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b=HkBDPEAQOXrI3Gg9U2MfFvNROwTs4e6c15CvvnNlWvp6OmG+UR75ihDJP59ErhLj7 R3isc3ieoRdKgC/5CYH2t2H35OXUcMtE3LKn+ohLi7NxMu92fyg0Qx0r/ishxE0Ya8 coOlaNJScPuqfe0nULrIHQPszOF4l1pCP02wjz0M= Date: Mon, 3 Nov 2025 18:56:08 -0800 From: Andrew Morton To: Youngjun Park Cc: linux-mm@kvack.org, Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Barry Song , Chris Li , stable@vger.kernel.org Subject: Re: [PATCH v2 1/1] mm: swap: remove duplicate nr_swap_pages decrement in get_swap_page_of_type() Message-Id: <20251103185608.84b2d685fe0ae4596307b878@linux-foundation.org> In-Reply-To: <20251102082456.79807-1-youngjun.park@lge.com> References: <20251102082456.79807-1-youngjun.park@lge.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9A0B4C0003 X-Stat-Signature: 3584fxnimz5ku7ecjgfwn71zp3ex1tp9 X-Rspam-User: X-HE-Tag: 1762224970-484506 X-HE-Meta: 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 gk/gwPL3 gVtzo4kCPF1y459WYTrJf+BM3FF35o3E52fy6BirzY3dJ1RWr2Jn8PyOW0AEp5NZuqu105EZ3HZFd7vFNsXMxjrWL1KSiQYAiTcdgK2iFVChBDGFyb4sBtXH69W0KpOU/2MIfk55Rc30rvlcWjw57WGUQ/l49DdNvpkz2d9WTwxOilmYTsD+XYJcINdoNr1AiEsVT63XeBDBkDJFNnR+Cnf72Na9Jy/6TI37Yi/IzCmY//qYL/tyqA4S07IHCEnn39+NFOMBnBoMrGKwIErXA4+rwhn3/S3017K+v+L2DSUnrofFYdJfs6z6s47HwgFXW0jw6tho/heo1V6m3S1Y8Oeg38EzDCb43izj8iqax1RxSjvflfquERTGR1w== 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 Sun, 2 Nov 2025 17:24:56 +0900 Youngjun Park wrote: > After commit 4f78252da887, nr_swap_pages is decremented in > swap_range_alloc(). Since cluster_alloc_swap_entry() calls > swap_range_alloc() internally, the decrement in get_swap_page_of_type() > causes double-decrementing. > > Remove the duplicate decrement. Can we please have a description of the userspace-visible runtime effects of the bug? > Fixes: 4f78252da887 ("mm: swap: move nr_swap_pages counter decrement from folio_alloc_swap() to swap_range_alloc()") > Cc: stable@vger.kernel.org # v6.17-rc1 Especially when proposing a backport. Thanks.