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b=jBzEjqFJ1M2qH9kDhXArAiBA52bw9oPlUpcxKq2q+U/lWvaDw3J8QC8jOFGh/G/lf KfdobvROy4Jj/QIhPTA1+wq8v2MxUx8UyMZS6zYFcxoLUzvEJrV800sceWdXm1rHxT JrJ1siN49rXwG/EHOhrNymsDa6vV9ExazJceml+wMWRIKeYha4V7yZI61dItQbTA4w rUz5HMe401+QZvGMqjIDijYrgVYdLUVF1q6PY81MiaJlC+DK7wqsz2/PUPLVjxqH3E kpo0I1RnHUnYlVgtOsfaadZJVGoGVS0vlmGy2rNsekQRKmMC4/yLa7U4mMrS/ORDIE T+xNsYlufIonA== From: SeongJae Park To: Liew Rui Yan Cc: SeongJae Park , yanquanmin1@huawei.com, damon@lists.linux.dev, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [PATCH v3 2/2] mm/damon/reclaim: validate min_region_size to be power of 2 Date: Fri, 3 Apr 2026 09:20:50 -0700 Message-ID: <20260403162050.65121-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260403052837.58063-3-aethernet65535@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: xiejmgp6fp5fmt54oty57zr5emro7n9h X-Rspamd-Queue-Id: 1D837100008 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1775233252-814170 X-HE-Meta: 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 H/EoaXue xlA0nwIJ/NVWoE4axNar52xJKp/sc5I86H3w9MAC+70asrvUQ4Gng9pbiUe6Y8NjxXAgaZIvz0V6zCTSRaFebf0Df4OsHvaScusp/ipGtPt0hsELcJV/2Q4wvY+aar8i+o/0xQ5yWkAphYlcsXva0Pb6S7UOzUBms2oOyBCr1qj5P4nP/BCTDQ5cXPhDZUuOgmso/ixwKgGEz5F4+01mSOvtiMqfHEwr3loBs8SRoBoLJdp7PZoGlcKh0+otSGSIuoqj6dNxmZg8NPaQpM0rVOZE198P93RXV9zFb7dK1CEdJJ0s= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 3 Apr 2026 13:23:50 +0800 Liew Rui Yan wrote: > The damon_commit_ctx() checks if 'min_region_sz' is a power-of-2. > However, if an invalid input is provided via the DAMON_RECLAIM interface, > the validation failure occurs too late, causing kdamond to terminate > unexpectedly. > > To reproduce: > 1. Enable DAMON_RECLAIM. > 2. Set an invalid 'addr_unit' (e.g., addr_unit=3) so that > 'min_region_sz = DAMON_MIN_REGION_SZ / addr_unit' becomes > non-power-of-2. > 3. Commit parameters, and observe kdamond termination. > > This patch adds an early check in damon_reclaim_apply_parameters() to > validate 'min_region_sz' and return -EINVAL immediately if it is not a > power-of-2, preventing unexpected kdamond termination. > > Fixes: 7db551fcfb2a ("mm/damon/reclaim: support addr_unit for DAMON_RECLAIM") > Cc: # 6.18.x I'm not very sure if this deserves Cc-ing stable@. I posted more details on my reply to the first patch of this series. Let's discuss further on the thread. I will skip reviewing this patch until the discussion on the thread is done. Thanks, SJ [...]