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Howlett" , David Hildenbrand , Vlastimil Babka , Jann Horn Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mike Kaplinskiy , zhaozhengzhuo , "Lorenzo Stoakes (ARM)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1694; i=ljs@kernel.org; h=from:subject:message-id; bh=1c+ecH8uuNYp3IKgpKgpW07tV0l3TB+x9EGP2nGu9ZI=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLJm3f+3guFgy/vda766BCzVTUw7GKH9uXvt8upur6Cyi 5dCsln6O0pZGMS4GGTFFFmefxHfHyQSNq/zgr8bzBxWJpAhDFycAjARn02MDE+sf7/kKp7qcblV b4Xbju8bDJuZpTdbvmC5VdXh927RWyZGhgWzjs6/7Dd1qll3pdA3Ab7mlb/VBI5/lZzJ/XzL8i/ yO/gA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: xis93974dgrndww4ypk4jbea6utbip51 X-Rspamd-Queue-Id: 39AAC20009 X-HE-Tag: 1788534788-214389 X-HE-Meta: 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 PIY/XVEK CiFd0lN/Ev/Zmjhj0nCxUutOtG53/+ePmTn7V6FFq2WpB6pOxtgJ0txIyu2roJNwWHNc2qxo6oDEdeRFcIs1g5NuxBbcL9CHrWmyD7HUH+eb47exa5tuxBPyak3u1389N/Gqm7J9l029749RUb7g1F6IKFqxbnVzNVAIL18eyCbDYRju8kTuNurgmKICK02da8y5ZTdiTmJju+6V4t5aMsHPzHR0K+2d06CM/5kr4BGjToeHp4WI0SC5yaD1m6Du0oD8DRVAK19U/4S1YFbU06h5UQ7ZxZzRNJiRfUprPcSqBmjbC9nFZNNmaBw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Currently MADV_WILLNEED treats file-backed and pure anonymous mappings entirely separately - using POSIX_FADV_WILLNEED (equivalent of a readahead) for the former and a tree walk and swap in to swap cache for the latter. MAP_PRIVATE-file backed mappings straddle the two and currently get treated as if they were purely file-backed, meaning any swapped out private pages remain swapped out. Resolve the issue by explicitly checking for CoW'd MAP_PRIVATE-file backed mappings and performing both walks in this case. Since the logic checks for vma->anon_vma this means un-CoW'd MAP_PRIVATE-file backed mappings retain only the single file walk. Reported-by: Mike Kaplinskiy Closes: https://lore.kernel.org/all/CABeknB_S2XJSHFgnHdgnN0rjzHhH4oQJs_APq9fvxHztQ_pgiA@mail.gmail.com/ Signed-off-by: Lorenzo Stoakes (ARM) --- mm/madvise.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 73c2901b9adb..d0510dd49dde 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -297,10 +297,12 @@ static long madvise_willneed(struct madvise_behavior *madv_behavior) loff_t offset; #ifdef CONFIG_SWAP - if (!file) { + if (!file || (vma_is_cow_mapping(vma) && vma->anon_vma)) { walk_page_range_vma(vma, start, end, &swapin_walk_ops, vma); lru_add_drain(); /* Push any new pages onto the LRU now */ - return 0; + + if (!file) + return 0; } if (shmem_mapping(file->f_mapping)) { --- base-commit: e3b5239afe1b8f0194db7436b17c33e94c1988c4 change-id: 20260903-madv-will-need-map-private-125e3e2f70c7 Best regards, -- Lorenzo Stoakes (ARM)