WARNING: The mand mount option has been deprecated and
         and is ignored by this kernel. Remove the mand
         option from the mount to silence this warning.
=======================================================
EXT4-fs: Ignoring removed oldalloc option
EXT4-fs: Ignoring removed orlov option
EXT4-fs (loop2): mounted filesystem without journal. Quota mode: writeback.
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:953
Read of size 4 at addr ffff88812fa1a018 by task syz.2.17/362

CPU: 0 PID: 362 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350
 ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
 ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:953
 ext4_ext_remove_space+0x2de/0x40d0 fs/ext4/extents.c:2834
 ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4147
 ext4_fallocate+0x2b6/0x1dc0 fs/ext4/extents.c:4767
 vfs_fallocate+0x4c5/0x5a0 fs/open.c:324
 ioctl_preallocate fs/ioctl.c:290 [inline]
 file_ioctl fs/ioctl.c:333 [inline]
 do_vfs_ioctl+0x19cb/0x1cd0 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x9f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fed5259c799
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:00007ffd9d148998 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed52815fa0 RCX: 00007fed5259c799
RDX: 00002000000000c0 RSI: 0000000040305829 RDI: 0000000000000005
RBP: 00007fed52632c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed52815fac R14: 00007fed52815fa0 R15: 00007fed52815fa0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004be8680 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12fa1a
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0004be8688 ffffea0004be8688 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:
 ffff88812fa19f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812fa19f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88812fa1a000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff88812fa1a080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88812fa1a100: 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:3190!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 362 Comm: syz.2.17 Tainted: G    B              syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_split_extent_at+0xf62/0xf80 fs/ext4/extents.c:3190
Code: ff ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c 3f fb ff ff 4c 89 f7 49 89 f7 e8 9b b7 cf ff 4c 89 fe e9 2c fb ff ff e8 4e 7b 8a ff <0f> 0b e8 47 7b 8a ff 0f 0b e8 40 7b 8a ff 0f 0b e8 39 7b 8a ff 0f
RSP: 0018:ffffc900007a74c0 EFLAGS: 00010293
RAX: ffffffff81e6f382 RBX: 0000000000000000 RCX: ffff8881130b0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000041
RBP: ffffc900007a7630 R08: 0000000000000000 R09: 0000000050000028
R10: dffffc0000000000 R11: fffffbfff0f6e4fd R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881149b1100
FS:  000055556dd21500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 000000010ed76000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_force_split_extent_at fs/ext4/extents.c:338 [inline]
 ext4_ext_remove_space+0x652/0x40d0 fs/ext4/extents.c:2881
 ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4147
 ext4_fallocate+0x2b6/0x1dc0 fs/ext4/extents.c:4767
 vfs_fallocate+0x4c5/0x5a0 fs/open.c:324
 ioctl_preallocate fs/ioctl.c:290 [inline]
 file_ioctl fs/ioctl.c:333 [inline]
 do_vfs_ioctl+0x19cb/0x1cd0 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x9f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fed5259c799
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:00007ffd9d148998 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed52815fa0 RCX: 00007fed5259c799
RDX: 00002000000000c0 RSI: 0000000040305829 RDI: 0000000000000005
RBP: 00007fed52632c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed52815fac R14: 00007fed52815fa0 R15: 00007fed52815fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_split_extent_at+0xf62/0xf80 fs/ext4/extents.c:3190
Code: ff ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c 3f fb ff ff 4c 89 f7 49 89 f7 e8 9b b7 cf ff 4c 89 fe e9 2c fb ff ff e8 4e 7b 8a ff <0f> 0b e8 47 7b 8a ff 0f 0b e8 40 7b 8a ff 0f 0b e8 39 7b 8a ff 0f
RSP: 0018:ffffc900007a74c0 EFLAGS: 00010293
RAX: ffffffff81e6f382 RBX: 0000000000000000 RCX: ffff8881130b0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000041
RBP: ffffc900007a7630 R08: 0000000000000000 R09: 0000000050000028
R10: dffffc0000000000 R11: fffffbfff0f6e4fd R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881149b1100
FS:  000055556dd21500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc50ba1f000 CR3: 000000010ed76000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400