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BUG: KASAN: use-after-free in sysv_new_inode+0xfd3/0x1170 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88805790d1ce by task syz-executor.4/9884

CPU: 1 PID: 9884 Comm: syz-executor.4 Not tainted 6.10.0-rc2-next-20240607-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:91 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:117
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 sysv_new_inode+0xfd3/0x1170 fs/sysv/ialloc.c:153
 sysv_mknod+0x4e/0xe0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3516 [inline]
 open_last_lookups fs/namei.c:3585 [inline]
 path_openat+0x1425/0x3280 fs/namei.c:3815
 do_filp_open+0x235/0x490 fs/namei.c:3845
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1409
 do_sys_open fs/open.c:1424 [inline]
 __do_sys_openat fs/open.c:1440 [inline]
 __se_sys_openat fs/open.c:1435 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1435
 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: 0033:0x7f124b67cf69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f124c45b0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f124b7b3f80 RCX: 00007f124b67cf69
RDX: 000000000000275a RSI: 0000000020000040 RDI: ffffffffffffff9c
RBP: 00007f124b6da6fe R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f124b7b3f80 R15: 00007ffebe09e648
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2468 pfn:0x5790d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000002468 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 16012, tgid 16011 (syz-executor.4), ts 1073575940970, free_ts 1074951310017
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1470
 prep_new_page mm/page_alloc.c:1478 [inline]
 get_page_from_freelist+0x2cbd/0x2d70 mm/page_alloc.c:3457
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4715
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263
 folio_alloc_mpol_noprof+0x36/0x50 mm/mempolicy.c:2281
 shmem_alloc_folio mm/shmem.c:1723 [inline]
 shmem_alloc_and_add_folio+0x2ce/0x14e0 mm/shmem.c:1783
 shmem_get_folio_gfp+0xa22/0x2660 mm/shmem.c:2189
 shmem_get_folio mm/shmem.c:2294 [inline]
 shmem_write_begin+0x170/0x4d0 mm/shmem.c:2899
 generic_perform_write+0x322/0x640 mm/filemap.c:4016
 shmem_file_write_iter+0xfc/0x120 mm/shmem.c:3075
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 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
page last free pid 16012 tgid 16011 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1089 [inline]
 free_unref_folios+0x103a/0x1b00 mm/page_alloc.c:2669
 folios_put_refs+0x76e/0x860 mm/swap.c:1020
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x6de/0x1df0 mm/shmem.c:1013
 shmem_truncate_range mm/shmem.c:1122 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1250
 evict+0x2a8/0x630 fs/inode.c:667
 __dentry_kill+0x20d/0x630 fs/dcache.c:603
 dput+0x19f/0x2b0 fs/dcache.c:845
 __fput+0x68c/0x8b0 fs/file_table.c:430
 __do_sys_close fs/open.c:1559 [inline]
 __se_sys_close fs/open.c:1544 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1544
 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

Memory state around the buggy address:
 ffff88805790d080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805790d100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805790d180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88805790d200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805790d280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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