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 23FD717BB6; Mon, 2 Jun 2025 14:53:45 +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=1748876025; cv=none; b=JX2fga6s09iFHd/GeFqQeLcQIAQXG1mjr+0LQLmvxxszJSxIQRYL4n1CAt6Dh1mzWZk3ujLbGZTkXCZS2ZUilaFrAWT/QdfZG0KCbb1JXuyRsH1EO6bU7+6LhiHJKXLhmoOnNJ8l9kDT+EXD9Gkt9wErggdYZePB7dz3EKDrwlc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748876025; c=relaxed/simple; bh=SJHH0fU1AibIgHiYRV2p/8sS/5nTUNlTAJ1NH/hy/ds=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eEpmSX93d6gzBZU8RmIihJ223df4i2L1fNqxaVyOkrc6XhxN588h+5/SaKNDV7WbTeFBBu6qFHkW2y1+JCtx8CF3m5ZZjDOHRqlKE5oI/MAj0hVOvxJ+FyGo295nKvnC+sW9mqRKbVJOgv7TyiCf4QkpanpPHQ0hvqRC9kAen+g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pJGdG76Q; 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="pJGdG76Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85DC3C4CEEB; Mon, 2 Jun 2025 14:53:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748876025; bh=SJHH0fU1AibIgHiYRV2p/8sS/5nTUNlTAJ1NH/hy/ds=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pJGdG76QUUSWAsxF4Hqf7qQIaz1cSTI2mbke1fy3ddUt0/DPHNwWjYaxXxzw9lgJ7 eWSGwqHD7AaTQVlgNyTHwW63/kOAz6/2F93qmxazo3h2WNjUWtwovFWCvD7Exsot7O E2DBMWXq/SRVCqo9ECpN1O8WbmTITC4a5fs+4JtA= 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 5.15 020/207] lockdep: Fix wait context check on softirq for PREEMPT_RT Date: Mon, 2 Jun 2025 15:46:32 +0200 Message-ID: <20250602134259.561959939@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134258.769974467@linuxfoundation.org> References: <20250602134258.769974467@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 5.15-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 dc60f0c66a25f..d63d827da2d6a 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -140,6 +140,18 @@ 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 * @@ -162,6 +174,8 @@ 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()) { @@ -225,6 +239,8 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt) WARN_ON_ONCE(in_irq()); lockdep_assert_irqs_enabled(); + lock_map_release(&bh_lock_map); + local_irq_save(flags); curcnt = __this_cpu_read(softirq_ctrl.cnt); @@ -275,6 +291,8 @@ 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