ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
==================================================================
BUG: KASAN: use-after-free in ocfs2_find_victim_chain fs/ocfs2/suballoc.c:1447 [inline]
BUG: KASAN: use-after-free in ocfs2_claim_suballoc_bits+0x8b2/0x2450 fs/ocfs2/suballoc.c:1996
Read of size 4 at addr ffff888055055000 by task syz.2.88/6400

CPU: 0 UID: 0 PID: 6400 Comm: syz.2.88 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 ocfs2_find_victim_chain fs/ocfs2/suballoc.c:1447 [inline]
 ocfs2_claim_suballoc_bits+0x8b2/0x2450 fs/ocfs2/suballoc.c:1996
 ocfs2_claim_new_inode+0x332/0x7a0 fs/ocfs2/suballoc.c:2292
 ocfs2_mknod_locked+0x100/0x250 fs/ocfs2/namei.c:637
 ocfs2_symlink+0x120e/0x23e0 fs/ocfs2/namei.c:1952
 vfs_symlink+0x143/0x2f0 fs/namei.c:4817
 do_symlinkat+0x1b1/0x3f0 fs/namei.c:4843
 __do_sys_symlink fs/namei.c:4864 [inline]
 __se_sys_symlink fs/namei.c:4862 [inline]
 __x64_sys_symlink+0x7a/0x90 fs/namei.c:4862
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff44118eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff442078038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007ff4413e5fa0 RCX: 00007ff44118eec9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000200000000580
RBP: 00007ff441211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff4413e6038 R14: 00007ff4413e5fa0 R15: 00007fff2a4cdcd8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x272 pfn:0x55055
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001461d88 ffffea00014ecc08 0000000000000000
raw: 0000000000000272 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 6367, tgid 6365 (syz.4.82), ts 106242627218, free_ts 109137339420
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435
 shmem_alloc_folio mm/shmem.c:1871 [inline]
 shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1910
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2533
 shmem_get_folio mm/shmem.c:2639 [inline]
 shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3289
 generic_perform_write+0x2c5/0x900 mm/filemap.c:4242
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3464
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5879 tgid 5879 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963
 folios_put_refs+0x584/0x670 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1120
 shmem_truncate_range mm/shmem.c:1232 [inline]
 shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360
 evict+0x504/0x9c0 fs/inode.c:810
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 dput+0x19f/0x2b0 fs/dcache.c:911
 __fput+0x68e/0xa70 fs/file_table.c:476
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888055054f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888055054f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888055055000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888055055080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888055055100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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