kernel/linux.git/fs/ext4/xattr.c, branch v6.18.21

ext4: fix iloc.bh leak in ext4_xattr_inode_update_ref

2026-01-23T10:21:28+00:00

commit d250bdf531d9cd4096fedbb9f172bb2ca660c868 upstream. The error branch for ext4_xattr_inode_update_ref forget to release the refcount for iloc.bh. Find this when review code. Fixes: 57295e835408 ("ext4: guard against EA inode refcount underflow in xattr update") Signed-off-by: Yang Erkun Reviewed-by: Baokun Li Reviewed-by: Zhang Yi Link: https://patch.msgid.link/20251213055706.3417529-1-yangerkun@huawei.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: xattr: fix null pointer deref in ext4_raw_inode()

2026-01-02T11:57:10+00:00

commit b97cb7d6a051aa6ebd57906df0e26e9e36c26d14 upstream. If ext4_get_inode_loc() fails (e.g. if it returns -EFSCORRUPTED), iloc.bh will remain set to NULL. Since ext4_xattr_inode_dec_ref_all() lacks error checking, this will lead to a null pointer dereference in ext4_raw_inode(), called right after ext4_get_inode_loc(). Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: c8e008b60492 ("ext4: ignore xattrs past end") Cc: stable@kernel.org Signed-off-by: Karina Yankevich Reviewed-by: Sergey Shtylyov Reviewed-by: Baokun Li Message-ID: <20251022093253.3546296-1-k.yankevich@omp.ru> Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: validate ea_ino and size in check_xattrs

2025-09-26T12:36:08+00:00

During xattr block validation, check_xattrs() processes xattr entries without validating that entries claiming to use EA inodes have non-zero sizes. Corrupted filesystems may contain xattr entries where e_value_size is zero but e_value_inum is non-zero, indicating invalid xattr data. Add validation in check_xattrs() to detect this corruption pattern early and return -EFSCORRUPTED, preventing invalid xattr entries from causing issues throughout the ext4 codebase. Cc: stable@kernel.org Suggested-by: Theodore Ts'o Reported-by: syzbot+4c9d23743a2409b80293@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=4c9d23743a2409b80293 Signed-off-by: Deepanshu Kartikey Signed-off-by: Theodore Ts'o Message-ID: <20250923133245.1091761-1-kartikey406@gmail.com> Signed-off-by: Theodore Ts'o

ext4: guard against EA inode refcount underflow in xattr update

2025-09-26T12:36:08+00:00

syzkaller found a path where ext4_xattr_inode_update_ref() reads an EA inode refcount that is already <= 0 and then applies ref_change (often -1). That lets the refcount underflow and we proceed with a bogus value, triggering errors like: EXT4-fs error: EA inode ref underflow: ref_count=-1 ref_change=-1 EXT4-fs warning: ea_inode dec ref err=-117 Make the invariant explicit: if the current refcount is non-positive, treat this as on-disk corruption, emit ext4_error_inode(), and fail the operation with -EFSCORRUPTED instead of updating the refcount. Delete the WARN_ONCE() as negative refcounts are now impossible; keep error reporting in ext4_error_inode(). This prevents the underflow and the follow-on orphan/cleanup churn. Reported-by: syzbot+0be4f339a8218d2a5bb1@syzkaller.appspotmail.com Fixes: https://syzbot.org/bug?extid=0be4f339a8218d2a5bb1 Cc: stable@kernel.org Co-developed-by: Albin Babu Varghese Signed-off-by: Albin Babu Varghese Signed-off-by: Ahmet Eray Karadag Message-ID: <20250920021342.45575-1-eraykrdg1@gmail.com> Signed-off-by: Theodore Ts'o

fs: ext4: change GFP_KERNEL to GFP_NOFS to avoid deadlock

2025-09-25T18:17:16+00:00

The parent function ext4_xattr_inode_lookup_create already uses GFP_NOFS for memory alloction, so the function ext4_xattr_inode_cache_find should use same gfp_flag. Signed-off-by: chuguangqing Signed-off-by: Theodore Ts'o

ext4: Refactor breaking condition for xattr_find_entry()

