Description
In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix folio is still mapped when deleted Migration may be raced with fallocating hole. remove_inode_single_folio will unmap the folio if the folio is still mapped. However, it's called without folio lock. If the folio is migrated and the mapped pte has been converted to migration entry, folio_mapped() returns false, and won't unmap it. Due to extra refcount held by remove_inode_single_folio, migration fails, restores migration entry to normal pte, and the folio is mapped again. As a result, we triggered BUG in filemap_unaccount_folio. The log is as follows: BUG: Bad page cache in process hugetlb pfn:156c00 page: refcount:515 mapcount:0 mapping:0000000099fef6e1 index:0x0 pfn:0x156c00 head: order:9 mapcount:1 entire_mapcount:1 nr_pages_mapped:0 pincount:0 aops:hugetlbfs_aops ino:dcc dentry name(?):"my_hugepage_file" flags: 0x17ffffc00000c1(locked|waiters|head|node=0|zone=2|lastcpupid=0x1fffff) page_type: f4(hugetlb) page dumped because: still mapped when deleted CPU: 1 UID: 0 PID: 395 Comm: hugetlb Not tainted 6.17.0-rc5-00044-g7aac71907bde-dirty #484 NONE Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x4f/0x70 filemap_unaccount_folio+0xc4/0x1c0 __filemap_remove_folio+0x38/0x1c0 filemap_remove_folio+0x41/0xd0 remove_inode_hugepages+0x142/0x250 hugetlbfs_fallocate+0x471/0x5a0 vfs_fallocate+0x149/0x380 Hold folio lock before checking if the folio is mapped to avold race with migration.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
4aae8d1c051ea00b456da6811bc36d1f69de5445 to < bc1c9ce8aeff45318332035dbef9713fb9e982d7affected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < 91f548e920fbf8be3f285bfa3fa045ae017e836daffected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < 3e851448078f5b01f6264915df3cfef75e323a12affected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39affected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < c9c2a51f91aea70e89b496cac360cd795a2b3c26affected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < 910d7749346c4b0acdc6e4adfdc4a9984281a206affected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < 21ee79ce938127f88fe07e409c1817f477dbe7eaaffected4aae8d1c051ea00b456da6811bc36d1f69de5445 to < 7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7affected
Linux Linux
Default version status: affected
4.5affected0 to < 4.5unaffected5.4.300 to ≤ 5.4.*unaffected5.10.245 to ≤ 5.10.*unaffected5.15.194 to ≤ 5.15.*unaffected6.1.155 to ≤ 6.1.*unaffected6.6.109 to ≤ 6.6.*unaffected6.12.50 to ≤ 6.12.*unaffected6.16.10 to ≤ 6.16.*unaffected6.17 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/bc1c9ce8aeff45318332035dbef9713fb9e982d7 ↗
- https://git.kernel.org/stable/c/91f548e920fbf8be3f285bfa3fa045ae017e836d ↗
- https://git.kernel.org/stable/c/3e851448078f5b01f6264915df3cfef75e323a12 ↗
- https://git.kernel.org/stable/c/c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39 ↗
- https://git.kernel.org/stable/c/c9c2a51f91aea70e89b496cac360cd795a2b3c26 ↗
- https://git.kernel.org/stable/c/910d7749346c4b0acdc6e4adfdc4a9984281a206 ↗
- https://git.kernel.org/stable/c/21ee79ce938127f88fe07e409c1817f477dbe7ea ↗
- https://git.kernel.org/stable/c/7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7 ↗