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BUG: KASAN: use-after-free in reiserfs_release_objectid+0x527/0x780 fs/reiserfs/objectid.c:165
Read of size 8188 at addr ffff88806de65050 by task syz.0.18/5060

CPU: 1 PID: 5060 Comm: syz.0.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 reiserfs_release_objectid+0x527/0x780 fs/reiserfs/objectid.c:165
 remove_save_link+0x2af/0x3e0 fs/reiserfs/super.c:542
 reiserfs_evict_inode+0x3ae/0x4c0 fs/reiserfs/inode.c:91
 evict+0x4c9/0x8d0 fs/inode.c:647
 __dentry_kill+0x431/0x650 fs/dcache.c:586
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xd8/0x1a0 fs/dcache.c:893
 __fput+0x5ee/0x930 fs/file_table.c:319
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f00ed817ef9
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:00007ffe02dec6b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f00eda84da0 RCX: 00007f00ed817ef9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f00eda84da0 R08: 00007f00eda83038 R09: 0000000000000000
R10: 000000000003fdc0 R11: 0000000000000246 R12: 0000000000017e70
R13: 00007f00eda82fac R14: 0000000000017ccc R15: 00007ffe02dec7c0
 </TASK>

The buggy address belongs to the page:
page:ffffea0001b79940 refcount:2 mapcount:0 mapping:ffff88814088daf0 index:0x10 pfn:0x6de65
memcg:ffff88807b4ec000
aops:def_blk_aops ino:700000
flags: 0xfff00000022036(referenced|uptodate|lru|active|private|mappedtodisk|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000022036 ffffea0001b79908 ffff88802b3b6030 ffff88814088daf0
raw: 0000000000000010 ffff888073a14ae0 00000002ffffffff ffff88807b4ec000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 5061, ts 97170892067, free_ts 97151976263
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
 __page_cache_alloc+0xce/0x440 mm/filemap.c:1022
 pagecache_get_page+0x9b6/0xf10 mm/filemap.c:1940
 find_or_create_page include/linux/pagemap.h:420 [inline]
 grow_dev_page fs/buffer.c:949 [inline]
 grow_buffers fs/buffer.c:1014 [inline]
 __getblk_slow fs/buffer.c:1041 [inline]
 __getblk_gfp+0x247/0xb60 fs/buffer.c:1336
 __bread_gfp+0x28/0x380 fs/buffer.c:1381
 sb_bread include/linux/buffer_head.h:337 [inline]
 read_super_block+0x91/0x7a0 fs/reiserfs/super.c:1606
 reiserfs_fill_super+0x7a6/0x2440 fs/reiserfs/super.c:1968
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x119/0x820 mm/page_alloc.c:3433
 release_pages+0x186c/0x1be0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x176/0x300 mm/mmu_gather.c:338
 unmap_region+0x344/0x3b0 mm/mmap.c:2669
 __do_munmap+0x9f8/0xdf0 mm/mmap.c:2899
 __vm_munmap+0x140/0x240 mm/mmap.c:2952
 __do_sys_munmap mm/mmap.c:2978 [inline]
 __se_sys_munmap mm/mmap.c:2974 [inline]
 __x64_sys_munmap+0x67/0x70 mm/mmap.c:2974
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88806de65f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88806de65f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806de66000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88806de66080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806de66100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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