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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 ffff888074240210 by task kworker/u4:0/11

CPU: 0 PID: 11 Comm: kworker/u4:0 Not tainted 6.7.0-rc1-syzkaller-00019-gc42d9eeef8e5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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+0x142/0x170 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+0x2cb/0x7150 fs/ext4/extents.c:4101
 ext4_map_blocks+0xa2f/0x1cd0 fs/ext4/inode.c:621
 ext4_convert_unwritten_extents+0x2f3/0x6c0 fs/ext4/extents.c:4811
 ext4_convert_unwritten_io_end_vec+0x101/0x170 fs/ext4/extents.c:4850
 ext4_end_io_end fs/ext4/page-io.c:186 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:259 [inline]
 ext4_end_io_rsv_work+0x36c/0x6f0 fs/ext4/page-io.c:273
 process_one_work kernel/workqueue.c:2630 [inline]
 process_scheduled_works+0x90f/0x1420 kernel/workqueue.c:2703
 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2784
 kthread+0x2d3/0x370 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001d09000 refcount:1 mapcount:1 mapping:0000000000000000 index:0x7fe1173d0 pfn:0x74240
memcg:ffff888016262000
anon flags: 0xfff000000a0028(uptodate|lru|mappedtodisk|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff000000a0008 ffffea0001d08fc8 ffffea0001d09048 ffff888075b49221
raw: 00000000000001ea 0000000000000000 00000001ffffffff ffff888016262000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x100cca(GFP_HIGHUSER_MOVABLE), pid 5060, tgid 5060 (syz-executor235), ts 67792474723, free_ts 67791125399
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1544 [inline]
 get_page_from_freelist+0x33ea/0x3570 mm/page_alloc.c:3312
 __alloc_pages+0x255/0x680 mm/page_alloc.c:4568
 alloc_pages_mpol+0x3de/0x640 mm/mempolicy.c:2133
 shmem_alloc_folio mm/shmem.c:1613 [inline]
 shmem_alloc_and_add_folio+0x24f/0xde0 mm/shmem.c:1653
 shmem_get_folio_gfp+0x7c3/0x1ee0 mm/shmem.c:2037
 shmem_get_folio mm/shmem.c:2119 [inline]
 shmem_write_begin+0x170/0x4c0 mm/shmem.c:2702
 generic_perform_write+0x31b/0x630 mm/filemap.c:3918
 shmem_file_write_iter+0xfc/0x120 mm/shmem.c:2878
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x792/0xb20 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1137 [inline]
 free_unref_page_prepare+0x931/0xa60 mm/page_alloc.c:2347
 free_unref_page_list+0x5a0/0x840 mm/page_alloc.c:2533
 release_pages+0x2117/0x2400 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+0x6aa/0x19d0 mm/shmem.c:1004
 shmem_truncate_range mm/shmem.c:1096 [inline]
 shmem_evict_inode+0x29b/0xa60 mm/shmem.c:1224
 evict+0x2a4/0x630 fs/inode.c:664
 __dentry_kill+0x436/0x660 fs/dcache.c:607
 dentry_kill+0xbb/0x290
 dput+0x21e/0x470 fs/dcache.c:913
 __fput+0x60b/0xa10 fs/file_table.c:402
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close fs/open.c:1575 [inline]
 __x64_sys_close+0x7e/0x100 fs/open.c:1575
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
 ffff888074240100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888074240180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888074240200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                         ^
 ffff888074240280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888074240300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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