linux-kernel - seqlock: Cure some more scoped

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-next>] [day] [month] [year] [list]

Message-ID: <20251204104332.GG2528459@noisy.programming.kicks-ass.net>
Date: Thu, 4 Dec 2025 11:43:32 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: arnd@...db.de, mingo@...nel.org, oleg@...hat.com
Cc: linux-kernel@...r.kernel.org
Subject: seqlock: Cure some more scoped_seqlock() optimization fails


Arnd reported an x86 randconfig using gcc-15 tripped over
__scoped_seqlock_bug(). Turns out GCC chose not to inline the
scoped_seqlock helper functions and as such was not able to optimize
properly.

Reported-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
For tip/locking/urgent

 include/linux/seqlock.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index a8a8661839b6..221123660e71 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -1224,7 +1224,7 @@ struct ss_tmp {
 	spinlock_t	*lock_irqsave;
 };
 
-static inline void __scoped_seqlock_cleanup(struct ss_tmp *sst)
+static __always_inline void __scoped_seqlock_cleanup(struct ss_tmp *sst)
 {
 	if (sst->lock)
 		spin_unlock(sst->lock);
@@ -1252,7 +1252,7 @@ static inline void __scoped_seqlock_bug(void) { }
 extern void __scoped_seqlock_bug(void);
 #endif
 
-static inline void
+static __always_inline void
 __scoped_seqlock_next(struct ss_tmp *sst, seqlock_t *lock, enum ss_state target)
 {
 	switch (sst->state) {