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BUG: KASAN: use-after-free in ext4_ext_rm_leaf fs/ext4/extents.c:2630 [inline]
BUG: KASAN: use-after-free in ext4_ext_remove_space+0x3170/0x4280 fs/ext4/extents.c:2964
Read of size 4 at addr ffff88801fcf9c18 by task syz.0.0/5324

CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_ext_rm_leaf fs/ext4/extents.c:2630 [inline]
 ext4_ext_remove_space+0x3170/0x4280 fs/ext4/extents.c:2964
 ext4_ext_truncate+0x17e/0x2f0 fs/ext4/extents.c:4537
 ext4_truncate+0xb63/0x13b0 fs/ext4/inode.c:4564
 ext4_evict_inode+0x863/0xeb0 fs/ext4/inode.c:262
 evict+0x61e/0xb10 fs/inode.c:846
 __dentry_kill+0x1a2/0x5e0 fs/dcache.c:670
 finish_dput+0xc9/0x480 fs/dcache.c:879
 __fput+0x691/0xa70 fs/file_table.c:477
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f493999c799
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:00007ffe07ab8698 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffe07ab8780 RCX: 00007f493999c799
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000014973 R08: 0000000000000001 R09: 0000000000000000
R10: 00007f49397ff03c R11: 0000000000000246 R12: 00007ffe07ab87c0
R13: 00007f4939c15fac R14: 0000000000014ab0 R15: 00007f4939c15fa0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1e pfn:0x1fcf9
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 000000000000001e 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 0x152c4a(GFP_NOFS|__GFP_HIGHMEM|__GFP_MOVABLE|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 1, tgid 1 (init), ts 30912906097, free_ts 81303817116
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
 alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline]
 alloc_pages_noprof+0xa8/0x190 mm/mempolicy.c:2575
 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2585
 filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1013
 ractl_alloc_folio mm/readahead.c:189 [inline]
 page_cache_ra_unbounded+0x39b/0xa50 mm/readahead.c:277
 do_page_cache_ra mm/readahead.c:334 [inline]
 page_cache_ra_order+0xaf2/0xeb0 mm/readahead.c:538
 filemap_readahead mm/filemap.c:2663 [inline]
 filemap_get_pages+0x897/0x1f10 mm/filemap.c:2709
 filemap_read+0x447/0x1230 mm/filemap.c:2805
 __kernel_read+0x504/0x9b0 fs/read_write.c:532
 integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline]
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline]
 ima_calc_file_hash+0x12c3/0x17f0 security/integrity/ima/ima_crypto.c:568
 ima_collect_measurement+0x48b/0x930 security/integrity/ima/ima_api.c:295
 process_measurement+0x12cd/0x1c80 security/integrity/ima/ima_main.c:407
page last free pid 77 tgid 77 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040
 shrink_folio_list+0x4a6b/0x5290 mm/vmscan.c:1610
 evict_folios+0x4795/0x5880 mm/vmscan.c:4718
 try_to_shrink_lruvec+0xb62/0xfa0 mm/vmscan.c:4881
 shrink_one+0x25c/0x710 mm/vmscan.c:4926
 shrink_many mm/vmscan.c:4989 [inline]
 lru_gen_shrink_node mm/vmscan.c:5067 [inline]
 shrink_node+0x3197/0x3a90 mm/vmscan.c:6047
 kswapd_shrink_node mm/vmscan.c:6894 [inline]
 balance_pgdat mm/vmscan.c:7070 [inline]
 kswapd+0x1742/0x2e10 mm/vmscan.c:7343
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88801fcf9b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88801fcf9b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88801fcf9c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff88801fcf9c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88801fcf9d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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