From: Zhang Yi yi.zhang@huawei.com
[ Upstream commit b5e58bcd79625423487fa3ecba8e8411b5396327 ]
Punching a hole with a start offset that exceeds max_end is not permitted and will result in a negative length in the truncate_inode_partial_folio() function while truncating the page cache, potentially leading to undesirable consequences.
A simple reproducer:
truncate -s 9895604649994 /mnt/foo xfs_io -c "pwrite 8796093022208 4096" /mnt/foo xfs_io -c "fpunch 8796093022213 25769803777" /mnt/foo
kernel BUG at include/linux/highmem.h:275! Oops: invalid opcode: 0000 [#1] SMP PTI CPU: 3 UID: 0 PID: 710 Comm: xfs_io Not tainted 6.15.0-rc3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:zero_user_segments.constprop.0+0xd7/0x110 RSP: 0018:ffffc90001cf3b38 EFLAGS: 00010287 RAX: 0000000000000005 RBX: ffffea0001485e40 RCX: 0000000000001000 RDX: 000000000040b000 RSI: 0000000000000005 RDI: 000000000040b000 RBP: 000000000040affb R08: ffff888000000000 R09: ffffea0000000000 R10: 0000000000000003 R11: 00000000fffc7fc5 R12: 0000000000000005 R13: 000000000040affb R14: ffffea0001485e40 R15: ffff888031cd3000 FS: 00007f4f63d0b780(0000) GS:ffff8880d337d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000001ae0b038 CR3: 00000000536aa000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> truncate_inode_partial_folio+0x3dd/0x620 truncate_inode_pages_range+0x226/0x720 ? bdev_getblk+0x52/0x3e0 ? ext4_get_group_desc+0x78/0x150 ? crc32c_arch+0xfd/0x180 ? __ext4_get_inode_loc+0x18c/0x840 ? ext4_inode_csum+0x117/0x160 ? jbd2_journal_dirty_metadata+0x61/0x390 ? __ext4_handle_dirty_metadata+0xa0/0x2b0 ? kmem_cache_free+0x90/0x5a0 ? jbd2_journal_stop+0x1d5/0x550 ? __ext4_journal_stop+0x49/0x100 truncate_pagecache_range+0x50/0x80 ext4_truncate_page_cache_block_range+0x57/0x3a0 ext4_punch_hole+0x1fe/0x670 ext4_fallocate+0x792/0x17d0 ? __count_memcg_events+0x175/0x2a0 vfs_fallocate+0x121/0x560 ksys_fallocate+0x51/0xc0 __x64_sys_fallocate+0x24/0x40 x64_sys_call+0x18d2/0x4170 do_syscall_64+0xa7/0x220 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by filtering out cases where the punching start offset exceeds max_end.
Fixes: 982bf37da09d ("ext4: refactor ext4_punch_hole()") Reported-by: Liebes Wang wanghaichi0403@gmail.com Closes: https://lore.kernel.org/linux-ext4/ac3a58f6-e686-488b-a9ee-fc041024e43d@huaw... Tested-by: Liebes Wang wanghaichi0403@gmail.com Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Jan Kara jack@suse.cz Reviewed-by: Baokun Li libaokun1@huawei.com Link: https://patch.msgid.link/20250506012009.3896990-1-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index fe1d19d920a96..eb092133c6b88 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4009,7 +4009,7 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) max_end = EXT4_SB(sb)->s_bitmap_maxbytes - sb->s_blocksize;
/* No need to punch hole beyond i_size */ - if (offset >= inode->i_size) + if (offset >= inode->i_size || offset >= max_end) return 0;
/*