2025-07-17T14:41:05+00:00

Refactor the condition for breaking the loop within xattr_find_entry(). Elimate the usage of "<=" and take condition shortcut when "!cmp" is true. Originally, the condition was "(cmp <= 0 && (sorted || cmp == 0))", which means after it knows "cmp <= 0" is true, it has to check the value of "sorted" and "cmp". The checking of "cmp" here would be redundant since it has already checked it. Observing from the logic, when "cmp == 0" the branch is going to be true, no need to check "cmp == 0" again, so we only need to take shortcut when "cmp == 0", on the other hand, we'll check "sorted" when "cmp < 0". The refactor can shrink the generated code size by 44 bytes. Numerous instructions can be saved thus should also benefit execution efficiency as well. $ ./scripts/bloat-o-meter vmlinux_old vmlinux_new add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-44 (-44) Function old new delta xattr_find_entry 300 256 -44 Total: Before=22989434, After=22989390, chg -0.00% The test is done on kernel version 6.16 with x86_64 defconfig and gcc 13.3.0. Signed-off-by: I Hsin Cheng Link: https://patch.msgid.link/20250708020013.175728-1-richard120310@gmail.com Signed-off-by: Theodore Ts'o

ext4: replace ext4_writepage_trans_blocks()

2025-07-14T03:41:52+00:00

After ext4 supports large folios, the semantics of reserving credits in pages is no longer applicable. In most scenarios, reserving credits in extents is sufficient. Therefore, introduce ext4_chunk_trans_extent() to replace ext4_writepage_trans_blocks(). move_extent_per_page() is the only remaining location where we are still processing extents in pages. Suggested-by: Jan Kara Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://patch.msgid.link/20250707140814.542883-10-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o

ext4: remove sbi argument from ext4_chksum()

2025-05-20T14:31:12+00:00

Since ext4_chksum() no longer uses its sbi argument, remove it. Signed-off-by: Eric Biggers Reviewed-by: Baokun Li Link: https://patch.msgid.link/20250513053809.699974-2-ebiggers@kernel.org Signed-off-by: Theodore Ts'o

ext4: fix out-of-bound read in ext4_xattr_inode_dec_ref_all()

2025-03-18T04:15:19+00:00

There's issue as follows: BUG: KASAN: use-after-free in ext4_xattr_inode_dec_ref_all+0x6ff/0x790 Read of size 4 at addr ffff88807b003000 by task syz-executor.0/15172 CPU: 3 PID: 15172 Comm: syz-executor.0 Call Trace: __dump_stack lib/dump_stack.c:82 [inline] dump_stack+0xbe/0xfd lib/dump_stack.c:123 print_address_description.constprop.0+0x1e/0x280 mm/kasan/report.c:400 __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560 kasan_report+0x3a/0x50 mm/kasan/report.c:585 ext4_xattr_inode_dec_ref_all+0x6ff/0x790 fs/ext4/xattr.c:1137 ext4_xattr_delete_inode+0x4c7/0xda0 fs/ext4/xattr.c:2896 ext4_evict_inode+0xb3b/0x1670 fs/ext4/inode.c:323 evict+0x39f/0x880 fs/inode.c:622 iput_final fs/inode.c:1746 [inline] iput fs/inode.c:1772 [inline] iput+0x525/0x6c0 fs/inode.c:1758 ext4_orphan_cleanup fs/ext4/super.c:3298 [inline] ext4_fill_super+0x8c57/0xba40 fs/ext4/super.c:5300 mount_bdev+0x355/0x410 fs/super.c:1446 legacy_get_tree+0xfe/0x220 fs/fs_context.c:611 vfs_get_tree+0x8d/0x2f0 fs/super.c:1576 do_new_mount fs/namespace.c:2983 [inline] path_mount+0x119a/0x1ad0 fs/namespace.c:3316 do_mount+0xfc/0x110 fs/namespace.c:3329 __do_sys_mount fs/namespace.c:3540 [inline] __se_sys_mount+0x219/0x2e0 fs/namespace.c:3514 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1 Memory state around the buggy address: ffff88807b002f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88807b002f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88807b003000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88807b003080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88807b003100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff Above issue happens as ext4_xattr_delete_inode() isn't check xattr is valid if xattr is in inode. To solve above issue call xattr_check_inode() check if xattr if valid in inode. In fact, we can directly verify in ext4_iget_extra_inode(), so that there is no divergent verification. Fixes: e50e5129f384 ("ext4: xattr-in-inode support") Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://patch.msgid.link/20250208063141.1539283-3-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o

ext4: introduce ITAIL helper

2025-03-18T04:14:47+00:00

Introduce ITAIL helper to get the bound of xattr in inode. Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://patch.msgid.link/20250208063141.1539283-2-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o