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This is kind of last-minute, but Al Viro reported that the new FOP_DONTCACHE flag causes memory corruption due to use-after-free issues. This was triggered by commit974c5e6139("xfs: flag as supporting FOP_DONTCACHE"), but that is not the underlying bug - it is just the first user of the flag. Vlastimil Babka suspects the underlying problem stems from the folio_end_writeback() logic introduced in commitfb7d3bc414("mm/filemap: drop streaming/uncached pages when writeback completes"). The most straightforward fix would be to just revert the commit that exposed this, but Matthew Wilcox points out that other filesystems are also starting to enable the FOP_DONTCACHE logic, so this instead disables that bit globally for now. The fix will hopefully end up being trivial and we can just re-enable this logic after more testing, but until such a time we'll have to disable the new FOP_DONTCACHE flag. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/all/20250525083209.GS2023217@ZenIV/ Triggered-by:974c5e6139("xfs: flag as supporting FOP_DONTCACHE") Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>