loop3: rw=0, sector=6491536, nr_sectors = 2 limit=128
Buffer I/O error on dev loop3, logical block 3245768, async page read
==================================================================
BUG: KASAN: use-after-free in sysv_new_inode+0xd8c/0xf04 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff0000fd9401ce by task syz.3.79/4839

CPU: 0 PID: 4839 Comm: syz.3.79 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
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
 vfs_mknod+0x3c4/0x44c fs/namei.c:3985
 do_mknodat+0x320/0x54c fs/namei.c:-1
 __do_sys_mknodat fs/namei.c:4063 [inline]
 __se_sys_mknodat fs/namei.c:4060 [inline]
 __arm64_sys_mknodat+0xb0/0xcc fs/namei.c:4060
 __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:00000000e339e8be refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x13d940
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003922008 fffffc0003eaf008 0000000000000000
raw: 0000000000000001 0000000000000006 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000fd940080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000fd940100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000fd940180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff0000fd940200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000fd940280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
syz.3.79: attempt to access beyond end of device
loop3: rw=0, sector=6491536, nr_sectors = 2 limit=128
Buffer I/O error on dev loop3, logical block 3245768, async page read
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_block: flc_count > flc_size
sysv_free_inode: inode 0,1,2 or nonexistent inode