==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:871 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xc0e/0xe00 fs/ext4/extents.c:991
Read of size 4 at addr ffff8881d8cbedf0 by task syz-executor142/342

CPU: 1 PID: 342 Comm: syz-executor142 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 __dump_stack+0x1e/0x20 lib/dump_stack.c:77
 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
 __kasan_report+0xef/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 ext4_ext_binsearch fs/ext4/extents.c:871 [inline]
 ext4_find_extent+0xc0e/0xe00 fs/ext4/extents.c:991
 ext4_ext_remove_space+0x2de/0x5850 fs/ext4/extents.c:3036
 ext4_punch_hole+0x6b4/0xae0 fs/ext4/inode.c:4492
 ext4_fallocate+0x25d/0x540 fs/ext4/extents.c:4991
 vfs_fallocate+0x587/0x700 fs/open.c:309
 madvise_remove mm/madvise.c:867 [inline]
 madvise_vma mm/madvise.c:950 [inline]
 do_madvise+0xd44/0x1ea0 mm/madvise.c:1172
 __do_sys_madvise mm/madvise.c:1198 [inline]
 __se_sys_madvise mm/madvise.c:1196 [inline]
 __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1196
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f3e4c6b7569
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3e4c675218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f3e4c73e6c8 RCX: 00007f3e4c6b7569
RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000
RBP: 00007f3e4c73e6c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3e4c70b554
R13: 0000200000000000 R14: 0000200000000180 R15: 0000200000000080

The buggy address belongs to the page:
page:ffffea0007632f80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 ffffea0007632f88 ffffea0007632f88 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff8881d8cbec80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881d8cbed00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881d8cbed80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                             ^
 ffff8881d8cbee00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881d8cbee80: 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:3390!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 342 Comm: syz-executor142 Tainted: G    B             5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:ext4_split_extent_at+0xe85/0xea0 fs/ext4/extents.c:3390
Code: 76 fb ff ff 48 89 df 49 89 f7 e8 46 a2 d4 ff 4c 89 fe e9 63 fb ff ff e8 49 a8 a6 ff 0f 0b e8 42 a8 a6 ff 0f 0b e8 3b a8 a6 ff <0f> 0b e8 34 a8 a6 ff 0f 0b e8 2d a8 a6 ff 0f 0b e8 26 a8 a6 ff 0f
RSP: 0018:ffff8881ee54f520 EFLAGS: 00010293
RAX: ffffffff81b8d6a5 RBX: 000000000000002a RCX: ffff8881f30cbf00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000002a
RBP: ffff8881ee54f690 R08: 0000000000000000 R09: 0000000050000028
R10: fffffbfff0ca7a5c R11: 1ffffffff0ca7a5c R12: 0000000000000000
R13: 0000000000000030 R14: 0000000000000030 R15: 0000000000000000
FS:  00007f3e4c6756c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e95b32a00e CR3: 00000001ef623000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_force_split_extent_at fs/ext4/extents.c:312 [inline]
 ext4_ext_remove_space+0x614/0x5850 fs/ext4/extents.c:3083
 ext4_punch_hole+0x6b4/0xae0 fs/ext4/inode.c:4492
 ext4_fallocate+0x25d/0x540 fs/ext4/extents.c:4991
 vfs_fallocate+0x587/0x700 fs/open.c:309
 madvise_remove mm/madvise.c:867 [inline]
 madvise_vma mm/madvise.c:950 [inline]
 do_madvise+0xd44/0x1ea0 mm/madvise.c:1172
 __do_sys_madvise mm/madvise.c:1198 [inline]
 __se_sys_madvise mm/madvise.c:1196 [inline]
 __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1196
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f3e4c6b7569
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3e4c675218 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f3e4c73e6c8 RCX: 00007f3e4c6b7569
RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000
RBP: 00007f3e4c73e6c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3e4c70b554
R13: 0000200000000000 R14: 0000200000000180 R15: 0000200000000080
Modules linked in:
---[ end trace cc2a6e4b0b553253 ]---
RIP: 0010:ext4_split_extent_at+0xe85/0xea0 fs/ext4/extents.c:3390
Code: 76 fb ff ff 48 89 df 49 89 f7 e8 46 a2 d4 ff 4c 89 fe e9 63 fb ff ff e8 49 a8 a6 ff 0f 0b e8 42 a8 a6 ff 0f 0b e8 3b a8 a6 ff <0f> 0b e8 34 a8 a6 ff 0f 0b e8 2d a8 a6 ff 0f 0b e8 26 a8 a6 ff 0f
RSP: 0018:ffff8881ee54f520 EFLAGS: 00010293
RAX: ffffffff81b8d6a5 RBX: 000000000000002a RCX: ffff8881f30cbf00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000002a
RBP: ffff8881ee54f690 R08: 0000000000000000 R09: 0000000050000028
R10: fffffbfff0ca7a5c R11: 1ffffffff0ca7a5c R12: 0000000000000000
R13: 0000000000000030 R14: 0000000000000030 R15: 0000000000000000
FS:  00007f3e4c6756c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e95b32a00e CR3: 00000001ef623000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400