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BUG: KASAN: use-after-free in sysv_new_inode+0x107e/0x1210 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88805594f1ce by task syz-executor.2/3811

CPU: 0 PID: 3811 Comm: syz-executor.2 Not tainted 6.1.90-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 sysv_new_inode+0x107e/0x1210 fs/sysv/ialloc.c:153
 sysv_mknod+0x4a/0xe0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3484 [inline]
 open_last_lookups fs/namei.c:3552 [inline]
 path_openat+0x12f1/0x2e60 fs/namei.c:3782
 do_filp_open+0x230/0x480 fs/namei.c:3812
 do_sys_openat2+0x13b/0x500 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_creat fs/open.c:1410 [inline]
 __se_sys_creat fs/open.c:1404 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1404
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6380a7dca9
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:00007f637f5f60c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f6380babf80 RCX: 00007f6380a7dca9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 00007f6380ac947e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f6380babf80 R15: 00007ffe348a9d18
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00015653c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x5594f
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 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 4783, tgid 4782 (syz-executor.0), ts 157586749109, free_ts 158607250042
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513
 prep_new_page mm/page_alloc.c:2520 [inline]
 get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5547
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5579
 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x5a8/0xd50 mm/shmem.c:1613
 shmem_get_folio_gfp+0x13f0/0x3470 mm/shmem.c:1941
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2559
 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3817
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3945
 generic_file_write_iter+0xab/0x310 mm/filemap.c:3977
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7ae/0xba0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1440 [inline]
 free_pcp_prepare mm/page_alloc.c:1490 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3358
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3499
 release_pages+0x2836/0x2b40 mm/swap.c:1055
 __pagevec_release+0x80/0xf0 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x865/0x2390 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x265/0xa60 mm/shmem.c:1171
 evict+0x2a4/0x620 fs/inode.c:666
 __dentry_kill+0x436/0x650 fs/dcache.c:607
 dentry_kill+0xbb/0x290
 dput+0xfb/0x1d0 fs/dcache.c:914
 __fput+0x5e4/0x890 fs/file_table.c:328
 task_work_run+0x246/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87

Memory state around the buggy address:
 ffff88805594f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805594f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805594f180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88805594f200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805594f280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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