kernel/git/stable/linux.git/fs/f2fs, branch linux-rolling-stable

f2fs: read COW data with the original inode during atomic write

2026-07-04T11:45:05+00:00

commit a41075acde0124d2f8a5f563068a5d63e8ffd57b upstream. When updating an atomic-write file, f2fs_write_begin() may read the previously written data back from the COW inode: prepare_atomic_write_begin() locates the block in the COW inode and sets use_cow, and the read bio is then built with the COW inode: f2fs_submit_page_read(use_cow ? F2FS_I(inode)->cow_inode : inode, ...); and f2fs_grab_read_bio() decides whether to schedule fs-layer decryption (STEP_DECRYPT) for the bio based on that inode via fscrypt_inode_uses_fs_layer_crypto(). However, the folio being filled belongs to the original inode (folio->mapping->host == inode), and the data stored in the COW block was encrypted (or left as plaintext) using the original inode's context, not the COW inode's -- see f2fs_encrypt_one_page(), which keys off fio->page->mapping->host. fscrypt_decrypt_pagecache_blocks() likewise operates on folio->mapping->host. The COW inode is created as a tmpfile in the parent directory and inherits its encryption policy from there. With test_dummy_encryption the newly created COW inode gets the dummy policy and becomes encrypted, while a pre-existing regular file -- created before the policy applied, e.g. already present in the on-disk image -- stays unencrypted. The read path then sets STEP_DECRYPT based on the encrypted COW inode and calls fscrypt_decrypt_pagecache_blocks() on a folio whose host (the unencrypted original inode) has a NULL ->i_crypt_info, dereferencing it: Oops: general protection fault, probably for non-canonical address ... KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:fscrypt_decrypt_pagecache_blocks+0xa0/0x310 Workqueue: f2fs_post_read_wq f2fs_post_read_work Call Trace: fscrypt_decrypt_bio+0x1eb/0x340 f2fs_post_read_work+0xba/0x140 process_one_work+0x91c/0x1a40 worker_thread+0x677/0xe90 kthread+0x2bc/0x3a0 The COW inode is only needed to locate the on-disk block, and that block address is already resolved into @blkaddr by prepare_atomic_write_begin() via __find_data_block(cow_inode, ...); f2fs_submit_page_read() then reads from that physical @blkaddr directly, so the inode argument only selects the post-read crypto context, not which block is fetched. Reading with @inode therefore returns the same (latest, not-yet-committed) COW data, while making both the fs-layer decryption decision and the inline crypto path use the correct (original inode's) key. With the COW inode no longer used at the read site, the use_cow flag has no remaining consumer; drop it from f2fs_write_begin() and prepare_atomic_write_begin(). Fixes: 591fc34e1f98 ("f2fs: use cow inode data when updating atomic write") Cc: stable@vger.kernel.org Signed-off-by: Mikhail Lobanov Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: keep atomic write retry from zeroing original data

2026-07-04T11:45:05+00:00

commit 6d874b65aadce56ac78f76129dbcfc2599b638f8 upstream. A partial atomic write reserves a block in the COW inode before reading the original data page for the untouched bytes in that page. If that read fails, write_begin returns an error but leaves the COW inode entry as NEW_ADDR. A retry of the same partial write then finds the COW entry, treats it as existing COW data, and f2fs_write_begin() zeroes the whole folio because blkaddr is NEW_ADDR. If the retry is committed, the bytes outside the retried write range are committed as zeroes instead of preserving the original file contents. Only use the COW inode as the read source when it already has a real data block. If the COW entry is still NEW_ADDR, treat it as a reservation to reuse: keep reading the old data from the original inode and avoid reserving or accounting the same atomic block again. Cc: stable@kernel.org Fixes: 3db1de0e582c ("f2fs: change the current atomic write way") Signed-off-by: Wenjie Qi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()

2026-07-04T11:45:05+00:00

commit 1f70ddb28a3c71df124da5fa4040c808116d6bb9 upstream. When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does not reset the length of the largest extent to 0 and update the inode folio. Since modifications to the extent tree are disallowed afterward, the cached largest extent may become stale. This can trigger the following error in xfstests generic/388: F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix In the f2fs_drop_inode path, __destroy_extent_node() does not need to guarantee that et->node_cnt is 0, because concurrency with writeback is expected in this path, and writeback may update the extent cache. This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback"), and remove the unnecessary zero check of et->node_cnt. Fixes: ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback") Cc: stable@vger.kernel.org Reported-by: Chao Yu Suggested-by: Chao Yu Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

Revert "f2fs: remove non-uptodate folio from the page cache in move_data_block"

