From nobody Mon Sep 28 08:46:35 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 925DE3ED3D8; Mon, 24 Aug 2026 11:01:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787569286; cv=none; b=nzGWNeryuO2IT9Qie0Acy8JZc+NEN33bW7CWhBC3npgLYz782RaRa00i0nBarSz/9psibWlgqzMnWtnoBz8Dum/pR7ZAx7Mzi2rB4nP3rOOKNxcVlkMMariDCSHdce2i6ujl1UWZ8zUPcz7mnrlcRsiAW+ylk1UDR39/ebCtZEw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787569286; c=relaxed/simple; bh=uzlDb+oVWtLQgVNzxOGz9WsBSGU0iZYD6Baaq+4eG0Q=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=tS9/mqG7ZbSPrtQUMfozCtySnRZXVEUPw6u++rAnCJRAppxs3254tiG9g5VZxDo1wsg6tmeYNiimUyuWM/9DCvL11WlhAXq/nJE957naWLj8nsdR0kQ7aafqOsm4KPUrTWymobrrhY5cwAeYxDdHzYew/SP+Vd9K+moD3Qiv7Wk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=0iJPV8HW; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=fX0GikIO; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="0iJPV8HW"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="fX0GikIO" Date: Mon, 24 Aug 2026 11:01:20 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1787569282; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wM/3Kh5+eSxzTJue9ExuSuWJGHI9U6or0L4LSb7bo1Q=; b=0iJPV8HWCCNq9u6pBBV6SVpeMFdiHmCgomDjV0ILlqOuB+aaqG++iuCZQI/upXGzrk/4WP tfJ1zSnjbJXC3BoOPcZ+TTmsrhcHtptM1DcrSjLdGBBgISwu1el5CEoHHNI7g+Ncofjwwj FF2g8eHbSDH8m7pDR1R8jzWLkyCH6CA4XzMDVHJQFPb75Hg/U0x3WkIoRpmIYKTPjw3CLi +a5j395E69wWXWPvhi4ZGulZjcexuBBR5kAmF7U01flTQtTp7EOdBer9Cm5nhgxZ4McZ99 2AmKp2Xu7HJ/PGF15EmK/A2h1Zl2lG3JzbG53Sil6J4jjHOc6wM3+NDwQFDtjA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1787569282; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wM/3Kh5+eSxzTJue9ExuSuWJGHI9U6or0L4LSb7bo1Q=; b=fX0GikIOmHH9wBw0rF2KTj5h64Zj3xIhjgqqHebQHDPkh0AvGsC07TzBQVEdHhMvmh0h8K NXIaZL0hDHKKyVDg== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/urgent] locking: Revert switching guards to _irq_{disable,enable}() Cc: "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20260824105523.GA4121620@noisy.programming.kicks-ass.net> References: <20260824105523.GA4121620@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <178756928066.2638944.6226149617281646492.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the locking/urgent branch of tip: Commit-ID: 46094a7708b7945cb7eba9eb887e3ea9757440a7 Gitweb: https://git.kernel.org/tip/46094a7708b7945cb7eba9eb887e3ea97= 57440a7 Author: Peter Zijlstra AuthorDate: Mon, 24 Aug 2026 12:49:10 +02:00 Committer: Peter Zijlstra CommitterDate: Mon, 24 Aug 2026 12:58:54 +02:00 locking: Revert switching guards to _irq_{disable,enable}() Revert commit 1b0866874833 ("locking: Switch to _irq_{disable,enable}() variants in cleanup guards"). While the guards are properly nested, not all wrapped code is nice, as alre= ady highlighted by that fair.c hunk. Syzbot found another instance of this pattern in posix_timer_delete(), which does spin_unlock_irq()+spin_lock_irq() inside scoped_guard(spinlock_irq). Combined with this patch, that goes sideways most spectacular. Undo this until we've developed stronger tools / debug for such issues. Fixes: 1b0866874833 ("locking: Switch to _irq_{disable,enable}() variants i= n cleanup guards") Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260824105523.GA4121620%40noisy.programming= .kicks-ass.net --- include/linux/spinlock.h | 26 ++++++++++++++------------ kernel/sched/fair.c | 12 ++++++------ 2 files changed, 20 insertions(+), 18 deletions(-) diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 799a8f7..3d405cc 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -572,12 +572,12 @@ DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_nested, __acq= uires(_T), __releases(*(raw #define class_raw_spinlock_nested_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(= raw_spinlock_nested, _T) =20 DEFINE_LOCK_GUARD_1(raw_spinlock_irq, raw_spinlock_t, - raw_spin_lock_irq_disable(_T->lock), - raw_spin_unlock_irq_enable(_T->lock)) + raw_spin_lock_irq(_T->lock), + raw_spin_unlock_irq(_T->lock)) DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irq, __acquires(_T), __releases(*(= raw_spinlock_t **)_T)) #define class_raw_spinlock_irq_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw= _spinlock_irq, _T) =20 -DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irq, _try, raw_spin_trylock_irq_disa= ble(_T->lock)) +DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irq, _try, raw_spin_trylock_irq(_T->= lock)) DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irq_try, __acquires(_T), __release= s(*(raw_spinlock_t **)_T)) #define class_raw_spinlock_irq_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS= (raw_spinlock_irq_try, _T) =20 @@ -592,13 +592,14 @@ DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_bh_try, __acq= uires(_T), __releases(*(raw #define class_raw_spinlock_bh_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(= raw_spinlock_bh_try, _T) =20 