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 4EFE135968; Mon, 2 Jun 2025 14:06:09 +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=1748873169; cv=none; b=ueZ8fG1DsrIx+HJNPlb/1hQ5NO4dmkGCCEIhI9BMXrErHARcnxuBppP/iRTfafWY4VB6ENKBlgJPY50BtIV7mM4eUJEM3dcyCoyXv5Tsihkv6tpJ/fjR8rP+/BJsOrGqpcM+zWcS6Fni+4u/wSSq0f1+hixvfuzZfQF7IZviqAY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748873169; c=relaxed/simple; bh=DeWyc3fS8eR7tcPnewc0S4uPiqz9Yxi8PTRJaoB7h48=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k6F/zQ+7LhdSfqBsMKkmbWfMjz3LqOkELvaJxbUw3WPmU1OqjfaL/53G4DXqwWEl81BGk2+WwpOyb+uh02rCv0zYTwktaARFFXCTS+YWDj/E8Is5FMcopBnSInHgT96ryeSR7AEOmVFoX7vkJMlDqRnGqisZ1xdstnWHygFDNzw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NoV+m6ts; 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="NoV+m6ts" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5C68C4CEEB; Mon, 2 Jun 2025 14:06:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748873169; bh=DeWyc3fS8eR7tcPnewc0S4uPiqz9Yxi8PTRJaoB7h48=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NoV+m6tsyCNv7I7KcECzgvYuDneZ3hdOqiCgMdo7wl1MW/JSVSCAuRvSrdDhrZ0pm 3Z52ySGZJ3Xk7cULrNKXka2U8bHspmYLhvJ510drO3ZREkffPy4iTIowpJdhaRVtpm E9y5RatTpwXTuODYYY8jv8RCgSjFGxTWRfa/drUI= 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 6.6 060/444] lockdep: Fix wait context check on softirq for PREEMPT_RT Date: Mon, 2 Jun 2025 15:42:04 +0200 Message-ID: <20250602134343.362423653@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134340.906731340@linuxfoundation.org> References: <20250602134340.906731340@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 6.6-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 f24d80cf20bd3..d9e37f3fa1303 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -125,6 +125,18 @@ 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 * @@ -147,6 +159,8 @@ 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()) { @@ -210,6 +224,8 @@ 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); @@ -260,6 +276,8 @@ 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