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U2FsdGVkX1/2bVv035oAS2hzPGeGBLTlDeAuXpXeuLodYUtNymBEWBeCSYD/PEWU5YhSnkW+iTHYAaPysJIZxR8pUxbskOAS88Dluv4cpI9FBH9aHK1MmS5mYu3Wgsd4KZvRzG/SSiTu5L+KpjCEJXL8cVxlHljbvOWUaq2cISJrWtjGw6g+tfWMySXpKlgjRDxX/k4UW+5USyQ3/5vt7CmbKQDUJotm5icZIbPhqDz74Zb0pBW70bQuplEB4lS3Ek69RqZjsZmZBdjT96mSkKG88J6nuh5sHeznRJiBZxvUsTMfbFVrCvQj8WNK8zsjLo1fv8kyVKir1Zag9nBIM5MZ5CuJ/vJAm1wUyPmb39BenP8Nx9tf6T7wmDipugXo9ZjWnquA/Y3bMFhtCKzFCUesrVYkUQfiB3o8AxPDmqcvhMRfEVJZzdzd6zdCzI2IXIF+tIF5kObHVWwH8DorWJeUbqSOtPFILc17NrDyj2EbUztU2EV9pT4DS8XyM2G7siseVDZfkh8HjhRYD5JWlUbjs/rkm6CfdXBT/CodqdI/gHlUyHQvoO1yTeqagi8rOfRMXHTrXSSLDynw9yaw66BfL+bKe9uV2btcpQNcycHoJzrKN2CkqierCfZRSvkKZgGZL+/Qe25yPsohbY34dcv2ovffjKMcl9T1CACw4pTsqP088cryB3/u5khz/jSfyK1ij26m8YdwWyOsdqufspkOqtf/MOjI9VBsIORLF9X/A+8SC1FfB2ZJ7sy96lYSDGT7sNweIrEwrWYwYJQqB4kNNku+KVzJcZvZ85GC233di9/EQUenCZ0loovsRy2YWSE7Xy/UhgOelV0jLwn9qD/NKhwugq/rdNYQJ7vkruOZYlkFKJfnbuebZFnTH8BD7zYEFSnSfRsnWFF25X76dEPSDRiMmMbyt4x4KdRD5PlcBpfNYgmPplOo5KZecmvLm9ac+0nXYMOUFjs6QNO 2B9Dijwo 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 26 Oct 2026, at 11:20, Lance Yang wrote: > collapse_file() can call page_cache_sync_readahead() while still holdin= g > source folios locked. If truncate holds mapping->invalidate_lock > exclusively and waits for one of those folios, readahead waits for > invalidate_lock and neither side can make progress. > > We need to release those folio locks before starting readahead. On a pa= ge > cache miss, roll back first, populate the collapse range, and retry onc= e. > Doing readahead after rollback avoids an extra pass when all folios are= > already present. If another miss occurs on retry, give up rather than k= eep > retrying while truncate or reclaim removes folios. > > Keep page_cache_sync_readahead() and wait for read I/O with > filemap_lock_folio(), releasing each folio before moving to the next. T= he > existing uptodate check during collapse still handles read errors. > > Shmem uses shmem_get_folio() for swapin and fallocated folios without > taking mapping->invalidate_lock, so it is unaffected. > > Reported-by: syzbot+16bf7cd0ebeb1de93aa5@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=3D16bf7cd0ebeb1de93aa5 > Fixes: 730633f0b7f9 ("mm: Protect operations adding pages to page cache= with invalidate_lock") > Cc: stable@vger.kernel.org > Signed-off-by: Lance Yang > --- > v3 -> v4: > - Move readahead after rollback and retry collapse once (per Pedro). > - Drop the preparation pass and its redundant uptodate check (per > Baolin and Pedro). Thanks! > - https://lore.kernel.org/all/20261016065920.4153-1-lance.yang@linux.d= ev/ > > mm/khugepaged.c | 44 +++++++++++++++++++++++++++++++++----------- > 1 file changed, 33 insertions(+), 11 deletions(-) > Acked-by: Zi Yan Best Regards, Yan, Zi