From nobody Sat Feb 7 15:06:01 2026 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 780806A8C1 for ; Tue, 7 May 2024 04:55:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715057702; cv=none; b=Ko8IiMhJAgPl0Yz0bjdE67dqEzcAjLE3+/h5uAY9goB5H2mT0gzvNzJbMEJ/Mkjf7jTzHVtWFfAF0xVTRg5a0f43tnkaDLAGc6fjJZmQil2kcWH+CARH8YoSNEa0ndNIPPhf963TajQ4hDXGsS+RzLfj43kUXsE0MLxtCk/mTqE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715057702; c=relaxed/simple; bh=bo+gVaVxjNijWunmE9f5bCNb+eUl23Mllga9rZCgjYs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ZcAyKXPnhfie6CSE6wEiAQTau1aUpOZgNOagvQuPgo/Q8925LMQeQay3S2AdQUMmiwYDQT3BxAk1ri5VhW+UDmAz1M0OH/CKmJRIy9kCwWZY5EchrLUpfw8g46CVXtbQkQRkCp89JXu+QyGN0v7SW5sLRj0kbVlv3xLchbUwILw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=gHph6ZBW; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gHph6ZBW" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2b4330e57b6so3176603a91.2 for ; Mon, 06 May 2024 21:55:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1715057700; x=1715662500; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=WSwAjnZ04uvIvYrm8l/lLv1+BQspgO/0v1ogtObw5dk=; b=gHph6ZBWBXnxvjYJcj+GVBGSHOL+V6IFcYtHU9nqNDVgcgRUNFu2dXtohuz1HKwOSl TwCscv7ZP1BE9iytC35lHbgwEgu5KNxDyOb0IZ7Gmmf3Z9XCOEveg3QnTkfoQYLmRqqJ p6RtXnvzwIn3A4Vr6goEdeaQ9ZjtK3I4DL4pwyJT4gRaaMRvi2FgWW9WMCrq3X3eV7ZA B/RCx8GhQGlCEiGiaoIc8BZ+dMdWKsF75/oIquzFXcnWTa3s6I9XBTAezjJ3omTiB8JK 64F1bf4JkwTFU4+ltvVL+jRBS5rLUXGLHZbv1hfk+1xOFFvfJQt8tTdxLPFSDbgprMG4 9E3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715057700; x=1715662500; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WSwAjnZ04uvIvYrm8l/lLv1+BQspgO/0v1ogtObw5dk=; b=h7BY8Ezsj/b5qbvuYT1j+p+WaXmEfCeiGIXqDt7IGjK65nhqb2jfOKoR4YNSxhrbcA jguIcFy99S1N08EskYf/bbSII/mbaZuthRwueZu/YmYMdEVWPzxpbqVxG5t04wAgRTVP TOmeYjqxcB0+UbPGMRZVIRAZCXmMIOI5TNaypiR1OFTXxMsDLTTxvKrDBy+dJIc90sHt s7MiFSMiw25ePdFujZUZ00dZADI0fGb1lssm7oN6BX2hmKmeGP83/BZvsXyD9wLRyclf bbgIyvY3DRagesEBVKvUlIRxw4iMVXkFp9E4i9+wuiDj9XSmHDOjgDT17v61Xvwco2B1 nV7g== X-Gm-Message-State: AOJu0Yzyi4Zp+gUn5g13yCqVU2XJ5fJyO5Cix53mFmQzZkd6u/j4tRj6 GB22cx1WP2eTbpSdn339yLG1bUPyQqt/tzWYrAbQVKuqGlLmDMSso3gRaEZBthaOLQ0HHt1D0QH tCtD5aTzHAemcSlc3n2IjuGrbR7R8H0/AFF68tSZVD1qaKrct6PMFFmS0bqBg/qFKc0rhw/RUEO Y26vyMGK0Dujhxnm5khutbYKmRoidsXCv5/0fOl/FGjxK9 X-Google-Smtp-Source: AGHT+IF7yVqG/GK7K/5+cWhpXrMrduHe0OomZZSLOu+1d9x/vYuJK4Olkn0mdF6WKdaI8ecHwxYNQ290GQRM X-Received: from jstultz-noogler2.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:600]) (user=jstultz job=sendgmr) by 2002:a17:90a:e387:b0:2b1:6a65:c73a with SMTP id b7-20020a17090ae38700b002b16a65c73amr34556pjz.2.1715057699677; Mon, 06 May 2024 21:54:59 -0700 (PDT) Date: Mon, 6 May 2024 21:54:31 -0700 In-Reply-To: <20240507045450.895430-1-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240507045450.895430-1-jstultz@google.com> X-Mailer: git-send-email 2.45.0.rc1.225.g2a3ae87e7f-goog Message-ID: <20240507045450.895430-3-jstultz@google.com> Subject: [PATCH v10 2/7] locking/mutex: Make mutex::wait_lock irq safe From: John Stultz To: LKML Cc: Juri Lelli , Joel Fernandes , Qais Yousef , Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Steven Rostedt , Ben Segall , Zimuzo Ezeozue , Youssef Esmat , Mel Gorman , Daniel Bristot de Oliveira , Will Deacon , Waiman Long , Boqun Feng , "Paul E. McKenney" , Metin Kaya , Xuewen Yan , K Prateek Nayak , Thomas Gleixner , kernel-team@android.com, Metin Kaya , "Connor O'Brien" , John Stultz Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Juri Lelli mutex::wait_lock might be nested under rq->lock. Make it irq safe then. Cc: Joel Fernandes Cc: Qais Yousef Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Valentin Schneider Cc: Steven Rostedt Cc: Ben Segall Cc: Zimuzo Ezeozue Cc: Youssef Esmat Cc: Mel Gorman Cc: Daniel Bristot de Oliveira Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: "Paul E. McKenney" Cc: