From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8526E1D63EF; Tue, 27 May 2025 16:50:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748364629; cv=none; b=XKJutvwVyKqkK0B+lJn1zuAVOhHmImX2sbH+Kp/Fu3KM1e+mqMlQtoREXDGz6rwb5vXCZig/L0Y0tzOjZRdi0HFt2LjYmIldJ9RgLgPUBk1PHwnrGtiVAIQPuCfL49oKRgYZFe2WXDX+nQZm6NBhOMCOwf/cxBN1RSwpDA2jQAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748364629; c=relaxed/simple; bh=l0Qr2+7bQco4D1cDdCKsOrZYj9kc0MbsW+emApl17Z8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iPV0NLMbIiQD06Vx52sIOUDJ7NHleabG3LBXiFwKx52lXdac/N8Ac41wph5//lltb3AGVJH0IVK8lUgCLNQSPP7NOj44mNCT+WwlbXSFwKvNS6xUtnIUdstwA2212VWGGJBCs6UIn0JuN8lRWMsl1G+wIEYUQbEscK3zfhocNxA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EyiD0X+c; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EyiD0X+c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2042C4CEE9; Tue, 27 May 2025 16:50:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748364629; bh=l0Qr2+7bQco4D1cDdCKsOrZYj9kc0MbsW+emApl17Z8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EyiD0X+cC1SjLXOUTwbeWZbyhJmiVFaJdos8TUekP4LWVNG3MajkbjWI3L+VJZt99 2YUtAwebGMOPwdD/9zrafDZYblu36Jxbv0aK7JtIMBQCEwuUhSiMpo2fYhgMtk7uac ZmGfNFl6feOaR3bZ8cCOF50Vyjle9DRO/Ktrb2AY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ryo Takakura , Boqun Feng , Ingo Molnar , Sasha Levin Subject: [PATCH 6.12 085/626] lockdep: Fix wait context check on softirq for PREEMPT_RT Date: Tue, 27 May 2025 18:19:38 +0200 Message-ID: <20250527162448.497691356@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250527162445.028718347@linuxfoundation.org> References: <20250527162445.028718347@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ryo Takakura [ Upstream commit 61c39d8c83e2077f33e0a2c8980a76a7f323f0ce ] Since: 0c1d7a2c2d32 ("lockdep: Remove softirq accounting on PREEMPT_RT.") the wait context test for mutex usage within "in softirq context" fails as it references @softirq_context: | wait context tests | -------------------------------------------------------------------------- | rcu | raw | spin |mutex | -------------------------------------------------------------------------- in hardirq context: ok | ok | ok | ok | in hardirq context (not threaded): ok | ok | ok | ok | in softirq context: ok | ok | ok |FAILED| As a fix, add lockdep map for BH disabled section. This fixes the issue by letting us catch cases when local_bh_disable() gets called with preemption disabled where local_lock doesn't get acquired. In the case of "in softirq context" selftest, local_bh_disable() was being called with preemption disable as it's early in the boot. [ boqun: Move the lockdep annotations into __local_bh_*() to avoid false positives because of unpaired local_bh_disable() reported by Borislav Petkov and Peter Zijlstra, and make bh_lock_map only exist for PREEMPT_RT. ] [ mingo: Restored authorship and improved the bh_lock_map definition. ] Signed-off-by: Ryo Takakura Signed-off-by: Boqun Feng Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250321143322.79651-1-boqun.feng@gmail.com Signed-off-by: Sasha Levin --- kernel/softirq.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/kernel/softirq.c b/kernel/softirq.c index 8c4524ce65faf..00ff176350413 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -126,6 +126,18 @@ static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = { .lock = INIT_LOCAL_LOCK(softirq_ctrl.lock), }; +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static struct lock_class_key bh_lock_key; +struct lockdep_map bh_lock_map = { + .name = "local_bh", + .key = &bh_lock_key, + .wait_type_outer = LD_WAIT_FREE, + .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */ + .lock_type = LD_LOCK_PERCPU, +}; +EXPORT_SYMBOL_GPL(bh_lock_map); +#endif + /** * local_bh_blocked() - Check for idle whether BH processing is blocked * @@ -148,6 +160,8 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt) WARN_ON_ONCE(in_hardirq()); + lock_map_acquire_read(&bh_lock_map); + /* First entry of a task into a BH disabled section? */ if (!current->softirq_disable_cnt) { if (preemptible()) { @@ -211,6 +225,8 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt) WARN_ON_ONCE(in_hardirq()); lockdep_assert_irqs_enabled(); + lock_map_release(&bh_lock_map); + local_irq_save(flags); curcnt = __this_cpu_read(softirq_ctrl.cnt); @@ -261,6 +277,8 @@ static inline void ksoftirqd_run_begin(void) /* Counterpart to ksoftirqd_run_begin() */ static inline void ksoftirqd_run_end(void) { + /* pairs with the lock_map_acquire_read() in ksoftirqd_run_begin() */ + lock_map_release(&bh_lock_map); __local_bh_enable(SOFTIRQ_OFFSET, true); WARN_ON_ONCE(in_interrupt()); local_irq_enable(); -- 2.39.5