EXT4-fs error (device loop2): ext4_lookup:1830: inode #16: comm syz.2.99: iget: bad extended attribute block 8
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945
Read of size 4 at addr ffff88812c5c1018 by task syz.2.99/698

CPU: 0 PID: 698 Comm: syz.2.99 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
 ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:945
 ext4_ext_map_blocks+0x20b/0x5dd0 fs/ext4/extents.c:4160
 ext4_map_blocks+0x985/0x1bd0 fs/ext4/inode.c:674
 mpage_map_one_extent fs/ext4/inode.c:2452 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline]
 ext4_writepages+0x136a/0x2eb0 fs/ext4/inode.c:2873
 do_writepages+0x128/0x280 mm/page-writeback.c:2380
 __filemap_fdatawrite_range+0x2a0/0x350 mm/filemap.c:427
 filemap_write_and_wait_range+0x65/0x290 mm/filemap.c:660
 ext4_punch_hole+0x120/0xad0 fs/ext4/inode.c:4118
 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4758
 vfs_fallocate+0x4b4/0x590 fs/open.c:310
 madvise_remove mm/madvise.c:880 [inline]
 madvise_vma_behavior mm/madvise.c:904 [inline]
 madvise_walk_vmas mm/madvise.c:1131 [inline]
 do_madvise+0x1443/0x1d70 mm/madvise.c:1308
 __do_sys_madvise mm/madvise.c:1322 [inline]
 __se_sys_madvise mm/madvise.c:1320 [inline]
 __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1320
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc3acedff79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc3ab93b028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007fc3ad159fa0 RCX: 00007fc3acedff79
RDX: 0000000000000009 RSI: 0000000000600003 RDI: 0000200000000000
RBP: 00007fc3acf767e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc3ad15a038 R14: 00007fc3ad159fa0 R15: 00007ffe0e43f2f8

The buggy address belongs to the page:
page:ffffea0004b17040 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12c5c1
flags: 0x4000000000000000()
raw: 4000000000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x8100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|0x8000000), pid 684, ts 39575513934, free_ts 39612981691
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x223b/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x290/0x620 mm/page_alloc.c:5370
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 wp_page_copy+0x1e5/0x15f0 mm/memory.c:3166
 do_wp_page+0x9a6/0xc80 mm/memory.c:-1
 handle_pte_fault+0xac1/0x3750 mm/memory.c:4810
 __handle_mm_fault mm/memory.c:4944 [inline]
 handle_mm_fault+0xf81/0x1710 mm/memory.c:5358
 do_user_addr_fault+0x5a8/0xc90 arch/x86/mm/fault.c:1362
 handle_page_fault arch/x86/mm/fault.c:1428 [inline]
 exc_page_fault+0x5a/0xc0 arch/x86/mm/fault.c:1484
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x129/0x9c0 mm/page_alloc.c:3443
 release_pages+0xe52/0xea0 mm/swap.c:1103
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:356
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu+0xdf/0x190 mm/mmu_gather.c:247
 zap_pte_range mm/memory.c:1385 [inline]
 zap_pmd_range mm/memory.c:1435 [inline]
 zap_pud_range mm/memory.c:1464 [inline]
 zap_p4d_range mm/memory.c:1485 [inline]
 unmap_page_range+0x1d66/0x2130 mm/memory.c:1506
 unmap_single_vma mm/memory.c:1551 [inline]
 unmap_vmas+0x25f/0x360 mm/memory.c:1583
 exit_mmap+0x309/0x590 mm/mmap.c:3385
 __mmput+0x93/0x2f0 kernel/fork.c:1153
 mmput+0x4e/0x150 kernel/fork.c:1176
 exit_mm kernel/exit.c:539 [inline]
 do_exit+0x9ec/0x2500 kernel/exit.c:859
 do_group_exit+0x141/0x310 kernel/exit.c:986
 get_signal+0xf7d/0x12e0 kernel/signal.c:2793
 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199

Memory state around the buggy address:
 ffff88812c5c0f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812c5c0f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88812c5c1000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff88812c5c1080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812c5c1100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs (loop2): Delayed block allocation failed for inode 19 at logical offset 168 with max blocks 8 with error 117
EXT4-fs (loop2): This should not happen!! Data will be lost