VFS: Found a Xenix FS (block size = 1024) on device loop0
syz.0.17: attempt to access beyond end of device
loop0: rw=0, sector=6491536, nr_sectors = 2 limit=128
Buffer I/O error on dev loop0, logical block 3245768, async page read
==================================================================
BUG: KASAN: use-after-free in sysv_new_inode+0x10c5/0x1270 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88806d3c61ce by task syz.0.17/5943
CPU: 1 PID: 5943 Comm: syz.0.17 Not tainted 6.6.97-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xac/0x230 mm/kasan/report.c:475
kasan_report+0x117/0x150 mm/kasan/report.c:588
sysv_new_inode+0x10c5/0x1270 fs/sysv/ialloc.c:153
sysv_mknod+0x4e/0xe0 fs/sysv/namei.c:53
lookup_open fs/namei.c:3488 [inline]
open_last_lookups fs/namei.c:3556 [inline]
path_openat+0x1277/0x3190 fs/namei.c:3786
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_openat fs/open.c:1450 [inline]
__se_sys_openat fs/open.c:1445 [inline]
__x64_sys_openat+0x139/0x160 fs/open.c:1445
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8f6898e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd5b7195e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8f68bb5fa0 RCX: 00007f8f6898e929
RDX: 0000000000101042 RSI: 0000200000000180 RDI: ffffffffffffff9c
RBP: 00007f8f68a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001b6 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8f68bb5fa0 R14: 00007f8f68bb5fa0 R15: 0000000000000004
</TASK>
The buggy address belongs to the physical page:
page:ffffea0001b4f180 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6d3c6
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001b4f0c8 ffffea0001b4fd48 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 5905, tgid 5905 (dhcpcd-run-hook), ts 101055668992, free_ts 101459567536
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
prep_new_page mm/page_alloc.c:1561 [inline]
get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
__alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
__folio_alloc+0x10/0x20 mm/page_alloc.c:4489
vma_alloc_folio+0x47a/0x8f0 mm/mempolicy.c:2242
do_anonymous_page mm/memory.c:4149 [inline]
do_pte_missing mm/memory.c:3686 [inline]
handle_pte_fault mm/memory.c:5025 [inline]
__handle_mm_fault mm/memory.c:5166 [inline]
handle_mm_fault+0x1a38/0x4920 mm/memory.c:5331
do_user_addr_fault+0xad0/0x12e0 arch/x86/mm/fault.c:1324
handle_page_fault arch/x86/mm/fault.c:1465 [inline]
exc_page_fault+0x67/0x110 arch/x86/mm/fault.c:1521
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1154 [inline]
free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
release_pages+0x1fa0/0x2220 mm/swap.c:1022
tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
exit_mmap+0x3f0/0xb50 mm/mmap.c:3311
__mmput+0x118/0x3c0 kernel/fork.c:1355
exit_mm+0x1da/0x2c0 kernel/exit.c:569
do_exit+0x88e/0x23c0 kernel/exit.c:870
do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
__do_sys_exit_group kernel/exit.c:1035 [inline]
__se_sys_exit_group kernel/exit.c:1033 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Memory state around the buggy address:
ffff88806d3c6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806d3c6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806d3c6180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806d3c6200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806d3c6280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================