From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pdx-out-007.esa.us-west-2.outbound.mail-perimeter.amazon.com (pdx-out-007.esa.us-west-2.outbound.mail-perimeter.amazon.com [52.34.181.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 945973DD854; Thu, 6 Aug 2026 09:34:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.34.181.151 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786008843; cv=none; b=WUd66r088o/kATYd8DRbqgaWfrMomFz7yKm/TNSIvyE+stII+kI9tI4vUou4CRPmuUpw9+596GELqBMGlgQTP3FL8EbJoqNV45voXhXcHvcvs6YkYj5f/fRcmIZe9tZ8rJSSe3UExXkD+TbWjsTqwSTKcNdZw2IJoWOOfBDZ6hU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786008843; c=relaxed/simple; bh=zFbSo5+cfeZ6fQN28cNK5NlbX7m1nCUPNznS0RjAeK0=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=m/M0IX9arBTmpU48SPHBhdYL8jm6wN9KnE/dPOOjP9LCB5PKF2yIV/PXxbWrWSZ2vPtxeny6V8GAsKRzFTMWzbhSWgWP3fbnBrs/APExWVBzzi9dQb9a3QB7Z+wTz/A4XJBnWyicAdxH8Z7vgcymBfn05e4zxJgi74/Xz7Iacp0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.de; spf=pass smtp.mailfrom=amazon.de; dkim=pass (2048-bit key) header.d=amazon.de header.i=@amazon.de header.b=A2jDtbF+; arc=none smtp.client-ip=52.34.181.151 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.de header.i=@amazon.de header.b="A2jDtbF+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazoncorp2; t=1786008842; x=1817544842; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=MwvsO7wf1ortKCjyDe8oiLOSqiCPD1EV5AQqurfa1zY=; b=A2jDtbF+g6cefwLRsmGJhK8YXyTmhcrGnRv8Q78r88YUhfz2Tq+ulOF9 Ap/7nFKlwmMEJLuNRWdvRgMqKKo3wI5HzejzyAhnuKE7y3otMbqblkgy7 8ovRyuTzZzhTvDNjwMNdqQINXs3k9XyhbQ9nsQcCjgMOjgFzH543aOPfW BwEOjYOyUwkvTn7jyReLNBSa+dWyDN+tdSEZUtqBm9PULskCEc1XHWzfJ Dkf7TfqzOLsazgxtRhdEZktij/H4a/iN36Be8WURo1h1HNtHrlWedp3+U 2aCeZxBN8eaF/c1KSNXCN50AbGdO/3FVSjwt51iz56ThLM+xq0sYWxYee g==; X-CSE-ConnectionGUID: zyXLMOb0TUWUF3EYg56UxQ== X-CSE-MsgGUID: atcm2zJdQ8yrmnkT78pOSA== X-IronPort-AV: E=Sophos;i="6.25,208,1779148800"; d="scan'208";a="25246332" Received: from ip-10-5-12-219.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.12.219]) by internal-pdx-out-007.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Aug 2026 09:33:59 +0000 Received: from EX19MTAUWA001.ant.amazon.com [205.251.233.236:25423] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.37.134:2525] with esmtp (Farcaster) id 319e3cdf-151c-4654-ac9d-c7a5c1952204; Thu, 6 Aug 2026 09:33:59 +0000 (UTC) X-Farcaster-Flow-ID: 319e3cdf-151c-4654-ac9d-c7a5c1952204 Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWA001.ant.amazon.com (10.250.64.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.45; Thu, 6 Aug 2026 09:33:59 +0000 Received: from dev-dsk-simonlie-1b-ad174abf.eu-west-1.amazon.com (172.19.78.185) by EX19D001UWA001.ant.amazon.com (10.13.138.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.45; Thu, 6 Aug 2026 09:33:56 +0000 From: Simon Liebold To: Thomas Gleixner , Darren Hart , Davidlohr Bueso , =?UTF-8?q?Andr=C3=A9=20Almeida?= , Will Deacon , Waiman Long , Boqun Feng , Simon Liebold , John Stultz , Peter Zijlstra , Ingo Molnar , , CC: Juri Lelli , Connor O'Brien , Metin Kaya , Valentin Schneider , "K Prateek Nayak" Subject: [PATCH 6.12.y 1/2] locking/mutex: Make mutex::wait_lock irq safe Date: Thu, 6 Aug 2026 09:32:58 +0000 Message-ID: <20260806093259.2778358-2-simonlie@amazon.de> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260806093259.2778358-1-simonlie@amazon.de> References: <20260806093259.2778358-1-simonlie@amazon.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D040UWA004.ant.amazon.com (10.13.139.93) To EX19D001UWA001.ant.amazon.com (10.13.138.214) From: Juri Lelli [ Upstream commit 5ec58525a1f1bd6ca8ea778e9df55cd82bc02e11 ] With the proxy-execution series, we traverse the task->mutex->task blocked_on/owner chain in the scheduler core. We do this while holding the rq::lock to keep the structures in place while taking and releasing the alternating lock types. Since the mutex::wait_lock is one of the locks we will take in this way under the rq::lock in the scheduler core, we need to make sure that its usage elsewhere is irq safe. [rebase & fix {un,}lock_wait_lock helpers in ww_mutex.h] Signed-off-by: Juri Lelli Signed-off-by: Connor O'Brien Signed-off-by: John Stultz Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Metin Kaya Reviewed-by: Valentin Schneider Tested-by: K Prateek Nayak Tested-by: Metin Kaya Link: https://lore.kernel.org/r/20241009235352.1614323-3-jstultz@google.com