syzbot

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BUG: KASAN: use-after-free in sysv_new_inode+0xd24/0xe9c fs/sysv/ialloc.c:153
Read of size 2 at addr ffff0000ddb431ce by task syz-executor314/6306

CPU: 1 PID: 6306 Comm: syz-executor314 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:317
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x198/0x538 mm/kasan/report.c:488
 kasan_report+0xd8/0x138 mm/kasan/report.c:601
 __asan_report_load2_noabort+0x20/0x2c mm/kasan/report_generic.c:379
 sysv_new_inode+0xd24/0xe9c 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:3497 [inline]
 open_last_lookups fs/namei.c:3566 [inline]
 path_openat+0xfb4/0x2830 fs/namei.c:3796
 do_filp_open+0x1bc/0x3cc fs/namei.c:3826
 do_sys_openat2+0x124/0x1b8 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_openat fs/open.c:1437 [inline]
 __se_sys_openat fs/open.c:1432 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1432
 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x11db43
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 05ffc00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ddb43080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000ddb43100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000ddb43180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff0000ddb43200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000ddb43280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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