ext4 filesystem being mounted at /0/file1 supports timestamps until 2038-01-19 (0x7fffffff)
==================================================================
BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2602 [inline]
BUG: KASAN: use-after-free in ext4_ext_remove_space+0x348b/0x40d0 fs/ext4/extents.c:2940
Read of size 4 at addr ffff888134d7d69c by task syz.2.953/3338

CPU: 1 PID: 3338 Comm: syz.2.953 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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_rm_leaf fs/ext4/extents.c:2602 [inline]
 ext4_ext_remove_space+0x348b/0x40d0 fs/ext4/extents.c:2940
 ext4_ext_truncate+0x200/0x320 fs/ext4/extents.c:4476
 ext4_truncate+0x9be/0xfb0 fs/ext4/inode.c:4304
 ext4_setattr+0x1249/0x1bb0 fs/ext4/inode.c:5670
 notify_change+0xcc3/0xf80 fs/attr.c:499
 do_truncate+0x1ac/0x240 fs/open.c:66
 handle_truncate fs/namei.c:3292 [inline]
 do_open fs/namei.c:3637 [inline]
 path_openat+0x28f0/0x2f80 fs/namei.c:3790
 do_filp_open+0x1f1/0x430 fs/namei.c:3817
 do_sys_openat2+0x15e/0x810 fs/open.c:1343
 do_sys_open fs/open.c:1359 [inline]
 __do_sys_creat fs/open.c:1437 [inline]
 __se_sys_creat fs/open.c:1431 [inline]
 __x64_sys_creat+0x8e/0xb0 fs/open.c:1431
 x64_sys_call+0x116/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:86
 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: 0033:0x7f394ab9ce59
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:00007f394bad3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f394ae15fa0 RCX: 00007f394ab9ce59
RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000200000000100
RBP: 00007f394ac32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f394ae16038 R14: 00007f394ae15fa0 R15: 00007ffc914d2a08
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0004d35f40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x134d7d
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 dead000000000100 dead000000000122 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 0x8140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO|__GFP_CMA), pid 297, tgid 294 (syz-execprog), ts 156577690010, free_ts 279064651711
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4585
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5929
 __folio_alloc+0x12/0x40 mm/page_alloc.c:5962
 __folio_alloc_node include/linux/gfp.h:245 [inline]
 folio_alloc include/linux/gfp.h:274 [inline]
 alloc_page_vma include/linux/gfp.h:283 [inline]
 do_anonymous_page mm/memory.c:4286 [inline]
 handle_pte_fault mm/memory.c:5181 [inline]
 __handle_mm_fault mm/memory.c:5325 [inline]
 handle_mm_fault+0x1972/0x26c0 mm/memory.c:5465
 do_user_addr_fault+0x905/0x1050 arch/x86/mm/fault.c:1321
 handle_page_fault arch/x86/mm/fault.c:1464 [inline]
 exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1517
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1580 [inline]
 free_pcp_prepare mm/page_alloc.c:1654 [inline]
 free_unref_page_prepare+0x7f8/0x800 mm/page_alloc.c:3620
 free_unref_page_list+0x117/0x8c0 mm/page_alloc.c:3771
 release_pages+0xc93/0xcf0 mm/swap.c:1053
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:316
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu mm/mmu_gather.c:261 [inline]
 tlb_finish_mmu+0x1aa/0x370 mm/mmu_gather.c:361
 zap_page_range_single+0x47d/0x520 mm/memory.c:1824
 madvise_dontneed_single_vma mm/madvise.c:842 [inline]
 madvise_dontneed_free mm/madvise.c:944 [inline]
 madvise_vma_behavior mm/madvise.c:1083 [inline]
 madvise_walk_vmas mm/madvise.c:1308 [inline]
 do_madvise+0x17fb/0x3290 mm/madvise.c:1487
 __do_sys_madvise mm/madvise.c:1500 [inline]
 __se_sys_madvise mm/madvise.c:1498 [inline]
 __x64_sys_madvise+0xa9/0xc0 mm/madvise.c:1498
 x64_sys_call+0x99e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:29
 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

Memory state around the buggy address:
 ffff888134d7d580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888134d7d600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888134d7d680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff888134d7d700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888134d7d780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop2): ext4_free_blocks:6220: comm syz.2.953: Freeing blocks not in datazone - block = 72241349923500, count = 14912
EXT4-fs error (device loop2): ext4_free_blocks:6220: comm syz.2.953: Freeing blocks not in datazone - block = 0, count = 4780
EXT4-fs error (device loop2): ext4_free_blocks:6220: comm syz.2.953: Freeing blocks not in datazone - block = 0, count = 0