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Wed, 14 Jan 2026 13:02:43 +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 gRh7F/OTZ2l5cQAAD6G6ig (envelope-from ); Wed, 14 Jan 2026 13:02:43 +0000 Message-ID: <3d05c227-5a3b-44c7-8b1b-e7ac4a003b55@suse.cz> Date: Wed, 14 Jan 2026 14:02:43 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v2 01/20] mm/slab: add rcu_barrier() to kvfree_rcu_barrier_on_cache() Content-Language: en-US To: Harry Yoo Cc: Petr Tesarik , Christoph Lameter , David Rientjes , Roman Gushchin , Hao Li , Andrew Morton , Uladzislau Rezki , "Liam R. Howlett" , Suren Baghdasaryan , Sebastian Andrzej Siewior , Alexei Starovoitov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, bpf@vger.kernel.org, kasan-dev@googlegroups.com, kernel test robot , stable@vger.kernel.org References: <20260112-sheaves-for-all-v2-0-98225cfb50cf@suse.cz> <20260112-sheaves-for-all-v2-1-98225cfb50cf@suse.cz> <6e1f4acd-23f3-4a92-9212-65e11c9a7d1a@suse.cz> <342a2a8f-43ee-4eff-a062-6d325faa8899@suse.cz> 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-Rspam-User: X-Stat-Signature: mcs3hu65dq7r4g5bbe98zf8jt71awb1g X-Rspamd-Queue-Id: 9194A1C000B X-Rspamd-Server: rspam04 X-HE-Tag: 1768395765-363363 X-HE-Meta: U2FsdGVkX19LVrjs53MqdJ6oBRiQEe7dgG8W0Oyqkt8J1duWUF8QyZEdivxOXQvJ/kzHDIjzvZCK5EHN2MO1T1/UPjWZ6MUF562InhzYtAkxBLu77kyAe/NMAoZncaxra+phzV+8LpjIfPpzZQMRcD7RoNC6P0q0BF1WkV1mDbKiu40X0N34l4Kn/Es71zytFnLQv2st+i8/1/NcWqKfRqL0pV5pnif3Ed4pw3FYERQRHOMb+XvUpbG2lXQHnbQWIaPXLk89I1Ymq+8eg36K2tQvjWrFqyje6a4QQqlRqMmMiocxrh//NRa210LpilXxnpDUzK14psnFVpJArHU8Fhps4WEMrTJr5hdC88NDLdI24cQKKyXo1Esgm8dz+ejrv8tlqefUj0SfBRKG5ZrmPPiXEfBP6yE2wdVgrNq/UfqYuiWXqeN4g5TJ3a/svunc2aW3gHwMpmKEdiROo3MNac81J03zw2VGRlgUttUj9tmRUIajnM/itguDRHMp8Fz5QCE8UQUE1+2T7iW76wGvgzfK4VkuaioEsyEw9MlEPKhgnm088bgg1HFrXNuMWFhPF+yqdTWSlvDUMw2zhWmLrkD7aV7UPDOUPYib5T0Mi0E4ExCb6HHu0Ky1r3vxaWlHO3z8HLtq/AQtsMa8GdJJll6Qzom5XOVojNu9vgpym31XH1qrQgTxbUbFPi/0l73L6LxIJ8/bB1TNIDL3PmRnDu5amKabV9G2T5LRDmCj8ej0Fe5pZ8QuEJ+i01anAPcO2r6m4Ueo2BlNYLEdnArZ0Qz3evzwkKeOwieKG4A1LrOQ6+z5mgEDd5jGHAsvV8dqTILTE0sEGLMrZ7SkvmINGvRvD39kzwCbgWKJyDDJBZMVoGHPwW0DkV5ItPSHNW5pGQ9zBvAx0okqHRo3XaHCnTZL0anz5/gh3iKuTVHiFZV/iD4q2XUeVQ3nk7wsHej58XIB+uZH6A4j2Mo2k6F AA8gLAIV AMa3uB34zXHW0Jo1CEUjbHYjPEBnhselQcq493hY5NVgn7O9zkaBM0yqCryVe7J+7fFaOPc0dWxTtFtD47RhfUFhwrzQChEtIsWclC2sZwm1Yn7faAvpxfK0yo9TADfilt3DDa4bA9wUfliEeu9g1Vv10ApvDNRRQiB+Q0wuq0EBPfpOrl2O1F7D8P6fSxTsQN4PukOJpyfPwoNweV5euMyc5LyljKQZsKOaEWx55nYA3ejbBBJkEFnHep/XIpANnCu1w6vbxa25l0fltmDKW8MduNZjc97puLUgF5n/vmQlMLcwQ/QHyOCLbqtlg1wWvB/TJPcdqbjKlwcI= 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 1/14/26 12:14, Harry Yoo wrote: > For the record, an accurate analysis of the problem (as discussed > off-list): > > It turns out the object freed by sheaf_flush_unused() was in KASAN > percpu quarantine list (confirmed by dumping the list) by the time > __kmem_cache_shutdown() returns an error. > > Quarantined objects are supposed to be flushed by kasan_cache_shutdown(), > but things go wrong if the rcu callback (rcu_free_sheaf_nobarn()) is > processed after kasan_cache_shutdown() finishes. > > That's why rcu_barrier() in __kmem_cache_shutdown() didn't help, > because it's called after kasan_cache_shutdown(). > > Calling rcu_barrier() in kvfree_rcu_barrier_on_cache() guarantees > that it'll be added to the quarantine list before kasan_cache_shutdown() > is called. So it's a valid fix! Thanks a lot! Will incorporate to commit log. This being KASAN-only means further reducing the urgency.