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Fri, 23 Jan 2026 16:56:00 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id QTPACyCoc2m5PQAAD6G6ig (envelope-from ); Fri, 23 Jan 2026 16:56:00 +0000 Message-ID: <1d360d08-aceb-4d0e-81ce-4544215603f6@suse.cz> Date: Fri, 23 Jan 2026 17:55:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RESEND v3 09/10] mm/vma: update vma_assert_locked() to use lockdep Content-Language: en-US To: Lorenzo Stoakes , Andrew Morton Cc: David Hildenbrand , "Liam R . Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shakeel Butt , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt References: From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Rspamd-Queue-Id: 53FD4100005 X-Stat-Signature: opmo6gcn5dqrcwspro1rp4p48uahm5dd X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1769187362-681946 X-HE-Meta: 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 YI1gMf+P YzaQ5VPAovudoB5JoEfg60+pSuAM0njmFcGEbz40sd3TPjIjaWVSdlM3Gs58wJ7yBojQbP79hJ7YwlHij5xq7m/6XbeQI52lviPa2NVKVIMoY0I6wdqu8qYtzfa8wbDwWFe2rGsefIYJnPC5doHxUZjMoGUbwf001H8KXhdiBg7IaJLvAtdWFV/SesmpLGCE9bqqZMVn59wZ/5DY8RIDKkFFLJzkfeKdSYgZPdO7T9qH9SA5mdXJMH3WkHvJV9NIGNGkitmI03tEDAg5JReg49p0MkekqeWlezbtnIpbPb0XL9j3IgJ04EBgcZO1jP63P6se46uvJ06fRoY6YgioJStFz16itlNv6wEkEtR1QPEANYwdDJt4gnrBJ+wKgSseMB5Z31a8vjZrALBfnlrl4GailtQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/22/26 14:02, Lorenzo Stoakes wrote: > +/** > + * vma_assert_locked() - assert that @vma holds either a VMA read or a VMA write > + * lock and is not detached. > + * @vma: The VMA to assert. > + */ > static inline void vma_assert_locked(struct vm_area_struct *vma) > { > - unsigned int mm_lock_seq; > + unsigned int refs; > > /* > * See the comment describing the vm_area_struct->vm_refcnt field for > * details of possible refcnt values. > */ > - VM_BUG_ON_VMA(refcount_read(&vma->vm_refcnt) <= 1 && > - !__is_vma_write_locked(vma, &mm_lock_seq), vma); > + > + /* > + * If read-locked or currently excluding readers, then the VMA is > + * locked. > + */ > +#ifdef CONFIG_LOCKDEP > + if (lock_is_held(&vma->vmlock_dep_map)) > + return; > +#endif > + > + refs = refcount_read(&vma->vm_refcnt); > + > + /* > + * In this case we're either read-locked, write-locked with temporary > + * readers, or in the midst of excluding readers, all of which means > + * we're locked. > + */ > + if (refs > 1) > + return; > + > + /* It is a bug for the VMA to be detached here. */ > + VM_BUG_ON_VMA(!refs, vma); > + Yeah previously this function was all VM_BUG_ON() but since that's now frowned upon, can we not do it anymore? Seem we do have VM_WARN_ON_ONCE_VMA(). > + /* > + * OK, the VMA has a reference count of 1 which means it is either > + * unlocked and attached or write-locked, so assert that it is > + * write-locked. > + */ > + vma_assert_write_locked(vma); > } > > static inline bool vma_is_attached(struct vm_area_struct *vma) > -- > 2.52.0