Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Vincent Mailhol <mailhol@...nel.org>
Subject: [PATCH v2] locking/local_lock: s/l/__l/ and s/tl/__tl/ to reduce
 risk of shadowing

The Linux kernel coding style [1] advises to avoid common variable
names in function-like macros to reduce the risk of collisions.

Throughout local_lock_internal.h, several macros use the rather common
variable names 'l' and 'tl'. This already resulted in an actual
collision: the __local_lock_acquire() function like macro is currently
shadowing the parameter 'l' of the:

  class_##_name##_t class_##_name##_constructor(_type *l)

function factory from linux/cleanup.h.

Rename the variable 'l' to '__l' and the variable 'tl' to '__tl'
throughout the file to fix the current name collision and to prevent
future ones.

[1] https://www.kernel.org/doc/html/latest/process/coding-style.html#macros-enums-and-rtl

Signed-off-by: Vincent Mailhol <mailhol@...nel.org>
---
Changes in v2:

  - __lock conflicted with an existing definition in lockdep.c. Use
    instead __l (and also, to keep things consistent, use __tl instead
    of tl for the trylock).

  - Apply the renaming to the entire file and not just to
    __local_lock_acquire().

  - Rewrite the patch description accordingly.

Link to v1: https://lore.kernel.org/r/20250923-local_lock_internal_fix_shadow-v1-1-14e313c88a46@kernel.org
---
 include/linux/local_lock_internal.h | 56 ++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index d80b5306a2c0ccf95a3405b6b947b5f1f9a3bd38..a80b3fd7552376cd926aeaac8f53bcc44c8d2173 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -96,18 +96,18 @@ do {								\
 
 #define __local_lock_acquire(lock)					\
 	do {								\
-		local_trylock_t *tl;					\
-		local_lock_t *l;					\
+		local_trylock_t *__tl;					\
+		local_lock_t *__l;					\
 									\
-		l = (local_lock_t *)(lock);				\
-		tl = (local_trylock_t *)l;				\
+		__l = (local_lock_t *)(lock);				\
+		__tl = (local_trylock_t *)__l;				\
 		_Generic((lock),					\
 			local_trylock_t *: ({				\
-				lockdep_assert(tl->acquired == 0);	\
-				WRITE_ONCE(tl->acquired, 1);		\
+				lockdep_assert(__tl->acquired == 0);	\
+				WRITE_ONCE(__tl->acquired, 1);		\
 			}),						\
 			local_lock_t *: (void)0);			\
-		local_lock_acquire(l);					\
+		local_lock_acquire(__l);				\
 	} while (0)
 
 #define __local_lock(lock)					\
@@ -130,50 +130,50 @@ do {								\
 
 #define __local_trylock(lock)					\
 	({							\
-		local_trylock_t *tl;				\
+		local_trylock_t *__tl;				\
 								\
 		preempt_disable();				\
-		tl = (lock);					\
-		if (READ_ONCE(tl->acquired)) {			\
+		__tl = (lock);					\
+		if (READ_ONCE(__tl->acquired)) {		\
 			preempt_enable();			\
-			tl = NULL;				\
+			__tl = NULL;				\
 		} else {					\
-			WRITE_ONCE(tl->acquired, 1);		\
+			WRITE_ONCE(__tl->acquired, 1);		\
 			local_trylock_acquire(			\
-				(local_lock_t *)tl);		\
+				(local_lock_t *)__tl);		\
 		}						\
-		!!tl;						\
+		!!__tl;						\
 	})
 
 #define __local_trylock_irqsave(lock, flags)			\
 	({							\
-		local_trylock_t *tl;				\
+		local_trylock_t *__tl;				\
 								\
 		local_irq_save(flags);				\
-		tl = (lock);					\
-		if (READ_ONCE(tl->acquired)) {			\
+		__tl = (lock);					\
+		if (READ_ONCE(__tl->acquired)) {		\
 			local_irq_restore(flags);		\
-			tl = NULL;				\
+			__tl = NULL;				\
 		} else {					\
-			WRITE_ONCE(tl->acquired, 1);		\
+			WRITE_ONCE(__tl->acquired, 1);		\
 			local_trylock_acquire(			\
-				(local_lock_t *)tl);		\
+				(local_lock_t *)__tl);		\
 		}						\
-		!!tl;						\
+		!!__tl;						\
 	})
 
 #define __local_lock_release(lock)					\
 	do {								\
-		local_trylock_t *tl;					\
-		local_lock_t *l;					\
+		local_trylock_t *__tl;					\
+		local_lock_t *__l;					\
 									\
-		l = (local_lock_t *)(lock);				\
-		tl = (local_trylock_t *)l;				\
-		local_lock_release(l);					\
+		__l = (local_lock_t *)(lock);				\
+		__tl = (local_trylock_t *)__l;				\
+		local_lock_release(__l);				\
 		_Generic((lock),					\
 			local_trylock_t *: ({				\
-				lockdep_assert(tl->acquired == 1);	\
-				WRITE_ONCE(tl->acquired, 0);		\
+				lockdep_assert(__tl->acquired == 1);	\
+				WRITE_ONCE(__tl->acquired, 0);		\
 			}),						\
 			local_lock_t *: (void)0);			\
 	} while (0)

---
base-commit: cec1e6e5d1ab33403b809f79cd20d6aff124ccfe
change-id: 20250923-local_lock_internal_fix_shadow-2e2a24e95e76

Best regards,
-- 
Vincent Mailhol <mailhol@...nel.org>