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dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-681ff7000002311f-9d-682319f12074 From: Byungchul Park To: linux-kernel@vger.kernel.org Cc: kernel_team@skhynix.com, torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, harry.yoo@oracle.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com, max.byungchul.park@gmail.com, boqun.feng@gmail.com, longman@redhat.com, yskelg@gmail.com, yunseong.kim@ericsson.com, yeoreum.yun@arm.com, netdev@vger.kernel.org, matthew.brost@intel.com, her0gyugyu@gmail.com Subject: [PATCH v15 30/43] cpu/hotplug: use a weaker annotation in AP thread Date: Tue, 13 May 2025 19:07:17 +0900 Message-Id: <20250513100730.12664-31-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20250513100730.12664-1-byungchul@sk.com> References: <20250513100730.12664-1-byungchul@sk.com> X-Brightmail-Tracker: H4sIAAAAAAAAAz2Ta0yTZxTHfZ731lZLXjvnXumyzSrRYMaGQ3eWqDEmuGeJCyZ+8JYozXi1 zbil3ISEBLQQLZcwDKJSakFXESrUUi9zlFQMHZeMgWJBhlDIIhJBMrDNCsjWovPLyT/nf/6/ 8+UcCaXoYMIl2uR0UZesTlSxMlo2varm87/XbdB82Xn/G/C9PkuDscnKQm9jAwKrIx/DZPu3 MOCfQrDw+x8UVFb0IqgZe0aBwz2CwFl3moXHf4VBv2+Ghc6KIhbOXG1ioe/lIobhC+UYGuzf w6jlOQ3dZbUYKidZqKo8g4PlBYaApZ4DS14EjNdd5mBxLBo6RzwMOIe2wCXTMAstzk4a3PfG MTy+b2RhxPovA93uDhr8pUro/amEgZuvall46bdQYPHNcPDIZcbgNq8Fmz4ILJxbYuC3EheG wmu3MPQ//RVB61kvBrvVw8JD3xSGZnsFBfPX2xGMl05zUFAc4KAqvxRBUcEFGvTD22Dhn+Dm 6tfRkH/FRsPNNx60eyexmqyIPJyaoYi+OYvM+56wxOk306SrViC/XH7GEX3rEEfM9gzSXBdJ rrZMYlIz62OIvf4cS+yz5RwxTPdj8qqnh9v/8RHZjgQxUZsp6r7YFS/TtFsWcKpXeurukwmU hxY5A5JKBD5GsDm87/X86A06pFl+kzA4GKBCeg3/mdBc8pwxIJmE4j0rhYHqpyhkfMDvE2r+ dC0HaD5CmFhawiEt57cLrpHBd9BPhQabaxkkDfbfXO9Znlfw24QycwMdggp8lVQoLLYwbwPr hAd1g3QZkpvRinqk0CZnJqm1iTFRmuxk7amoH1KS7Ch4X5bcxaP30GzvgTbES5Bqlbxjcr1G wagz07KT2pAgoVRr5Pl3gy15gjo7R9SlHNdlJIppbUgpoVUfybf6sxIU/El1uvijKKaKuv9d LJGG56HTzpKu7+Juz7U+issZW7leEVZw4I43Z3t1YMG0Om7fZseOk/rajTvxXsPhiy5b7PmA ++C8Sbn10IukzaMTnxTHH7x02HPCEfNVuPxD6R5j1INhU5NyLUrpOzZU1HLFEGHM2pvRyqbH 5ga/JTfrovJrHe/MW3Gtyxg210givXz4zyo6TaOOjqR0aer/AIXIDF5bAwAA X-Brightmail-Tracker: H4sIAAAAAAAAAzWSfUzMcRzHfb+/p7vj9Ntp+smMztN2JjLZx8PMs988zR8e5tmtfutOV7ir VMZKVyNqadJEuoqT6yiXKXR2SsdlUnoQ6lRMokS6pgdxNf757LX3+/N5v//5iAiZifIWqUPD BG2oUiOnJaRky9K4uT8mTVfNTyn0AVfvaRKuFJhpqL6dj8B8NxZDR8V6eN3XiWDwxUsC0tOq EWS3NhNw1+5EYM07RUPtx/FQ5+qmwZF2loa43AIaar4OYWi6mIoh37IZ3hs/kfA8JQdDegcN l9PjsHt8xtBvNDFgjJkJbXkZDAy1+oHD2UBBeaaDAuvbOXDpahMNpVYHCfaSNgy1D67Q4DT/ oeC5/RkJfcmTofp8EgW3vuXQ8LXPSIDR1c3AK5sBg90wEQr17tSEn8MUPE2yYUi4dgdD3ZuH CB6dbsFgMTfQUO7qxFBkSSNg4EYFgrbkLgbiz/UzcDk2GcHZ+Isk6Jv8YfCXuzmz1w9iswpJ uPW7Aa1YzpuvmhFf3tlN8PqiY/yAq57mrX0Gkq/M4fj7Gc0Mr3/0luENlnC+KE/B55Z2YD67 x0XxFtMZmrf0pDJ8Ylcd5r9VVTFbp+yWLAsUNOoIQTtv+UGJqsI4iI+0iCOL69tRDBpiEpFY xLELuYH3N8kRptnZXGNjPzHCnuw0rijpE5WIJCKCbRjLvc58g0aMCewmLvudbfSAZGdy7cPD eISl7CLO5mz8FzqVyy+0jQaJ3frvG1Wj+zLWn0sx5JMpSGJAY0zIUx0aEaJUa/x9dcGqqFB1 pG/A4RALcn+Q8cTQ+RLUW7u+DLEiJB8nfdbho5JRyghdVEgZ4kSE3FMaW+yWpIHKqGhBe/iA Nlwj6MrQZBEp95Ju2CkclLFByjAhWBCOCNr/LhaJvWPQ5ubraw9F/9izfUnW3ujpVUFjepzF S+ru+XadCzDfNodE7tHPsETvTTCt+XJyX9YL264Webi81a/2+MrVXWOffK9X+/zxeHD02mLp QodGfCGsJmpWZYnPu/1ewR5ckv3DyeOPL2x4GjSpPSM1dUfCtrgzioJS7wXW4XWVOxWrFsXH bNmolpM6ldJPQWh1yr8J1dEwPQMAAA== X-CFilter-Loop: Reflected Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" cb92173d1f0 ("locking/lockdep, cpu/hotplug: Annotate AP thread") was introduced to make lockdep_assert_cpus_held() work in AP thread. However, the annotation is too strong for that purpose. We don't have to use more than try lock annotation for that. rwsem_acquire() implies: 1. might be a waiter on contention of the lock. 2. enter to the critical section of the lock. All we need in here is to act 2, not 1. So trylock version of annotation is sufficient for that purpose. Now that dept partially relies on lockdep annotaions, dept interpets rwsem_acquire() as a potential wait and might report a deadlock by the wait. Replace it with trylock version of annotation. Signed-off-by: Byungchul Park --- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index b08bb34b1718..3eecd0a7b5b3 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -537,7 +537,7 @@ int lockdep_is_cpus_held(void) =20 static void lockdep_acquire_cpus_lock(void) { - rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); + rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 1, _THIS_IP_); } =20 static void lockdep_release_cpus_lock(void) --=20 2.17.1