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BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xbc8/0xde0 fs/ext4/extents.c:953
Read of size 4 at addr ffff88808208c578 by task syz-executor.1/14361

CPU: 0 PID: 14361 Comm: syz-executor.1 Not tainted 6.5.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:475
 kasan_report+0x175/0x1b0 mm/kasan/report.c:588
 ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
 ext4_find_extent+0xbc8/0xde0 fs/ext4/extents.c:953
 ext4_ext_map_blocks+0x2d1/0x71d0 fs/ext4/extents.c:4101
 ext4_map_blocks+0x405/0x1cb0 fs/ext4/inode.c:548
 _ext4_get_block+0x238/0x6a0 fs/ext4/inode.c:763
 ext4_block_write_begin+0x53d/0x1570 fs/ext4/inode.c:1043
 ext4_write_begin+0x619/0x10b0
 ext4_da_write_begin+0x300/0xa40 fs/ext4/inode.c:2867
 generic_perform_write+0x31b/0x630 mm/filemap.c:3923
 ext4_buffered_write_iter+0xc6/0x350 fs/ext4/file.c:299
 ext4_file_write_iter+0x1df/0x1b10
 call_write_iter include/linux/fs.h:1871 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x782/0xaf0 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f98ca07cae9
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:00007f98cadd00c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f98ca19bf80 RCX: 00007f98ca07cae9
RDX: 000000000208e24b RSI: 0000000020000100 RDI: 0000000000000004
RBP: 00007f98ca0c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f98ca19bf80 R15: 00007ffc9d144888
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0002082300 refcount:1 mapcount:0 mapping:ffff8880796b22c8 index:0xea5 pfn:0x8208c
memcg:ffff888019f40000
aops:shmem_aops ino:6eb dentry name:"memfd:syzkaller"
flags: 0xfff0000008001e(referenced|uptodate|dirty|lru|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff0000008001e ffffea0000f9f9c8 ffffea0002082348 ffff8880796b22c8
raw: 0000000000000ea5 0000000000000000 00000001ffffffff ffff888019f40000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 14357, tgid 14355 (syz-executor.0), ts 523125426401, free_ts 522165721293
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1570
 prep_new_page mm/page_alloc.c:1577 [inline]
 get_page_from_freelist+0x31e8/0x3370 mm/page_alloc.c:3221
 __alloc_pages+0x255/0x670 mm/page_alloc.c:4477
 __folio_alloc+0x13/0x30 mm/page_alloc.c:4509
 vma_alloc_folio+0x48a/0x9a0 mm/mempolicy.c:2253
 shmem_alloc_folio mm/shmem.c:1579 [inline]
 shmem_alloc_and_acct_folio+0x5e7/0xe10 mm/shmem.c:1603
 shmem_get_folio_gfp+0x120f/0x3470 mm/shmem.c:1948
 shmem_get_folio mm/shmem.c:2079 [inline]
 shmem_write_begin+0x172/0x4e0 mm/shmem.c:2573
 generic_perform_write+0x31b/0x630 mm/filemap.c:3923
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4044
 call_write_iter include/linux/fs.h:1871 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x782/0xaf0 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1161 [inline]
 free_unref_page_prepare+0x903/0xa30 mm/page_alloc.c:2348
 free_unref_page_list+0x596/0x830 mm/page_alloc.c:2489
 release_pages+0x2193/0x2470 mm/swap.c:1042
 __folio_batch_release+0x84/0x100 mm/swap.c:1062
 folio_batch_release include/linux/pagevec.h:83 [inline]
 shmem_undo_range+0x6af/0x1ba0 mm/shmem.c:954
 shmem_truncate_range mm/shmem.c:1049 [inline]
 shmem_evict_inode+0x258/0x9f0 mm/shmem.c:1164
 evict+0x2a4/0x620 fs/inode.c:665
 __dentry_kill+0x436/0x650 fs/dcache.c:607
 dentry_kill+0xbb/0x290
 dput+0x1f3/0x420 fs/dcache.c:913
 __fput+0x628/0x950 fs/file_table.c:392
 task_work_run+0x24a/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86

Memory state around the buggy address:
 ffff88808208c400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808208c480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808208c500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                                ^
 ffff88808208c580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808208c600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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