Metin Kaya Cc: Xuewen Yan Cc: K Prateek Nayak Cc: Thomas Gleixner Cc: kernel-team@android.com Tested-by: K Prateek Nayak Tested-by: Metin Kaya Reviewed-by: Metin Kaya Reviewed-by: Valentin Schneider Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) [rebase & fix {un,}lock_wait_lock helpers in ww_mutex.h] Signed-off-by: Connor O'Brien Signed-off-by: John Stultz --- v3: * Re-added this patch after it was dropped in v2 which caused lockdep warnings to trip. v7: * Fix function definition for PREEMPT_RT case, as pointed out by Metin Kaya. * Fix incorrect flags handling in PREEMPT_RT case as found by Metin Kaya --- kernel/locking/mutex.c | 18 ++++++++++-------- kernel/locking/ww_mutex.h | 22 +++++++++++----------- 2 files changed, 21 insertions(+), 19 deletions(-) diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4269da1f3ef5..6d843a0978a5 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -578,6 +578,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int st= ate, unsigned int subclas DEFINE_WAKE_Q(wake_q); struct mutex_waiter waiter; struct ww_mutex *ww; + unsigned long flags; int ret; =20 if (!use_ww_ctx) @@ -620,7 +621,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int st= ate, unsigned int subclas return 0; } =20 - 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 st= ate, unsigned int subclas goto err; } =20 - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); /* Make sure we do wakeups before calling schedule */ if (!wake_q_empty(&wake_q)) { wake_up_q(&wake_q); @@ -707,9 +708,9 @@ __mutex_lock_common(struct mutex *lock, unsigned int st= ate, unsigned int subclas trace_contention_begin(lock, LCB_F_MUTEX); } =20 - 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); =20 @@ -735,7 +736,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int st= ate, unsigned int subclas if (ww_ctx) ww_mutex_lock_acquired(ww, ww_ctx); =20 - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, flags); wake_up_q(&wake_q); preempt_enable(); return 0; @@ -745,7 +746,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int st= ate, 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); @@ -916,6 +917,7 @@ static noinline void __sched __mutex_unlock_slowpath(st= ruct mutex *lock, unsigne struct task_struct *next =3D NULL; DEFINE_WAKE_Q(wake_q); unsigned long owner; + unsigned long flags; =20 mutex_release(&lock->dep_map, ip); =20 @@ -942,7 +944,7 @@ static noinline void __sched __mutex_unlock_slowpath(st= ruct mutex *lock, unsigne } } =20 - 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: */ @@ -960,7 +962,7 @@ static noinline void __sched __mutex_unlock_slowpath(st= ruct mutex *lock, unsigne __mutex_handoff(lock, next); =20 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 7189c6631d90..9facc0ddfdd3 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; } =20 -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); } =20 -static inline void unlock_wait_lock(struct mutex *lock) +static inline void unlock_wait_lock(struct mutex *lock, unsigned long *fla= gs) { - raw_spin_unlock(&lock->wait_lock); + raw_spin_unlock_irqrestore(&lock->wait_lock, *flags); } =20 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); } =20 -static inline void lock_wait_lock(struct rt_mutex *lock) +static inline void lock_wait_lock(struct rt_mutex *lock, unsigned long *fl= ags) { - raw_spin_lock(&lock->rtmutex.wait_lock); + raw_spin_lock_irqsave(&lock->rtmutex.wait_lock, *flags); } =20 -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); } =20 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; =20 ww_mutex_lock_acquired(lock, ctx); =20 @@ -408,10 +409,9 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, s= truct 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); - unlock_wait_lock(&lock->base); - + unlock_wait_lock(&lock->base, &flags); wake_up_q(&wake_q); } =20 --=20 2.45.0.rc1.225.g2a3ae87e7f-goog