2026-07-04T11:45:05+00:00

commit ccaba785821970f422c47770331c7e3271763f17 upstream. This reverts commit 9609dd704725a40cd63d915f2ab6c44248a44598. The kernel panics are keeping to be reported especially when the f2fs partition get almost full. By investigation, we find that the reason is one f2fs page got freed to buddy without being deleted from LRU and the root cause is the race happened in [2] which is enrolled by this commit. There are 3 race processes in this scenario, please find below for their main activities. The changed code in move_data_block() lets the GC path evict the tail-end folio from the page cache through folio_end_dropbehind(). Once folio_unmap_invalidate() removes the folio from mapping->i_pages, the page-cache references for all pages in the folio are dropped. The folio is then kept alive only by temporary external references, which allows a later split to operate on a folio whose subpages are no longer protected by page-cache references. After the page-cache references are gone, split_folio_to_order() can split the big folio into individual pages and put the resulting subpages back on the LRU. For tail pages beyond EOF, split removes them from the page cache and drops their page-cache references. A tail page can then remain on the LRU with PG_lru set while holding only the split caller's temporary reference. When free_folio_and_swap_cache() drops that final reference, the page enters the final folio_put() release path. In parallel, folio_isolate_lru() can observe the same tail page with a non-zero refcount and PG_lru set. It clears PG_lru before taking its own reference. If this races with the final folio_put() from the split path, __folio_put() sees PG_lru already cleared and skips lruvec_del_folio(). The page is then freed back to the allocator while its lru links are still present in the LRU list. A later LRU operation on a neighboring page detects the stale link and reports list corruption. [1] [ 22.486082] list_del corruption. next->prev should be fffffffec10e0ac8, but was dead000000000122. (next=fffffffec10e0a88) [ 22.486130] ------------[ cut here ]------------ [ 22.486134] kernel BUG at lib/list_debug.c:67! [ 22.486141] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 22.488502] Tainted: [W]=WARN, [O]=OOT_MODULE [ 22.488506] Hardware name: Spreadtrum UMS9230 1H10 SoC (DT) [ 22.488511] pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 22.488517] pc : __list_del_entry_valid_or_report+0x14c/0x154 [ 22.488531] lr : __list_del_entry_valid_or_report+0x14c/0x154 [ 22.488539] sp : ffffffc08006b830 [ 22.488542] x29: ffffffc08006b868 x28: 0000000000003020 x27: 0000000000000000 [ 22.488553] x26: 0000000000000000 x25: 0000000000000004 x24: fffffffec10e0ac0 [ 22.488564] x23: 00000000000000e8 x22: 0000000000000024 x21: dead000000000122 [ 22.488574] x20: fffffffec10e0a88 x19: fffffffec10e0ac8 x18: ffffffc080061060 [ 22.488585] x17: 20747562202c3863 x16: 6130653031636566 x15: 0000000000000058 [ 22.488595] x14: 0000000000000004 x13: ffffff80f91e0000 x12: 0000000000000003 [ 22.488605] x11: 0000000000000003 x10: 0000000000000001 x9 : ffe85721f0e25f00 [ 22.488615] x8 : ffe85721f0e25f00 x7 : 0000000000000000 x6 : 6c65645f7473696c [ 22.488625] x5 : ffffffed39b23026 x4 : 0000000000000000 x3 : 0000000000000010 [ 22.488636] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 000000000000006d [ 22.488647] Call trace: [ 22.488651] __list_del_entry_valid_or_report+0x14c/0x154 (P) [ 22.488661] __folio_put+0x2bc/0x434 [ 22.488670] folio_put+0x28/0x58 [ 22.488678] do_garbage_collect+0x1a34/0x2584 [ 22.488689] f2fs_gc+0x230/0x9b4 [ 22.488697] f2fs_fallocate+0xb90/0xdf4 [ 22.488706] vfs_fallocate+0x1b4/0x2bc [ 22.488716] __arm64_sys_fallocate+0x44/0x78 [ 22.488725] invoke_syscall+0x58/0xe4 [ 22.488732] do_el0_svc+0x48/0xdc [ 22.488739] el0_svc+0x3c/0x98 [ 22.488747] el0t_64_sync_handler+0x20/0x130 [ 22.488754] el0t_64_sync+0x1c4/0x1c8 [2] CPU0 (f2fs GC) CPU1 (split_folio_to_order) CPU2 (folio_isolate_lru) F: pagecache refs = n F: extra refs = GC + split F: PG_lru set move_data_block() folio = f2fs_grab_cache_folio(F) ... __folio_set_dropbehind(F) folio_unlock(F) folio_end_dropbehind(F) folio_unmap_invalidate(F) __filemap_remove_folio(F) folio_put_refs(F, n) folio_put(F) split_folio_to_order(F) folio_ref_freeze(F, 1) ... lru_add_split_folio(T) list_add_tail(&T->lru, &F->lru) folio_set_lru(T) __filemap_remove_folio(T) folio_put_refs(T, 1) /* T refcount == 1, PageLRU set */ folio_isolate_lru(T) folio_test_clear_lru(T) free_folio_and_swap_cache(T) folio_put(T) /* refcount: 1 -> 0 */ __folio_put(T) __page_cache_release(T) folio_test_lru(T) == false /* skip lruvec_del_folio(T) */ free_frozen_pages(T) folio_get(T) lruvec_del_folio(T) later: list_del(adjacent->lru) next == &T->lru next->prev == LIST_POISON / PCP freelist BUG Cc: stable@vger.kernel.org Fixes: 9609dd704725 ("f2fs: remove non-uptodate folio from the page cache in move_data_block") Signed-off-by: Zhaoyang Huang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: validate ACL entry sizes in f2fs_acl_from_disk()

