EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 ================================================================== BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:827 [inline] BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946 Read of size 4 at addr ffff888122828088 by task kworker/u4:2/43 CPU: 0 PID: 43 Comm: kworker/u4:2 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0xf1/0x140 mm/kasan/report.c:444 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 ext4_ext_binsearch fs/ext4/extents.c:827 [inline] ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946 ext4_ext_map_blocks+0x207/0x61e0 fs/ext4/extents.c:4166 ext4_map_blocks+0x988/0x1b30 fs/ext4/inode.c:674 mpage_map_one_extent fs/ext4/inode.c:2421 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_writepages+0x123f/0x3090 fs/ext4/inode.c:2842 do_writepages+0x473/0x6c0 mm/page-writeback.c:2388 __writeback_single_inode+0xd5/0x9c0 fs/fs-writeback.c:1657 writeback_sb_inodes+0xa10/0x1610 fs/fs-writeback.c:1940 wb_writeback+0x40b/0x9d0 fs/fs-writeback.c:2116 wb_do_writeback fs/fs-writeback.c:2263 [inline] wb_workfn+0x3ac/0xf30 fs/fs-writeback.c:2304 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the page: page:ffffea00048a0a00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x2 pfn:0x122828 flags: 0x4000000000000000(zone=1) raw: 4000000000000000 ffffea00048a0c08 ffff8881f703c650 0000000000000000 raw: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?) Memory state around the buggy address: ffff888122827f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888122828000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888122828080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888122828100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888122828180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 28 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs (loop0): Total free blocks count 0 EXT4-fs (loop0): Free/Dirty block details EXT4-fs (loop0): free_blocks=16 EXT4-fs (loop0): dirty_blocks=0 EXT4-fs (loop0): Block reservation details EXT4-fs (loop0): i_reserved_data_blocks=0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 15 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): ext4_ext_map_blocks:4184: inode #19: comm kworker/u4:2: bad extent address lblock: 0, depth: 1 pblock 0 EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 16 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0 EXT4-fs error (device loop0) in ext4_reserve_inode_write:5881: Corrupt filesystem EXT4-fs error (device loop0): __ext4_ext_dirty:183: inode #19: comm kworker/u4:2: mark_inode_dirty error EXT4-fs (loop0): Delayed block allocation failed for inode 19 at logical offset 0 with max blocks 2 with error 117 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs error (device loop0): __ext4_get_inode_loc:4358: comm kworker/u4:2: Invalid inode table block 0 in block_group 0