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Tue, 28 Jul 2026 21:52:57 -0700 (PDT) Received: from google.com ([2a00:79e0:2031:6:65c1:52a3:f6d3:37dc]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d022c2dfb1sm4915735ad.72.2026.07.28.21.52.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jul 2026 21:52:57 -0700 (PDT) Date: Wed, 29 Jul 2026 13:52:53 +0900 From: Sergey Senozhatsky To: Richard Chang Cc: Andrew Morton , Minchan Kim , Sergey Senozhatsky , Martin Liu , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/zsmalloc: fix release order of locks in zs_page_migrate() Message-ID: References: <20260728055333.421080-1-richardycc@google.com> <20260728111509.7662e385aea0b055d2066e1f@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: BD84B100005 X-Stat-Signature: sw3erkxhoqayy7o4kcs961yozo9b1xdo X-HE-Tag: 1785300778-185492 X-HE-Meta: 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 dDLE5FD6 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On (26/07/29 12:46), Richard Chang wrote: > On Wed, Jul 29, 2026 at 2:15 AM Andrew Morton wrote: > > > > Thanks. > > > > Does this actually fix a lockdep splat? If so, is a link available? > > > > No, this does not fix an active lockdep splat or a reported runtime deadlock. > It is just a code hygiene to release locks in LIFO order. Right, surprisingly enough lockdep was never unhappy with the original code (I run tests with CONFIG_PROVE_LOCKING=y.)