2026-07-04T11:45:05+00:00

commit c4810ada31e80cbe4011467c4f3b1e93f94134f3 upstream. f2fs_acl_count() only validates the aggregate ACL xattr length. A malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk() then reads entry->e_id before verifying that a full entry fits. Require a short entry before reading e_tag and e_perm, and require a full entry before reading e_id for ACL_USER and ACL_GROUP. Return -EFSCORRUPTED from these new truncated-entry checks, while keeping the pre-existing -EINVAL paths unchanged. Validation reproduced this kernel report: KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0 RIP: 0033:0x7f4b835ea7aa The buggy address belongs to the object at ffff888114589960 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes to the right of allocated 8-byte region [ffff888114589960, ffff888114589968) Read of size 4 Call trace: dump_stack_lvl+0x66/0xa0 (?:?) print_report+0xce/0x630 (?:?) __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169) srso_alias_return_thunk+0x5/0xfbef5 (?:?) __virt_addr_valid+0x224/0x430 (?:?) kasan_report+0xe0/0x110 (?:?) __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169) __get_acl+0x281/0x380 (?:?) vfs_get_acl+0x10b/0x190 (?:?) do_get_acl+0x2a/0x410 (?:?) do_get_acl+0x9/0x410 (?:?) do_getxattr+0xe8/0x260 (?:?) filename_getxattr+0xd1/0x140 (?:?) do_getname+0x2d/0x2d0 (?:?) path_getxattrat+0x16c/0x200 (?:?) lock_release+0xc8/0x290 (?:?) cgroup_update_frozen+0x9d/0x320 (?:?) lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?) trace_hardirqs_on+0x1a/0x170 (?:?) _raw_spin_unlock_irq+0x28/0x50 (?:?) do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?) Cc: stable@kernel.org Fixes: af48b85b8cd3 ("f2fs: add xattr and acl functionalities") Assisted-by: Codex:gpt-5.5 Signed-off-by: Zhang Cen Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: bound i_inline_xattr_size for non-inline-xattr inodes

2026-07-04T11:45:05+00:00

commit 378acf3cf19b6af6cba55e8dd1154c4e1504bae8 upstream. When the flexible_inline_xattr feature is enabled, do_read_inode() loads the on-disk i_inline_xattr_size unconditionally: if (f2fs_sb_has_flexible_inline_xattr(sbi)) fi->i_inline_xattr_size = le16_to_cpu(ri->i_inline_xattr_size); but sanity_check_inode() only range-checks it when the inode also has the FI_INLINE_XATTR flag set. An inode that carries an inline dentry or inline data but not FI_INLINE_XATTR -- the normal layout for an inline directory -- therefore keeps a fully attacker-controlled i_inline_xattr_size from a crafted image. get_inline_xattr_addrs() returns that value with no flag gating, so it feeds the inode geometry: MAX_INLINE_DATA() = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1) NR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...) addrs_per_page() = CUR_ADDRS_PER_INODE - i_inline_xattr_size A large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY() negative, so make_dentry_ptr_inline() sets d->max (int) to a negative value. The inline directory walk then compares an unsigned long bit_pos against that negative d->max, which is promoted to a huge unsigned bound, and reads far past the inline area: while (bit_pos < d->max) /* fs/f2fs/dir.c */ ... test_bit_le(bit_pos, d->bitmap) / d->dentry[bit_pos] ... Mounting a crafted image and reading such a directory triggers an out-of-bounds read in f2fs_fill_dentries(); the same underflow also corrupts ADDRS_PER_INODE for regular files. Validate i_inline_xattr_size against MAX_INLINE_XATTR_SIZE whenever the flexible_inline_xattr feature is enabled -- i.e. whenever the value is loaded from disk and consumed -- and keep the lower MIN_INLINE_XATTR_SIZE bound gated on inodes that actually carry an inline xattr, so legitimate inodes with i_inline_xattr_size == 0 are still accepted. Cc: stable@vger.kernel.org Fixes: 6afc662e68b5 ("f2fs: support flexible inline xattr size") Signed-off-by: Bryam Vargas Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: fix to round down start offset of fallocate for pin file