DEFINE_LOCK_GUARD_1(raw_spinlock_irqsave, raw_spinlock_t, - raw_spin_lock_irq_disable(_T->lock), - raw_spin_unlock_irq_enable(_T->lock)) + raw_spin_lock_irqsave(_T->lock, _T->flags), + raw_spin_unlock_irqrestore(_T->lock, _T->flags), + unsigned long flags) DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irqsave, __acquires(_T), __release= s(*(raw_spinlock_t **)_T)) #define class_raw_spinlock_irqsave_constructor(_T) WITH_LOCK_GUARD_1_ATTRS= (raw_spinlock_irqsave, _T) =20 DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irqsave, _try, - raw_spin_trylock_irq_disable(_T->lock)) + raw_spin_trylock_irqsave(_T->lock, _T->flags)) DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irqsave_try, __acquires(_T), __rel= eases(*(raw_spinlock_t **)_T)) #define class_raw_spinlock_irqsave_try_constructor(_T) WITH_LOCK_GUARD_1_A= TTRS(raw_spinlock_irqsave_try, _T) =20 @@ -617,13 +618,13 @@ DECLARE_LOCK_GUARD_1_ATTRS(spinlock_try, __acquires(_= T), __releases(*(spinlock_t #define class_spinlock_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinloc= k_try, _T) =20 DEFINE_LOCK_GUARD_1(spinlock_irq, spinlock_t, - spin_lock_irq_disable(_T->lock), - spin_unlock_irq_enable(_T->lock)) + spin_lock_irq(_T->lock), + spin_unlock_irq(_T->lock)) DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irq, __acquires(_T), __releases(*(spin= lock_t **)_T)) #define class_spinlock_irq_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinloc= k_irq, _T) =20 DEFINE_LOCK_GUARD_1_COND(spinlock_irq, _try, - spin_trylock_irq_disable(_T->lock)) + spin_trylock_irq(_T->lock)) DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irq_try, __acquires(_T), __releases(*(= spinlock_t **)_T)) #define class_spinlock_irq_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spi= nlock_irq_try, _T) =20 @@ -639,13 +640,14 @@ DECLARE_LOCK_GUARD_1_ATTRS(spinlock_bh_try, __acquire= s(_T), __releases(*(spinloc #define class_spinlock_bh_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spin= lock_bh_try, _T) =20 DEFINE_LOCK_GUARD_1(spinlock_irqsave, spinlock_t, - spin_lock_irq_disable(_T->lock), - spin_unlock_irq_enable(_T->lock)) + spin_lock_irqsave(_T->lock, _T->flags), + spin_unlock_irqrestore(_T->lock, _T->flags), + unsigned long flags) DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irqsave, __acquires(_T), __releases(*(= spinlock_t **)_T)) #define class_spinlock_irqsave_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spi= nlock_irqsave, _T) =20 DEFINE_LOCK_GUARD_1_COND(spinlock_irqsave, _try, - spin_trylock_irq_disable(_T->lock)) + spin_trylock_irqsave(_T->lock, _T->flags)) DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irqsave_try, __acquires(_T), __release= s(*(spinlock_t **)_T)) #define class_spinlock_irqsave_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS= (spinlock_irqsave_try, _T) =20 diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6d881e5..8dff370 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7253,7 +7253,7 @@ static bool distribute_cfs_runtime(struct cfs_bandwid= th *cfs_b) * period the timer is deactivated until scheduling resumes; cfs_b->idle is * used to track this state. */ -static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int over= run) +static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int over= run, unsigned long flags) __must_hold(&cfs_b->lock) { int throttled; @@ -7288,10 +7288,10 @@ static int do_sched_cfs_period_timer(struct cfs_ban= dwidth *cfs_b, int overrun) * This check is repeated as we release cfs_b->lock while we unthrottle. */ while (throttled && cfs_b->runtime > 0) { - raw_spin_unlock_irq_enable(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); /* we can't nest cfs_b->lock while distributing bandwidth */ throttled =3D distribute_cfs_runtime(cfs_b); - raw_spin_lock_irq_disable(&cfs_b->lock); + raw_spin_lock_irqsave(&cfs_b->lock, flags); } =20 /* @@ -7399,7 +7399,7 @@ static __always_inline void return_cfs_rq_runtime(str= uct cfs_rq *cfs_rq) static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) { /* confirm we're still not at a refresh boundary */ - scoped_guard(raw_spinlock_irq, &cfs_b->lock) { + scoped_guard(raw_spinlock_irqsave, &cfs_b->lock) { u64 runtime =3D 0, slice =3D sched_cfs_bandwidth_slice(); =20 cfs_b->slack_started =3D false; @@ -7484,14 +7484,14 @@ static enum hrtimer_restart sched_cfs_period_timer(= struct hrtimer *timer) int idle =3D 0; int count =3D 0; =20 - guard(raw_spinlock_irq)(&cfs_b->lock); + CLASS(raw_spinlock_irqsave, cfsb_guard)(&cfs_b->lock); =20 for (;;) { overrun =3D hrtimer_forward_now(timer, cfs_b->period); if (!overrun) break; =20 - idle =3D do_sched_cfs_period_timer(cfs_b, overrun); + idle =3D do_sched_cfs_period_timer(cfs_b, overrun, cfsb_guard.flags); =20 if (++count > 3) { u64 new, old =3D ktime_to_ns(cfs_b->period);