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Fri, 27 Mar 2026 05:10:12 -0700 (PDT) From: Liew Rui Yan To: aethernet65535@gmail.com Cc: damon@lists.linux.dev, linux-mm@kvack.org, sj@kernel.org Subject: Re: [PATCH] mm/damon: validate addr_unit to be power of 2 Date: Fri, 27 Mar 2026 20:10:08 +0800 Message-ID: <20260327121009.38374-1-aethernet65535@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260327064517.68131-1-aethernet65535@gmail.com> References: <20260327064517.68131-1-aethernet65535@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: E41961C000E X-Stat-Signature: m56f56ybrpbs7oq8t1yjwh9wgdzsrmg5 X-Rspam-User: X-Rspamd-Server: rspam07 X-HE-Tag: 1774613413-561985 X-HE-Meta: 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 fO0GsND3 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi SeongJae, Regarding the kdamond termination, I have an idea: Should we avoid terminating kdamond just because of invalid parameters from user input (e.g., non-power-of-2 'min_region_sz' or 'addr_unit')? Since a terminated kdamond cannot be easily restarted currently (if it is not terminated by 'echo N > enabled'), we should probably try to reduce the probability of such unexpected exits caused by user input. I'm thinking of validating these parameters early in damon_commit_ctx(). If they are invalid, we could reset 'dst->maybe_corrupted' to 'false' and return -EINVAL. This way, since no actual modifications to 'dst' were made before the check, we can safely clear the 'maybe_corrupted' flag. User will then receive the error but kdamond should be able to keep running with its existing configuration instead of exiting. Does this approach make sense to you? Best regards, Rui Yan