syzbot

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:827 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946
Read of size 4 at addr ffff888112f84610 by task syz-executor593/290

CPU: 1 PID: 290 Comm: syz-executor593 Not tainted 5.15.181-syzkaller-00405-gf93c8b5a9e60 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:827 [inline]
 ext4_find_extent+0xbeb/0xe20 fs/ext4/extents.c:946
 ext4_ext_remove_space+0x2bc/0x4180 fs/ext4/extents.c:2831
 ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4131
 ext4_fallocate+0x2b6/0x1de0 fs/ext4/extents.c:4763
 vfs_fallocate+0x4b4/0x590 fs/open.c:309
 ksys_fallocate fs/open.c:332 [inline]
 __do_sys_fallocate fs/open.c:340 [inline]
 __se_sys_fallocate fs/open.c:338 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:338
 x64_sys_call+0x7ec/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:286
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fea8e6f0c09
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 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:00007fea8e687168 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fea8e779718 RCX: 00007fea8e6f0c09
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00007fea8e779710 R08: 00007fea8e6876c0 R09: 0000000000000000
R10: 0000000000001a00 R11: 0000000000000246 R12: 00007fea8e77971c
R13: 000000000000006e R14: 00007fff58981830 R15: 00007fff58981918
 </TASK>

The buggy address belongs to the page:
page:ffffea00044be100 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x112f84
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea00044bdfc8 ffffea00044be208 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 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 272, ts 22960372679, free_ts 22984140913
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485
 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5781
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 do_anonymous_page mm/memory.c:4068 [inline]
 handle_pte_fault+0xe89/0x2680 mm/memory.c:4908
 __handle_mm_fault mm/memory.c:-1 [inline]
 do_handle_mm_fault+0x1a6d/0x1d50 mm/memory.c:5332
 handle_mm_fault include/linux/mm.h:1836 [inline]
 do_user_addr_fault+0x841/0x1180 arch/x86/mm/fault.c:1418
 handle_page_fault arch/x86/mm/fault.c:1509 [inline]
 exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1565
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534
 free_unref_page_list+0x134/0x9d0 mm/page_alloc.c:3671
 release_pages+0x1076/0x10d0 mm/swap.c:1009
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:320
 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:338
 unmap_region+0x315/0x360 mm/mmap.c:2680
 __do_munmap+0xa0e/0xfe0 mm/mmap.c:2913
 __vm_munmap+0x15b/0x2a0 mm/mmap.c:2966
 __do_sys_munmap mm/mmap.c:2992 [inline]
 __se_sys_munmap mm/mmap.c:2988 [inline]
 __x64_sys_munmap+0x6b/0x80 mm/mmap.c:2988
 x64_sys_call+0xc9/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:12
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff888112f84500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888112f84580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888112f84600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff888112f84680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888112f84700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0) in ext4_reserve_inode_write:5866: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_dirty_inode:6070: inode #18: comm syz-executor593: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_read_block_bitmap_nowait:476: comm syz-executor593: Invalid block bitmap block 0 in block_group 0
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0) in ext4_reserve_inode_write:5866: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_dirty_inode:6070: inode #18: comm syz-executor593: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0) in ext4_reserve_inode_write:5866: Corrupt filesystem
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_punch_hole:4144: inode #18: comm syz-executor593: mark_inode_dirty error
EXT4-fs (loop0): Remounting filesystem read-only