From: Boqun Feng <boqun.feng@gmail.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Waiman Long <longman@redhat.com>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Kent Overstreet <kent.overstreet@linux.dev>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH] lockdep: avoid struct return in lock_stats()
Date: Tue, 17 Jun 2025 22:17:32 -0700 [thread overview]
Message-ID: <aFJL7GW_mdX-VZIR@Mac.home> (raw)
In-Reply-To: <20250610092941.2642847-1-arnd@kernel.org>
On Tue, Jun 10, 2025 at 11:29:21AM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Returning a large structure from the lock_stats() function causes clang
> to have multiple copies of it on the stack and copy between them, which
> can end up exceeding the frame size warning limit:
>
> kernel/locking/lockdep.c:300:25: error: stack frame size (1464) exceeds limit (1280) in 'lock_stats' [-Werror,-Wframe-larger-than]
> 300 | struct lock_class_stats lock_stats(struct lock_class *class)
>
> Change the calling conventions to directly operate on the caller's copy,
> which apparently is what gcc does already.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Queued for more tests and reviews, thanks!
Regards,
Boqun
next prev parent reply other threads:[~2025-06-18 5:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-10 9:29 [PATCH] lockdep: avoid struct return in lock_stats() Arnd Bergmann
2025-06-18 5:17 ` Boqun Feng [this message]
2025-06-18 17:51 ` Andy Shevchenko
2025-06-18 17:59 ` Boqun Feng
2025-07-19 17:40 ` [tip: locking/core] locking/lockdep: Avoid " tip-bot2 for Arnd Bergmann
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