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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+0xcc0/0xd20 fs/ext4/extents.c:953
Read of size 4 at addr ffff888099b9d408 by task syz-executor.4/3170

CPU: 1 PID: 3170 Comm: syz-executor.4 Not tainted 6.4.0-rc7-syzkaller-00226-ga92b7d26c743 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
 print_report mm/kasan/report.c:462 [inline]
 kasan_report+0x11c/0x130 mm/kasan/report.c:572
 ext4_ext_binsearch fs/ext4/extents.c:837 [inline]
 ext4_find_extent+0xcc0/0xd20 fs/ext4/extents.c:953
 ext4_ext_map_blocks+0x1e1/0x5be0 fs/ext4/extents.c:4102
 ext4_map_blocks+0xa7f/0x18d0 fs/ext4/inode.c:548
 _ext4_get_block+0x241/0x580 fs/ext4/inode.c:779
 ext4_get_block fs/ext4/inode.c:796 [inline]
 __ext4_block_zero_page_range fs/ext4/inode.c:3652 [inline]
 ext4_block_zero_page_range+0x849/0x9e0 fs/ext4/inode.c:3732
 ext4_block_truncate_page fs/ext4/inode.c:3756 [inline]
 ext4_truncate+0xf28/0x1340 fs/ext4/inode.c:4133
 ext4_setattr+0x1b24/0x2880 fs/ext4/inode.c:5460
 notify_change+0xb2c/0x1180 fs/attr.c:483
 do_truncate+0x143/0x200 fs/open.c:66
 do_sys_ftruncate+0x53a/0x770 fs/open.c:194
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f356e08c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f356ed5a168 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f356e1ac120 RCX: 00007f356e08c389
RDX: 0000000000000000 RSI: 0000000002007ffb RDI: 0000000000000005
RBP: 00007f356e0d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd171b2fbf R14: 00007f356ed5a300 R15: 0000000000022000
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000266e740 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x99b9d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 15677, tgid 15676 (syz-executor.1), ts 1471962098067, free_ts 1472273373925
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1731
 prep_new_page mm/page_alloc.c:1738 [inline]
 get_page_from_freelist+0xf41/0x2c00 mm/page_alloc.c:3502
 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4768
 __folio_alloc+0x16/0x40 mm/page_alloc.c:4800
 vma_alloc_folio+0x155/0x890 mm/mempolicy.c:2240
 shmem_alloc_folio+0x119/0x1e0 mm/shmem.c:1579
 shmem_alloc_and_acct_folio+0x15e/0x5d0 mm/shmem.c:1603
 shmem_get_folio_gfp+0x9cc/0x1a80 mm/shmem.c:1948
 shmem_get_folio mm/shmem.c:2079 [inline]
 shmem_write_begin+0x14a/0x380 mm/shmem.c:2573
 generic_perform_write+0x256/0x570 mm/filemap.c:3929
 __generic_file_write_iter+0x2ae/0x500 mm/filemap.c:4057
 generic_file_write_iter+0xe3/0x350 mm/filemap.c:4089
 call_write_iter include/linux/fs.h:1868 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x945/0xd50 fs/read_write.c:584
 ksys_write+0x12b/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 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:1302 [inline]
 free_unref_page_prepare+0x62e/0xcb0 mm/page_alloc.c:2564
 free_unref_page_list+0xe3/0xa70 mm/page_alloc.c:2705
 release_pages+0xcd8/0x1380 mm/swap.c:1042
 __pagevec_release+0x77/0xe0 mm/swap.c:1062
 pagevec_release include/linux/pagevec.h:63 [inline]
 folio_batch_release include/linux/pagevec.h:132 [inline]
 shmem_undo_range+0x583/0x1130 mm/shmem.c:954
 shmem_truncate_range mm/shmem.c:1049 [inline]
 shmem_evict_inode+0x32f/0xb60 mm/shmem.c:1164
 evict+0x2ed/0x6b0 fs/inode.c:665
 iput_final fs/inode.c:1747 [inline]
 iput.part.0+0x50a/0x740 fs/inode.c:1773
 iput+0x5c/0x80 fs/inode.c:1763
 dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
 __dentry_kill+0x3c0/0x640 fs/dcache.c:607
 dentry_kill fs/dcache.c:733 [inline]
 dput+0x865/0xe10 fs/dcache.c:913
 __fput+0x3cc/0xa90 fs/file_table.c:329
 task_work_run+0x16f/0x270 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297

Memory state around the buggy address:
 ffff888099b9d300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888099b9d380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888099b9d400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff888099b9d480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888099b9d500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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