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BUG: KASAN: use-after-free in sysv_new_inode+0xd8c/0xf04 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff0000f7c581ce by task syz.2.53/4822

CPU: 0 PID: 4822 Comm: syz.2.53 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0x100 mm/kasan/report.c:524
 __asan_report_load2_noabort+0x2c/0x38 mm/kasan/report_generic.c:349
 sysv_new_inode+0xd8c/0xf04 fs/sysv/ialloc.c:153
 sysv_mknod+0x5c/0x100 fs/sysv/namei.c:53
 sysv_create+0x38/0x4c fs/sysv/namei.c:67
 lookup_open fs/namei.c:3490 [inline]
 open_last_lookups fs/namei.c:3558 [inline]
 path_openat+0x112c/0x2680 fs/namei.c:3788
 do_filp_open+0x174/0x344 fs/namei.c:3818
 do_sys_openat2+0x128/0x3d8 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __arm64_sys_openat+0x120/0x154 fs/open.c:1347
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:00000000c8dc5414 refcount:1 mapcount:0 mapping:00000000521f62a4 index:0xc3e pfn:0x137c58
memcg:ffff0000dd368000
aops:shmem_aops ino:417 dentry name(?):"memfd:syzkaller"
flags: 0x5ffd8000008001e(referenced|uptodate|dirty|lru|swapbacked|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffd8000008001e fffffc0003df1688 fffffc0003df1c88 ffff0000f6901008
raw: 0000000000000c3e 0000000000000000 00000001ffffffff ffff0000dd368000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f7c58080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000f7c58100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000f7c58180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                              ^
 ffff0000f7c58200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000f7c58280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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