================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123 Read of size 4 at addr ffff88805d81f7c0 by task syz-executor.5/11474 CPU: 1 PID: 11474 Comm: syz-executor.5 Not tainted 5.3.0-rc2+ #90 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:612 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192 __kasan_check_read+0x11/0x20 mm/kasan/common.c:92 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123 refcount_inc_checked+0x17/0x70 lib/refcount.c:156 sock_hold include/net/sock.h:649 [inline] sk_add_node include/net/sock.h:701 [inline] nr_insert_socket+0x2d/0xe0 net/netrom/af_netrom.c:137 nr_rx_frame+0x1605/0x1e73 net/netrom/af_netrom.c:1023 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828 RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:95 Code: 25 b4 12 19 09 41 bc f4 ff ff ff e8 6d a0 e9 ff 48 c7 05 9e 12 19 09 00 00 00 00 e9 77 e9 ff ff 90 90 90 90 90 90 90 90 90 55 <48> 89 e5 65 48 8b 04 25 40 fe 01 00 65 8b 15 84 5e 8f 7e 81 e2 00 RSP: 0018:ffff88805ead7580 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: ffffed10110cb000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffea0002219600 RBP: ffff88805ead75c8 R08: 1ffffd40004432c6 R09: ffffed10110cb000 R10: fffff940004432c6 R11: ffffea0002219637 R12: 0000000000000001 R13: ffffea0002219600 R14: ffffea0002219634 R15: 0000000000000001 post_alloc_hook mm/page_alloc.c:2146 [inline] prep_new_page+0x121/0x330 mm/page_alloc.c:2153 get_page_from_freelist+0x1c35/0x39d0 mm/page_alloc.c:3691 __alloc_pages_nodemask+0x2d0/0x8f0 mm/page_alloc.c:4725 alloc_pages_current+0x107/0x210 mm/mempolicy.c:2133 alloc_pages include/linux/gfp.h:509 [inline] __get_free_pages+0xc/0x40 mm/page_alloc.c:4769 mmu_topup_memory_cache_page arch/x86/kvm/mmu.c:1030 [inline] mmu_topup_memory_caches+0x1e1/0x490 arch/x86/kvm/mmu.c:1052 kvm_mmu_load+0x21/0x12f0 arch/x86/kvm/mmu.c:5105 kvm_mmu_reload arch/x86/kvm/mmu.h:81 [inline] vcpu_enter_guest+0x3dc3/0x5eb0 arch/x86/kvm/x86.c:7939 vcpu_run arch/x86/kvm/x86.c:8151 [inline] kvm_arch_vcpu_ioctl_run+0x464/0x1790 arch/x86/kvm/x86.c:8359 kvm_vcpu_ioctl+0x4dc/0xfc0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2754 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f56fe06bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000007 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f56fe06c6d4 R13: 00000000004c2bcf R14: 00000000004d6150 R15: 00000000ffffffff Allocated by task 11474: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:487 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x163/0x770 mm/slab.c:3664 kmalloc include/linux/slab.h:557 [inline] sk_prot_alloc+0x23a/0x310 net/core/sock.c:1603 sk_alloc+0x39/0xf70 net/core/sock.c:1657 nr_make_new net/netrom/af_netrom.c:476 [inline] nr_rx_frame+0x733/0x1e73 net/netrom/af_netrom.c:959 nr_loopback_timer+0x7b/0x170 net/netrom/nr_loopback.c:59 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __do_softirq+0x262/0x98c kernel/softirq.c:292 Freed by task 11486: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __cache_free mm/slab.c:3425 [inline] kfree+0x10a/0x2c0 mm/slab.c:3756 sk_prot_free net/core/sock.c:1640 [inline] __sk_destruct+0x4f7/0x6e0 net/core/sock.c:1726 sk_destruct+0x86/0xa0 net/core/sock.c:1734 __sk_free+0xfb/0x360 net/core/sock.c:1745 sk_free+0x42/0x50 net/core/sock.c:1756 sock_put include/net/sock.h:1725 [inline] sock_efree+0x61/0x80 net/core/sock.c:2042 skb_release_head_state+0xeb/0x250 net/core/skbuff.c:652 skb_release_all+0x16/0x60 net/core/skbuff.c:663 __kfree_skb net/core/skbuff.c:679 [inline] kfree_skb net/core/skbuff.c:697 [inline] kfree_skb+0x101/0x3c0 net/core/skbuff.c:691 nr_accept+0x56e/0x700 net/netrom/af_netrom.c:819 __sys_accept4+0x34e/0x6a0 net/socket.c:1754 __do_sys_accept4 net/socket.c:1789 [inline] __se_sys_accept4 net/socket.c:1786 [inline] __x64_sys_accept4+0x97/0xf0 net/socket.c:1786 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88805d81f740 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff88805d81f740, ffff88805d81ff40) The buggy address belongs to the page: page:ffffea0001760780 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea000177bf08 ffffea0002664c88 ffff8880aa400e00 raw: 0000000000000000 ffff88805d81e640 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88805d81f680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88805d81f700: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff88805d81f780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805d81f800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805d81f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================