Hi Edward, On 2025/6/15 13:05, Edward Adam Davis wrote:
In this case, advise contains Z_EROFS_ADVISE_EXTENTS, Z_EROFS_ADVISE_BIG_PCLUSTER_1, Z_EROFS_ADVISE_BIG_PCLUSTER_2 at the same time, and following 1 and 2 are met, WARN_ON_ONCE(iter->iomap.offset > iter->pos) in iomap_iter_done() is triggered.1. When Z_EROFS_ADVISE_EXTENTS exists, z_erofs_fill_inode_lazy() is exited after z_extents is set, which skips the check of big pcluster; 2. When the condition "lstart < lend" is met in z_erofs_map_blocks_ext(), m_la is updated, and m_la is used to update iomap->offset in z_erofs_iomap_begin_report(); Fixes: 1d191b4ca51d ("erofs: implement encoded extent metadata") Reported-by: syzbot+d8f000c609f05f52d...@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d8f000c609f05f52d9b5 Tested-by: syzbot+d8f000c609f05f52d...@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis <eada...@qq.com>
Z_EROFS_ADVISE_BIG_PCLUSTER_1 and Z_EROFS_ADVISE_BIG_PCLUSTER_2 are valid only for !Z_EROFS_ADVISE_EXTENTS, so I don't think this change is a proper solution. From the commit message above, I don't get the root cause either. Anyway, I will seek time to look into this issue later. Thanks, Gao Xiang
