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[66.111.4.227]) by smtp.gmail.com with ESMTPSA id l11sm1402485ilo.77.2021.06.18.10.01.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Jun 2021 10:01:46 -0700 (PDT) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailauth.nyi.internal (Postfix) with ESMTP id C290A27C005A; Fri, 18 Jun 2021 13:01:45 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Fri, 18 Jun 2021 13:01:45 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrfeeffedguddtgecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpefhvffufffkofgjfhgggfestdekredtredttdenucfhrhhomhepuehoqhhu nhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrihhlrdgtohhmqeenucggtffrrg htthgvrhhnpeehvdevteefgfeiudettdefvedvvdelkeejueffffelgeeuhffhjeetkeei ueeuleenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpe gsohhquhhnodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhithihqdeiledvgeehtdei gedqudejjeekheehhedvqdgsohhquhhnrdhfvghngheppehgmhgrihhlrdgtohhmsehfih igmhgvrdhnrghmvg X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 18 Jun 2021 13:01:45 -0400 (EDT) From: Boqun Feng To: Peter Zijlstra Cc: Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , linux-kernel@vger.kernel.org, Johannes Berg Subject: [PATCH 4/4] locking/selftests: Add a selftest for check_irq_usage() Date: Sat, 19 Jun 2021 01:01:10 +0800 Message-Id: <20210618170110.3699115-5-boqun.feng@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210618170110.3699115-1-boqun.feng@gmail.com> References: <20210618170110.3699115-1-boqun.feng@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Johannes Berg reported a lockdep problem which could be reproduced by the special test case introduced in this patch, so add it. Signed-off-by: Boqun Feng --- lib/locking-selftest.c | 65 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 2d85abac1744..5c50b0910396 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -53,6 +53,7 @@ __setup("debug_locks_verbose=", setup_debug_locks_verbose); #define LOCKTYPE_WW 0x10 #define LOCKTYPE_RTMUTEX 0x20 #define LOCKTYPE_LL 0x40 +#define LOCKTYPE_SPECIAL 0x80 static struct ww_acquire_ctx t, t2; static struct ww_mutex o, o2, o3; @@ -2744,6 +2745,66 @@ static void local_lock_tests(void) pr_cont("\n"); } +static void hardirq_deadlock_softirq_not_deadlock(void) +{ + /* mutex_A is hardirq-unsafe and softirq-unsafe */ + /* mutex_A -> lock_C */ + mutex_lock(&mutex_A); + HARDIRQ_DISABLE(); + spin_lock(&lock_C); + spin_unlock(&lock_C); + HARDIRQ_ENABLE(); + mutex_unlock(&mutex_A); + + /* lock_A is hardirq-safe */ + HARDIRQ_ENTER(); + spin_lock(&lock_A); + spin_unlock(&lock_A); + HARDIRQ_EXIT(); + + /* lock_A -> lock_B */ + HARDIRQ_DISABLE(); + spin_lock(&lock_A); + spin_lock(&lock_B); + spin_unlock(&lock_B); + spin_unlock(&lock_A); + HARDIRQ_ENABLE(); + + /* lock_B -> lock_C */ + HARDIRQ_DISABLE(); + spin_lock(&lock_B); + spin_lock(&lock_C); + spin_unlock(&lock_C); + spin_unlock(&lock_B); + HARDIRQ_ENABLE(); + + /* lock_D is softirq-safe */ + SOFTIRQ_ENTER(); + spin_lock(&lock_D); + spin_unlock(&lock_D); + SOFTIRQ_EXIT(); + + /* And lock_D is hardirq-unsafe */ + SOFTIRQ_DISABLE(); + spin_lock(&lock_D); + spin_unlock(&lock_D); + SOFTIRQ_ENABLE(); + + /* + * mutex_A -> lock_C -> lock_D is softirq-unsafe -> softirq-safe, not + * deadlock. + * + * lock_A -> lock_B -> lock_C -> lock_D is hardirq-safe -> + * hardirq-unsafe, deadlock. + */ + HARDIRQ_DISABLE(); + spin_lock(&lock_C); + spin_lock(&lock_D); + spin_unlock(&lock_D); + spin_unlock(&lock_C); + HARDIRQ_ENABLE(); +} + void locking_selftest(void) { /* @@ -2872,6 +2933,10 @@ void locking_selftest(void) local_lock_tests(); + print_testname("hardirq_unsafe_softirq_safe"); + dotest(hardirq_deadlock_softirq_not_deadlock, FAILURE, LOCKTYPE_SPECIAL); + pr_cont("\n"); + if (unexpected_testcase_failures) { printk("-----------------------------------------------------------------\n"); debug_locks = 0; -- 2.30.2