VFS: Found a Xenix FS (block size = 1024) on device loop0 ================================================================== BUG: KASAN: use-after-free in sysv_new_inode+0x107e/0x1210 fs/sysv/ialloc.c:153 Read of size 2 at addr ffff88807278a1ce by task syz.0.1/4339 CPU: 0 PID: 4339 Comm: syz.0.1 Not tainted 6.1.127-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __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:316 [inline] print_report+0x15f/0x4f0 mm/kasan/report.c:427 kasan_report+0x136/0x160 mm/kasan/report.c:531 sysv_new_inode+0x107e/0x1210 fs/sysv/ialloc.c:153 sysv_mknod+0x4a/0xe0 fs/sysv/namei.c:53 lookup_open fs/namei.c:3482 [inline] open_last_lookups fs/namei.c:3550 [inline] path_openat+0x12f1/0x2e60 fs/namei.c:3780 do_filp_open+0x230/0x480 fs/namei.c:3810 do_sys_openat2+0x13b/0x4f0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1345 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: 0033:0x7f1c0978cd29 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:00007f1c0a525038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1c099a5fa0 RCX: 00007f1c0978cd29 RDX: 0000000000000042 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 00007f1c0980e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1c099a5fa0 R15: 00007ffe884868b8 The buggy address belongs to the physical page: page:ffffea0001c9e280 refcount:2 mapcount:1 mapping:ffff888073ebc288 index:0x659 pfn:0x7278a memcg:ffff888054fea000 aops:shmem_aops ino:403 dentry name(?):"dev/zero" flags: 0xfff80000080016(referenced|uptodate|lru|swapbacked|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff80000080016 ffffea0001c9e248 ffffea0001c9e2c8 ffff888073ebc288 raw: 0000000000000659 0000000000000000 0000000200000000 ffff888054fea000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 4338, tgid 4337 (syz.2.7), ts 85057352842, free_ts 74832960142 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532 prep_new_page mm/page_alloc.c:2539 [inline] get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605 __folio_alloc+0xf/0x30 mm/page_alloc.c:5637 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_fault+0x235/0x9c0 mm/shmem.c:2156 __do_fault+0x136/0x4f0 mm/memory.c:4278 do_read_fault mm/memory.c:4629 [inline] do_fault mm/memory.c:4758 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x3410/0x5340 mm/memory.c:5292 faultin_page mm/gup.c:1009 [inline] __get_user_pages+0x4f3/0x1190 mm/gup.c:1233 populate_vma_page_range+0x217/0x2b0 mm/gup.c:1590 __mm_populate+0x275/0x440 mm/gup.c:1704 mm_populate include/linux/mm.h:2801 [inline] vm_mmap_pgoff+0x22b/0x2d0 mm/util.c:525 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:1459 [inline] free_pcp_prepare mm/page_alloc.c:1509 [inline] free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3525 release_pages+0x24c4/0x27a0 mm/swap.c:1035 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline] tlb_flush_mmu_free mm/mmu_gather.c:254 [inline] tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361 unmap_region+0x29f/0x2f0 mm/mmap.c:2331 do_mas_align_munmap+0xef5/0x15a0 mm/mmap.c:2580 do_mas_munmap+0x246/0x2b0 mm/mmap.c:2638 __vm_munmap+0x268/0x370 mm/mmap.c:2924 __do_sys_munmap mm/mmap.c:2949 [inline] __se_sys_munmap mm/mmap.c:2946 [inline] __x64_sys_munmap+0x5c/0x70 mm/mmap.c:2946 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 Memory state around the buggy address: ffff88807278a080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88807278a100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88807278a180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff88807278a200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88807278a280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================