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AJvYcCV9Jo5+mjtSy3Hgad9maTxmHbeeq0pEkWZ6NsGYWL7kS4WTjwF3B++SW/D2+jdEf42KPJCdsCKS1A==@kvack.org X-Gm-Message-State: AOJu0YwQqn1HeBIzNnaYi6ONZz2PH217JF+gDlrUgg5fCtW0R/niwLu1 fUIqOyzWRV0ZshW1tnAPs/bwyxLpKn97OulhhB7gzn2NEfxsAsxqyUUptaIekYkZCVAPPId3gwj X8emSjLPE2qsaF5H9mKXChPqYUYfdkq8cKVsKoT16YA== X-Gm-Gg: ASbGncspwkZ7XeRFyASXcOpOVHtFwqtpMZS6DiBVd+Xz5Tg1rmO3AN0x8oeu6qpjv6J 3TmUSQ96QbzGywugoEaNPKqANo9u2YtT1Ss6awukqRCUTzbfIa/jnB0D3lBL0IiusXwSa7xgM1C THSZC/b2ZL1idG88GCAdmJ522f3HSDJFQepz7EfJDigI2xSH3FVhSdo5K3vSf14GvxUmYGmtMIX zdr5MUCyrb5wWdkmpp7cyTKlgmp5W7TXp+Y5I9qg7Rb2hc6JDp9cW0wimty7sNQlbvH X-Google-Smtp-Source: AGHT+IEhUz7TtqzijSclhrRy4JTnMJo1kISMx7JAXBX1eo2l1LTuJlrlAmWzUxSKux9EXl5fjUpbnnV5TRFPrOucoPg= X-Received: by 2002:a05:6402:1456:b0:641:1cd6:fee9 with SMTP id 4fb4d7f45d1cf-64350e045f9mr15717357a12.1.1763491449779; Tue, 18 Nov 2025 10:44:09 -0800 (PST) MIME-Version: 1.0 References: <20251118181811.47336-1-pratyush@kernel.org> In-Reply-To: <20251118181811.47336-1-pratyush@kernel.org> From: Pasha Tatashin Date: Tue, 18 Nov 2025 13:43:32 -0500 X-Gm-Features: AWmQ_bmXkul2v5wS8yKC3okGvxsFI_LihBKfF6ZewAs9SUHa4l8gzAdSMkQR3AQ Message-ID: Subject: Re: [PATCH] kho: free already restored pages when kho_restore_vmalloc() fails To: Pratyush Yadav Cc: Andrew Morton , Alexander Graf , Mike Rapoport , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 59BC9A000D X-Stat-Signature: asn4s95xihrnbsks1jewe6ioann8wiim X-Rspam-User: X-HE-Tag: 1763491451-713306 X-HE-Meta: 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 9b1z4FCj aTs8cKVhABpwBoeAHAPdumQ4rKHlox1TZ7lcvjiAwBpH8yk1CEeAXRvNKECVlOdf57bezJUZHKbjm0TEo85CUhOCdUbBbEJnu0Up2i7+NOJV6shLxN5I9uLfDX+XL7hN6jRTbCuUJwmvWrFTCLBYdxraRNS5lCGkUfhnGAMEIns7HnZsVx9X+C8Ou3a+YGrWJmAFlBX/OgOMMCYyXwxao3n3x2Xuq19QP2AEEA3NjCA5IVbtsIqsIGDdr7JZkRvM7qGgQpHef6LTDhPw= 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: > When kho_restore_vmalloc() fails, it frees up the pages array, but not > the pages it contains. These are the pages that were successfully > restored using kho_restore_pages(). If the failure happens when > restoring the pages, the ones successfully restored are leaked. If the > failure happens when allocating the vm_area or when mapping the pages, > all the pages of the preserved vmalloc buffer are leaked. Hm, I am not sure if KHO should be responsible for freeing the restored pages. We don't know the content of those pages, and what they are used for. They could be used by a hypervisor or a device. Therefore, it may be better to keep them leaked, and let the caller decide what to do next: i.e., boot into a maintenance mode, crash the kernel, or allow the leak until the next reboot. Pasha