EXT4-fs: Ignoring removed oldalloc option
EXT4-fs: Ignoring removed orlov option
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: writeback.
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:847 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0x8f4/0xaa8 fs/ext4/extents.c:962
Read of size 4 at addr ffff0000fa8fb018 by task syz.0.318/5525

CPU: 0 PID: 5525 Comm: syz.0.318 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load4_noabort+0x2c/0x38 mm/kasan/report_generic.c:350
 ext4_ext_binsearch fs/ext4/extents.c:847 [inline]
 ext4_find_extent+0x8f4/0xaa8 fs/ext4/extents.c:962
 ext4_ext_remove_space+0x2c0/0x3ac4 fs/ext4/extents.c:2845
 ext4_punch_hole+0x694/0xb58 fs/ext4/inode.c:4141
 ext4_fallocate+0x224/0x1abc fs/ext4/extents.c:4818
 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323
 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290
 file_ioctl fs/ioctl.c:-1 [inline]
 do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:00000000f4bcac84 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x13a8fb
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003ea3f08 fffffc0003ea3e88 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000fa8faf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000fa8faf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000fa8fb000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff0000fa8fb080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000fa8fb100: 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:3200!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 5525 Comm: syz.0.318 Tainted: G    B              syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext4_split_extent_at+0xd78/0xdcc fs/ext4/extents.c:3200
lr : ext4_split_extent_at+0xd78/0xdcc fs/ext4/extents.c:3200
sp : ffff800020f27380
x29: ffff800020f27480 x28: 0000000000000041 x27: dfff800000000000
x26: ffff0000fa952c18 x25: ffff0000fa952c1c x24: 0000000000000002
x23: 0000000000000000 x22: ffff0000fa952c1e x21: 1fffe0001f52a583
x20: 0000000000000000 x19: 0000000000000000 x18: ffff800011b9bf60
x17: 1fffe00033eaa57e x16: ffff80000804309c x15: 0000000040000000
x14: 0000000000000001 x13: 1ffff00002fc1b6c x12: 0000000000080000
x11: 00000000000184fe x10: ffff800021dfc000 x9 : ffff800008d347d4
x8 : 00000000000184ff x7 : 0000000000000004 x6 : ffff800008257984
x5 : 0000000050000028 x4 : 0000000000000000 x3 : ffff800008d3455c
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000041
Call trace:
 ext4_split_extent_at+0xd78/0xdcc fs/ext4/extents.c:3200
 ext4_force_split_extent_at fs/ext4/extents.c:342 [inline]
 ext4_ext_remove_space+0x63c/0x3ac4 fs/ext4/extents.c:2892
 ext4_punch_hole+0x694/0xb58 fs/ext4/inode.c:4141
 ext4_fallocate+0x224/0x1abc fs/ext4/extents.c:4818
 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323
 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290
 file_ioctl fs/ioctl.c:-1 [inline]
 do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: aa1303e0 97eecb30 17ffff2e 97dddb72 (d4210000) 
---[ end trace 0000000000000000 ]---