ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
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BUG: KASAN: use-after-free in ocfs2_find_smallest_chain fs/ocfs2/suballoc.c:413 [inline]
BUG: KASAN: use-after-free in ocfs2_block_group_alloc_contig fs/ocfs2/suballoc.c:430 [inline]
BUG: KASAN: use-after-free in ocfs2_block_group_alloc fs/ocfs2/suballoc.c:699 [inline]
BUG: KASAN: use-after-free in ocfs2_reserve_suballoc_bits+0xdd0/0x4640 fs/ocfs2/suballoc.c:834
Read of size 4 at addr ffff888075770004 by task syz-executor236/5856

CPU: 0 UID: 0 PID: 5856 Comm: syz-executor236 Not tainted 6.16.0-rc1-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 ocfs2_find_smallest_chain fs/ocfs2/suballoc.c:413 [inline]
 ocfs2_block_group_alloc_contig fs/ocfs2/suballoc.c:430 [inline]
 ocfs2_block_group_alloc fs/ocfs2/suballoc.c:699 [inline]
 ocfs2_reserve_suballoc_bits+0xdd0/0x4640 fs/ocfs2/suballoc.c:834
 ocfs2_reserve_new_metadata_blocks+0x403/0x940 fs/ocfs2/suballoc.c:984
 ocfs2_mknod+0xe08/0x2050 fs/ocfs2/namei.c:347
 ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:673
 lookup_open fs/namei.c:3708 [inline]
 open_last_lookups fs/namei.c:3807 [inline]
 path_openat+0x14f4/0x3830 fs/namei.c:4043
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd043ccff89
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 1a 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:00007ffd379440c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd043ccff89
RDX: 0000000000101042 RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 00000000ffffffff R08: 0000000000004465 R09: 00007fd043d24149
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001000000
R13: 00007ffd37944160 R14: 0000200000000040 R15: 0000000000000003
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7fb71c79e pfn:0x75770
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001de7c48 ffffea0001d5dc48 0000000000000000
raw: 00000007fb71c79e 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 5854, tgid 5854 (udevd), ts 105780430290, free_ts 105790998262
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 folio_alloc_mpol_noprof mm/mempolicy.c:2438 [inline]
 vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2473
 folio_prealloc+0x30/0x180 mm/memory.c:-1
 alloc_anon_folio mm/memory.c:5034 [inline]
 do_anonymous_page mm/memory.c:5091 [inline]
 do_pte_missing mm/memory.c:4249 [inline]
 handle_pte_fault mm/memory.c:6089 [inline]
 __handle_mm_fault+0x2c88/0x5620 mm/memory.c:6232
 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6401
 do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
page last free pid 5854 tgid 5854 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 free_unref_folios+0xcd2/0x1570 mm/page_alloc.c:2763
 folios_put_refs+0x559/0x640 mm/swap.c:992
 free_pages_and_swap_cache+0x4be/0x520 mm/swap_state.c:267
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
 tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 vms_clear_ptes+0x42c/0x540 mm/vma.c:1244
 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1286
 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1545
 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1593
 __vm_munmap+0x23b/0x3d0 mm/vma.c:3122
 __do_sys_munmap mm/mmap.c:1084 [inline]
 __se_sys_munmap mm/mmap.c:1081 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1081
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88807576ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807576ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888075770000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888075770080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888075770100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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