Signed-off-by: Simon Liebold --- kernel/locking/mutex.c | 18 ++++++++++-------- kernel/locking/ww_mutex.h | 21 +++++++++++---------- 2 files changed, 21 insertions(+), 18 deletions(-) diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 6c94da061ec25..cd248d1767eb3 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -578,6 +578,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas DEFINE_WAKE_Q(wake_q); struct mutex_waiter waiter; struct ww_mutex *ww; + unsigned long flags; int ret; if (!use_ww_ctx) @@ -620,7 +621,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas return 0; } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); /* * After waiting to acquire the wait_lock, try again. */ @@ -681,7 +682,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err; } - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); /* Make sure we do wakeups before calling schedule */ wake_up_q(&wake_q); wake_q_init(&wake_q); @@ -706,9 +707,9 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas trace_contention_begin(lock, LCB_F_MUTEX); } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); acquired: __set_current_state(TASK_RUNNING); @@ -734,7 +735,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas if (ww_ctx) ww_mutex_lock_acquired(ww, ww_ctx); - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); wake_up_q(&wake_q); preempt_enable(); return 0; @@ -744,7 +745,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas __mutex_remove_waiter(lock, &waiter); err_early_kill: trace_contention_end(lock, ret); - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); debug_mutex_free_waiter(&waiter); mutex_release(&lock->dep_map, ip); wake_up_q(&wake_q); @@ -915,6 +916,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne struct task_struct *next = NULL; DEFINE_WAKE_Q(wake_q); unsigned long owner; + unsigned long flags; mutex_release(&lock->dep_map, ip); @@ -941,7 +943,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne } } - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, flags); debug_mutex_unlock(lock); if (!list_empty(&lock->wait_list)) { /* get the first entry from the wait-list: */ @@ -959,7 +961,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne __mutex_handoff(lock, next); preempt_disable(); - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); wake_up_q(&wake_q); preempt_enable(); } diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h index a54bd16d0f17d..37f025a096c9d 100644 --- a/kernel/locking/ww_mutex.h +++ b/kernel/locking/ww_mutex.h @@ -70,14 +70,14 @@ __ww_mutex_has_waiters(struct mutex *lock) return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS; } -static inline void lock_wait_lock(struct mutex *lock) +static inline void lock_wait_lock(struct mutex *lock, unsigned long *flags) { - raw_spin_lock(&lock->wait_lock); + raw_spin_lock_irqsave(&lock->wait_lock, *flags); } -static inline void unlock_wait_lock(struct mutex *lock) +static inline void unlock_wait_lock(struct mutex *lock, unsigned long *flags) { - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, *flags); } static inline void lockdep_assert_wait_lock_held(struct mutex *lock) @@ -144,14 +144,14 @@ __ww_mutex_has_waiters(struct rt_mutex *lock) return rt_mutex_has_waiters(&lock->rtmutex); } -static inline void lock_wait_lock(struct rt_mutex *lock) +static inline void lock_wait_lock(struct rt_mutex *lock, unsigned long *flags) { - raw_spin_lock(&lock->rtmutex.wait_lock); + raw_spin_lock_irqsave(&lock->rtmutex.wait_lock, *flags); } -static inline void unlock_wait_lock(struct rt_mutex *lock) +static inline void unlock_wait_lock(struct rt_mutex *lock, unsigned long *flags) { - raw_spin_unlock(&lock->rtmutex.wait_lock); + raw_spin_unlock_irqrestore(&lock->rtmutex.wait_lock, *flags); } static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock) @@ -380,6 +380,7 @@ static __always_inline void ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) { DEFINE_WAKE_Q(wake_q); + unsigned long flags; ww_mutex_lock_acquired(lock, ctx); @@ -408,10 +409,10 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) * Uh oh, we raced in fastpath, check if any of the waiters need to * die or wound us. */ - lock_wait_lock(&lock->base); + lock_wait_lock(&lock->base, &flags); __ww_mutex_check_waiters(&lock->base, ctx, &wake_q); preempt_disable(); - unlock_wait_lock(&lock->base); + unlock_wait_lock(&lock->base, &flags); wake_up_q(&wake_q); preempt_enable(); } -- 2.50.1