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b=Gs27dfN21CiTt+PgfYYZx9Ka1+VQ/7yaR6M6MNvCNPmtci4NRpxu14XTw3/d6dYs8 HFT34C/cmGeM5zLSGKmCyKoNDf9qUp9MA5JfQzDpzty6SXc6Pdu34ueDpxBAk0eT4f 46AfpjGYpBbuTw+AH3bu+iq8U/gX+MTdrqaBZymNyp4B8elHWRedu65GC3IkBxXUD4 x4Jhfs24++lnYUzLNNgscL5bquYsiFBNDyzl4gtgVLtgwLgWxRHgM9ZTYQsTPgJwNZ C2GBpnYGRRkGc+3at035kkfF0rrq+nW+RJ3AluHwrcnMA2OB1QNompcuPBFMyCH6De dh9XD/40Jvrng== From: SeongJae Park To: Cc: SeongJae Park , "# 6 . 18 . x" , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 2/2] mm/damonn/lru_sort: handle ctx allocation failure Date: Wed, 27 May 2026 23:11:09 -0700 Message-ID: <20260528061110.2172-3-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260528061110.2172-1-sj@kernel.org> References: <20260528061110.2172-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 0B2BB100008 X-Stat-Signature: omjzt9qy1gwmwd4c67q9391jy7pq4m3y X-Rspam-User: X-HE-Tag: 1779948676-959013 X-HE-Meta: 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 udXGHsxU THA5r7XSHY2j3Z7vy1XS48nb13IJiXX/RkM/2TsSGSHUy/3HwBvOO4QelQhWI5j4rguaeUJH7S7aqe6N6rGvM8OWJI4z9k63QICUq9QA0givxPCpmCBKF91b0U+NOxzClDn4EBWbmdblTReL27VwyN25sLily6y9TQCqxHIPNPSbB10p++Y7SedTq6CS1bH9ECfpzJIEV02DgPTAEQox//2owHPCmS/94Pdsa2os4hazo4wqnQFWYQnLXb7fIUWThPpCn8HD+X4P35abL9BEoAWkO3Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: DAMON_LRU_SORT allocates the damon_ctx object for its kdamond in its init function. damon_lru_sort_enabled_store() wrongly assumes the allocation will always succeed once tried. If the damon_ctx allocation was failed, therefore, code execution reaches to damon_commit_ctx() while 'ctx' is NULL. As a result, it dereferences the NULL 'ctx' pointer. Avoid the NULL dereference by returning -ENOMEM if 'ctx' is NULL. Fixes: c4a8e662c839 ("mm/damon/lru_sort: use damon_initialized()") Cc: # 6.18.x Signed-off-by: SeongJae Park --- mm/damon/lru_sort.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c index eca88ed941b32..8298c6001fd09 100644 --- a/mm/damon/lru_sort.c +++ b/mm/damon/lru_sort.c @@ -476,6 +476,10 @@ static int damon_lru_sort_enabled_store(const char *val, if (!damon_initialized()) return 0; + /* damon_modules_new_paddr_ctx_target() in the init function failed. */ + if (!ctx) + return -ENOMEM; + return damon_lru_sort_turn(enabled); } -- 2.47.3