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From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org, Boqun Feng <boqun@kernel.org>,
	x86@kernel.org, Thomas Gleixner <tglx@kernel.org>
Subject: Re: [tip: locking/core] locking: Switch to _irq_{disable,enable}() variants in cleanup guards
Date: Mon, 24 Aug 2026 12:47:04 +0200	[thread overview]
Message-ID: <20260824104704.GA4121339@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <178635226387.442315.3868294476114711805.tip-bot2@tip-bot2>

On Mon, Aug 10, 2026 at 08:57:43AM -0000, tip-bot2 for Boqun Feng wrote:
> The following commit has been merged into the locking/core branch of tip:
> 
> Commit-ID:     1b086687483371621e684e2a05b2bcd2cf07b634
> Gitweb:        https://git.kernel.org/tip/1b086687483371621e684e2a05b2bcd2cf07b634
> Author:        Boqun Feng <boqun@kernel.org>
> AuthorDate:    Tue, 04 Aug 2026 09:14:29 -07:00
> Committer:     Peter Zijlstra <peterz@infradead.org>
> CommitterDate: Mon, 10 Aug 2026 10:50:18 +02:00
> 
> locking: Switch to _irq_{disable,enable}() variants in cleanup guards
> 
> The semantics of various IRQ disabling guards match what
> *_irq_{disable,enable}() provide, i.e. the interrupt disabling is
> properly nested, therefore it's OK to switch to use
> *_irq_{disable,enable}() primitives.
> 
> [boqun: Adjust the user-side changes in do_sched_cfs_*_timer() provided
> by Peter and Lyude]
> 
> Signed-off-by: Boqun Feng <boqun@kernel.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: https://patch.msgid.link/20260804161447.84806-8-boqun@kernel.org

I'm going to revert this patch, the rest can stay, but this patch is
broken vs existing code.

Notably, the one found by syzbot is postix_timer_delete() doing
spin_unlock_irq()+spin_lock_irq() inside a scoped_guard(spinlock_irq).

We're going to need stronger tools/debug before trying this again.

  reply	other threads:[~2026-08-24 10:47 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-04 16:14 [PATCH v4 00/17] Refcounted interrupt disable and SpinLockIrq for Rust Boqun Feng
2026-08-04 16:14 ` [PATCH v4 01/17] preempt: Track NMI nesting to separate per-CPU counter Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Joel Fernandes
2026-08-04 16:14 ` [PATCH v4 02/17] preempt: Introduce HARDIRQ_DISABLE_BITS Boqun Feng
2026-08-05  6:31   ` Peter Zijlstra
2026-08-05  6:59     ` Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-04 16:14 ` [PATCH v4 03/17] preempt: Introduce __preempt_count_{sub,add}_return() Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-04 16:14 ` [PATCH v4 04/17] openrisc: Include <linux/cpumask.h> in smp.h Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Lyude Paul
2026-08-04 16:14 ` [PATCH v4 05/17] irq & spin_lock: Add counted interrupt disabling/enabling Boqun Feng
2026-08-04 18:20   ` Boqun Feng
2026-08-04 18:26   ` [PATCH v4.1 " Boqun Feng
2026-08-08 20:48     ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-10  8:57     ` [tip: locking/core] irq,spin_lock: " tip-bot2 for Boqun Feng
2026-08-04 20:51   ` [PATCH v4 05/17] irq & spin_lock: " Shrikanth Hegde
2026-08-04 21:08     ` Boqun Feng
2026-08-05  6:36       ` Peter Zijlstra
2026-08-05  7:07         ` Boqun Feng
2026-08-05  7:09           ` Shrikanth Hegde
2026-08-05  7:19             ` Boqun Feng
2026-08-05 13:53               ` Boqun Feng
2026-08-05 14:10                 ` Shrikanth Hegde
2026-08-05 14:20                   ` Boqun Feng
2026-08-05 14:56                     ` Shrikanth Hegde
2026-08-05 15:11                       ` Boqun Feng
2026-08-05 16:53                         ` Shrikanth Hegde
2026-08-05 17:38                           ` Boqun Feng
2026-08-05 18:07                       ` Boqun Feng
2026-08-04 16:14 ` [PATCH v4 06/17] irq: Add KUnit test for refcounted interrupt enable/disable Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Lyude Paul
2026-08-10  8:57   ` tip-bot2 for Lyude Paul
2026-08-04 16:14 ` [PATCH v4 07/17] locking: Switch to _irq_{disable,enable}() variants in cleanup guards Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-10  8:57   ` tip-bot2 for Boqun Feng
2026-08-24 10:47     ` Peter Zijlstra [this message]
2026-08-24 10:55       ` [PATCH] locking: Revert switching guards to _irq_{disable,enable}() Peter Zijlstra
2026-08-24 11:01         ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2026-08-25  1:33         ` [PATCH] " Boqun Feng
2026-08-04 16:14 ` [PATCH v4 08/17] sched: Remove the unused preempt_offset parameter of __cant_sleep() Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-10  8:57   ` tip-bot2 for Boqun Feng
2026-08-04 16:14 ` [PATCH v4 09/17] sched: Avoid signed comparison of preempt_count() in __cant_migrate() Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-10  8:57   ` tip-bot2 for Boqun Feng
2026-08-04 16:14 ` [PATCH v4 10/17] preempt: Introduce HAS_SEPARATE_PREEMPT_RESCHED_BITS Boqun Feng
2026-08-04 20:11   ` Shrikanth Hegde
2026-08-05  6:54     ` Boqun Feng
2026-08-05  7:15       ` Shrikanth Hegde
2026-08-05  7:27         ` Boqun Feng
2026-08-06  0:58       ` Boqun Feng
2026-08-04 21:09   ` Shrikanth Hegde
2026-08-04 23:14     ` Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-10  8:57   ` tip-bot2 for Boqun Feng
2026-08-04 16:14 ` [PATCH v4 11/17] arm64: sched/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS Boqun Feng
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2026-08-10  8:57   ` tip-bot2 for Boqun Feng
2026-08-04 16:14 ` [PATCH v4 12/17] s390/preempt: " Boqun Feng
2026-08-04 20:27   ` Shrikanth Hegde
2026-08-05  9:42     ` Peter Zijlstra
2026-08-05 12:37       ` Shrikanth Hegde
2026-08-08 20:48   ` [tip: locking/core] " tip-bot2 for Heiko Carstens
2026-08-10  8:57   ` tip-bot2 for Heiko Carstens
2026-08-04 16:14 ` [PATCH v4 13/17] rust: Introduce interrupt module Boqun Feng
2026-08-04 16:14 ` [PATCH v4 14/17] rust: helper: Add spin_{un,}lock_irq_{enable,disable}() helpers Boqun Feng
2026-08-04 16:14 ` [PATCH v4 15/17] rust: sync: Use super::* in spinlock.rs Boqun Feng
2026-08-04 16:14 ` [PATCH v4 16/17] rust: sync: Add SpinLockIrq Boqun Feng
2026-08-04 16:14 ` [PATCH v4 17/17] rust: sync: Introduce SpinLockIrq::lock_with() and friends Boqun Feng

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