syzbot

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BUG: KASAN: use-after-free in sysv_new_inode+0xfc7/0x1160 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff888068a0d1ce by task syz-executor410/5916

CPU: 1 UID: 0 PID: 5916 Comm: syz-executor410 Not tainted 6.13.0-rc3-next-20241220-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 sysv_new_inode+0xfc7/0x1160 fs/sysv/ialloc.c:153
 sysv_mknod+0x4e/0xe0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3649 [inline]
 open_last_lookups fs/namei.c:3748 [inline]
 path_openat+0x192f/0x3580 fs/namei.c:3984
 do_filp_open+0x27f/0x4e0 fs/namei.c:4014
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1427
 do_sys_open fs/open.c:1442 [inline]
 __do_sys_openat fs/open.c:1458 [inline]
 __se_sys_openat fs/open.c:1453 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1453
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1e9ef8e3e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 1f 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:00007f1e9e734168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1e9f01f488 RCX: 00007f1e9ef8e3e9
RDX: 000000000000275a RSI: 00000000200000c0 RDI: 00000000ffffff9c
RBP: 00007f1e9f01f480 R08: 00007f1e9e7346c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1e9f01f48c
R13: 000000000000000b R14: 00007ffc79735830 R15: 00007ffc79735918
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x745a6 pfn:0x68a0d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 00000000000745a6 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 5908, tgid 5907 (syz-executor410), ts 337426589322, free_ts 386898476646
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4754
 alloc_pages_mpol+0x30e/0x550 mm/mempolicy.c:2270
 alloc_frozen_pages_noprof mm/mempolicy.c:2340 [inline]
 alloc_pages_noprof+0x121/0x190 mm/mempolicy.c:2360
 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2370
 filemap_alloc_folio_noprof+0xe1/0x540 mm/filemap.c:1010
 do_read_cache_folio+0x2fd/0x5b0 mm/filemap.c:3855
 read_mapping_folio include/linux/pagemap.h:1032 [inline]
 dir_get_folio fs/sysv/dir.c:64 [inline]
 sysv_find_entry+0x16c/0x590 fs/sysv/dir.c:154
 sysv_inode_by_name+0x98/0x2a0 fs/sysv/dir.c:370
 sysv_lookup+0x6b/0xe0 fs/sysv/namei.c:38
 lookup_open fs/namei.c:3627 [inline]
 open_last_lookups fs/namei.c:3748 [inline]
 path_openat+0x11a7/0x3580 fs/namei.c:3984
 do_filp_open+0x27f/0x4e0 fs/namei.c:4014
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1427
 do_sys_open fs/open.c:1442 [inline]
 __do_sys_openat fs/open.c:1458 [inline]
 __se_sys_openat fs/open.c:1453 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1453
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
page last free pid 5851 tgid 5851 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_folios+0xe40/0x18b0 mm/page_alloc.c:2707
 folios_put_refs+0x76c/0x860 mm/swap.c:990
 folio_batch_release include/linux/pagevec.h:101 [inline]
 truncate_inode_pages_range+0x460/0x10e0 mm/truncate.c:330
 sysv_evict_inode+0x2b/0x110 fs/sysv/inode.c:289
 evict+0x4e8/0x9a0 fs/inode.c:796
 __dentry_kill+0x20d/0x630 fs/dcache.c:625
 dput+0x19f/0x2b0 fs/dcache.c:867
 shrink_dcache_for_umount+0xb4/0x180 fs/dcache.c:1577
 generic_shutdown_super+0x6a/0x2d0 fs/super.c:620
 kill_block_super+0x44/0x90 fs/super.c:1710
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1414
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888068a0d080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068a0d100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888068a0d180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff888068a0d200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888068a0d280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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