==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbab/0xdb0 fs/ext4/extents.c:945
Read of size 4 at addr ffff888169552fb4 by task syz-executor.5/4346

CPU: 1 PID: 4346 Comm: syz-executor.5 Not tainted 5.10.194-syzkaller-00508-ga27512601c2d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:452
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 ext4_ext_binsearch fs/ext4/extents.c:826 [inline]
 ext4_find_extent+0xbab/0xdb0 fs/ext4/extents.c:945
 ext4_ext_map_blocks+0x26d/0x6be0 fs/ext4/extents.c:4097
 ext4_map_blocks+0x41d/0x1ec0 fs/ext4/inode.c:571
 _ext4_get_block+0x21b/0x610 fs/ext4/inode.c:793
 ext4_get_block_unwritten+0x2a/0x40 fs/ext4/inode.c:824
 ext4_block_write_begin+0x61e/0x13b0 fs/ext4/inode.c:1077
 ext4_write_begin+0x6fa/0x1730
 ext4_da_write_begin+0x49d/0xf60 fs/ext4/inode.c:3021
 generic_perform_write+0x2cd/0x570 mm/filemap.c:3506
 ext4_buffered_write_iter+0x482/0x610 fs/ext4/file.c:271
 ext4_file_write_iter+0x193/0x1c80 fs/ext4/file.c:685
 call_write_iter include/linux/fs.h:1976 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0xb55/0xe70 fs/read_write.c:605
 ksys_write+0x199/0x2c0 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:667
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7f985e5afae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f985d3320c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f985e6cef80 RCX: 00007f985e5afae9
RDX: 00000000000000a6 RSI: 0000000020000580 RDI: 0000000000000004
RBP: 00007f985e5fb47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f985e6cef80 R15: 00007fff99fec298

The buggy address belongs to the page:
page:ffffea0005a55480 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x169552
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea0005a38bc8 ffffea0005a554c8 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 0x100cca(GFP_HIGHUSER_MOVABLE), pid 3988, ts 309306133144, free_ts 309987455112
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x166/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5346
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 shmem_alloc_page+0x257/0x420 mm/shmem.c:1580
 shmem_alloc_and_acct_page+0x395/0x8e0 mm/shmem.c:1605
 shmem_getpage_gfp+0x891/0x2480 mm/shmem.c:1918
 shmem_fault+0x2d4/0x7b0 mm/shmem.c:2139
 __do_fault mm/memory.c:4023 [inline]
 do_read_fault mm/memory.c:4358 [inline]
 do_fault mm/memory.c:4486 [inline]
 handle_pte_fault+0x2371/0x3de0 mm/memory.c:4750
 __handle_mm_fault mm/memory.c:4903 [inline]
 handle_mm_fault+0x11d6/0x1a10 mm/memory.c:5297
 faultin_page mm/gup.c:902 [inline]
 __get_user_pages+0xb31/0x11b0 mm/gup.c:1121
 populate_vma_page_range mm/gup.c:1454 [inline]
 __mm_populate+0x363/0x520 mm/gup.c:1502
 mm_populate include/linux/mm.h:2768 [inline]
 vm_mmap_pgoff+0x264/0x390 mm/util.c:548
 ksys_mmap_pgoff+0xf8/0x1f0 mm/mmap.c:1698
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:95 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline]
 __x64_sys_mmap+0x103/0x120 arch/x86/kernel/sys_x86_64.c:86
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2ae/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443
 release_pages+0xea0/0xef0 mm/swap.c:1103
 __pagevec_release+0x84/0x100 mm/swap.c:1123
 pagevec_release include/linux/pagevec.h:88 [inline]
 shmem_undo_range+0x7d1/0x1a60 mm/shmem.c:965
 shmem_truncate_range mm/shmem.c:1069 [inline]
 shmem_evict_inode+0x215/0x9d0 mm/shmem.c:1169
 evict+0x2a3/0x6c0 fs/inode.c:577
 iput_final fs/inode.c:1697 [inline]
 iput+0x632/0x7e0 fs/inode.c:1723
 dentry_unlink_inode+0x2e5/0x3d0 fs/dcache.c:374
 __dentry_kill+0x447/0x650 fs/dcache.c:579
 dentry_kill+0xc0/0x2a0
 dput+0x160/0x310 fs/dcache.c:878
 __fput+0x4f4/0x760 fs/file_table.c:294
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x129/0x190 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xc83/0x2a50 kernel/exit.c:861

Memory state around the buggy address:
 ffff888169552e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888169552f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888169552f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                     ^
 ffff888169553000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888169553080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop5): ext4_map_blocks:602: inode #18: block 41: comm syz-executor.5: lblock 41 mapped to illegal pblock 41 (length 1)
EXT4-fs error (device loop5) in ext4_reserve_inode_write:5886: Out of memory
EXT4-fs error (device loop5): ext4_ext_truncate:4396: inode #18: comm syz-executor.5: mark_inode_dirty error
EXT4-fs error (device loop5) in ext4_reserve_inode_write:5886: Out of memory
EXT4-fs error (device loop5): ext4_truncate:4378: inode #18: comm syz-executor.5: mark_inode_dirty error