2026-07-04T11:45:05+00:00

commit 4275b59673eb60b02eec3997816c83f1f4b909c4 upstream. Currently, the length of fallocate for pin file is section-aligned to keep allocated sections from being selected as victims of GC. However, for the case that the start offset of fallocate is not aligned in section, the allocated sections can't be fully utilized. It's because a new section is allocated by f2fs_allocate_pinning_section() after using blks_per_sec blocks regardless of the start offset. As a result, several unexpected dirty segments may be created, including blocks assigned to the pinned file. To address this issue, let's round down the start offset of fallocate to the length of section. The reproducing scenario is as below chunk=$(((2<<20)+4096)) # 2MB + 4KB touch test f2fs_io pinfile set test f2fs_io fallocate 0 0 $chunk test f2fs_io fallocate 0 $chunk $chunk test f2fs_io fallocate 0 $((chunk*2)) $chunk test f2fs_io fiemap 0 $((chunk*3)) test Fiemap: offset = 0 len = 12288 logical addr. physical addr. length flags 0 0000000000000000 000000068c600000 0000000000400000 00001088 1 0000000000400000 000000003d400000 0000000000001000 00001088 2 0000000000401000 00000003eb200000 0000000000200000 00001088 3 0000000000601000 00000005e4200000 0000000000001000 00001088 4 0000000000602000 0000000605400000 0000000000200000 00001089 Cc: stable@vger.kernel.org Fixes: f5a53edcf01e ("f2fs: support aligned pinned file") Reviewed-by: Yunji Kang Reviewed-by: Yeongjin Gil Reviewed-by: Sungjong Seo Signed-off-by: Sunmin Jeong Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode

2026-07-04T11:45:05+00:00

commit e0288584baa5dc41df4a829a023c4c1b33fe53d7 upstream. - ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink - f2fs_gc - gc_data_segment - ra_data_block(cow_inode) - mapping = F2FS_I(inode)->atomic_inode->i_mapping : f2fs_is_cow_file(cow_inode) is true - f2fs_evict_inode(atomic_inode) - clear_inode_flag(fi->cow_inode, FI_COW_FILE) - F2FS_I(fi->cow_inode)->atomic_inode = NULL ... - truncate_inode_pages_final(atomic_inode) - f2fs_grab_cache_folio(mapping) : create folio in atomic_inode->mapping - clear_inode(atomic_inode) - BUG_ON(atomic_inode->i_data.nrpages) We need to add a reference on fi->atomic_inode before using its mapping field during garbage collection, otherwise, it will cause UAF issue. Cc: stable@kernel.org Cc: Daeho Jeong Cc: Sunmin Jeong Fixes: 3db1de0e582c ("f2fs: change the current atomic write way") Fixes: f18d00769336 ("f2fs: use meta inode for GC of COW file") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: validate compress cache inode only when enabled

2026-07-04T11:45:05+00:00

commit 5073c66a96a9c23c0c2533ed4ed06e42f9021208 upstream. F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled. When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead. Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid. Cc: stable@kernel.org Fixes: 6ce19aff0b8c ("f2fs: compress: add compress_inode to cache compressed blocks") Signed-off-by: Wenjie Qi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: validate orphan inode entry count

2026-07-04T11:45:05+00:00

commit 846c499a65816d13f1186e3090e825e8bb8bcb8b upstream. f2fs_recover_orphan_inodes() trusts the orphan block entry_count when replaying orphan inodes from the checkpoint pack. A corrupted entry_count larger than F2FS_ORPHANS_PER_BLOCK makes the recovery loop read past the ino[] array and interpret footer or following data as inode numbers. On a crafted image, mounting an unpatched kernel can drive orphan recovery into f2fs_bug_on() and panic the kernel. Validate entry_count before consuming entries so corrupted checkpoint data fails the mount with -EFSCORRUPTED and requests fsck instead. Set ERROR_INCONSISTENT_ORPHAN as well, so the corruption reason can be recorded in the superblock s_errors[] field. This gives fsck a persistent hint even though mount-time orphan recovery failure may leave no chance to persist SBI_NEED_FSCK through a checkpoint. Cc: stable@kernel.org Fixes: 127e670abfa7 ("f2fs: add checkpoint operations") Signed-off-by: Wenjie Qi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman