==================================================================
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 ffff8881227d86f4 by task syz-executor220/282

CPU: 1 PID: 282 Comm: syz-executor220 Not tainted 5.10.238-syzkaller-00008-g59e9a7228857 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 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_remove_space+0x306/0x4910 fs/ext4/extents.c:2826
 ext4_punch_hole+0x6f8/0xad0 fs/ext4/inode.c:4217
 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4756
 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+0x12cf/0x1df0 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: 0033:0x7f576266bbb9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc91a9fee8 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f576266bbb9
RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000
RBP: 00007f57626de610 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc91aa00c8 R14: 0000000000000001 R15: 0000000000000001

The buggy address belongs to the page:
page:ffffea000489f600 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x1227d8
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea0004804108 ffffea0004831308 0000000000000000
raw: 0000000000000001 0000000000000002 00000000ffffff7f 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 284, ts 20910812020, free_ts 20911291023
 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+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357
 __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]
 do_anonymous_page mm/memory.c:3963 [inline]
 handle_pte_fault+0x1719/0x3750 mm/memory.c:4786
 __handle_mm_fault mm/memory.c:4944 [inline]
 handle_mm_fault+0xf3f/0x16a0 mm/memory.c:5358
 do_user_addr_fault+0x5a2/0xc80 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+0x12e/0x9b0 mm/page_alloc.c:3443
 release_pages+0xe38/0xe80 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 mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x175/0x300 mm/mmu_gather.c:326
 unmap_region+0x32c/0x380 mm/mmap.c:2799
 __do_munmap+0x63c/0x850 mm/mmap.c:3029
 __vm_munmap mm/mmap.c:3082 [inline]
 __do_sys_munmap mm/mmap.c:3108 [inline]
 __se_sys_munmap+0x127/0x1b0 mm/mmap.c:3104
 __x64_sys_munmap+0x5b/0x70 mm/mmap.c:3104
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff8881227d8580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881227d8600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881227d8680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                             ^
 ffff8881227d8700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881227d8780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:3180!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 282 Comm: syz-executor220 Tainted: G    B             5.10.238-syzkaller-00008-g59e9a7228857 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:ext4_split_extent_at+0xe6e/0xe90 fs/ext4/extents.c:3180
Code: 48 89 df 48 89 74 24 68 e8 2f 8c d3 ff 48 8b 74 24 68 e9 5a fb ff ff e8 00 9c 99 ff 0f 0b e8 f9 9b 99 ff 0f 0b e8 f2 9b 99 ff <0f> 0b e8 eb 9b 99 ff 0f 0b e8 e4 9b 99 ff 0f 0b e8 dd 9b 99 ff 0f
RSP: 0018:ffffc90000b774a0 EFLAGS: 00010293
RAX: ffffffff81c9f81e RBX: 0000000000000000 RCX: ffff888106dee2c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000002a
RBP: ffffc90000b77610 R08: 0000000000000000 R09: 0000000050000028
R10: fffffbfff0d8e448 R11: 1ffffffff0d8e448 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff110244fbbff R15: 0000000000000000
FS:  000055556438b380(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f256175f000 CR3: 00000001213c2000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_force_split_extent_at fs/ext4/extents.c:318 [inline]
 ext4_ext_remove_space+0x677/0x4910 fs/ext4/extents.c:2873
 ext4_punch_hole+0x6f8/0xad0 fs/ext4/inode.c:4217
 ext4_fallocate+0x271/0x1a70 fs/ext4/extents.c:4756
 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+0x12cf/0x1df0 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: 0033:0x7f576266bbb9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc91a9fee8 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f576266bbb9
RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000
RBP: 00007f57626de610 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc91aa00c8 R14: 0000000000000001 R15: 0000000000000001
Modules linked in:
---[ end trace 2d7c96c617f901c8 ]---
RIP: 0010:ext4_split_extent_at+0xe6e/0xe90 fs/ext4/extents.c:3180
Code: 48 89 df 48 89 74 24 68 e8 2f 8c d3 ff 48 8b 74 24 68 e9 5a fb ff ff e8 00 9c 99 ff 0f 0b e8 f9 9b 99 ff 0f 0b e8 f2 9b 99 ff <0f> 0b e8 eb 9b 99 ff 0f 0b e8 e4 9b 99 ff 0f 0b e8 dd 9b 99 ff 0f
RSP: 0018:ffffc90000b774a0 EFLAGS: 00010293
RAX: ffffffff81c9f81e RBX: 0000000000000000 RCX: ffff888106dee2c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000002a
RBP: ffffc90000b77610 R08: 0000000000000000 R09: 0000000050000028
R10: fffffbfff0d8e448 R11: 1ffffffff0d8e448 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff110244fbbff R15: 0000000000000000
FS:  000055556438b380(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f256175f000 CR3: 00000001213c2000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400