audit: type=1804 audit(1570692968.211:571): pid=18574 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir066150166/syzkaller.cLh394/607/bus" dev="sda1" ino=17349 res=1 ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:27 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero+0xd3/0xe0 lib/refcount.c:120 Read of size 4 at addr ffff88807fdf1180 by task syz-executor.0/18589 CPU: 0 PID: 18589 Comm: syz-executor.0 Not tainted 4.14.148 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x138/0x197 lib/dump_stack.c:53 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 __read_once_size include/linux/compiler.h:183 [inline] atomic_read arch/x86/include/asm/atomic.h:27 [inline] refcount_inc_not_zero+0xd3/0xe0 lib/refcount.c:120 refcount_inc+0x16/0x40 lib/refcount.c:153 sock_hold include/net/sock.h:619 [inline] l2tp_session_add_to_tunnel net/l2tp/l2tp_core.c:368 [inline] l2tp_session_create+0x118b/0x1600 net/l2tp/l2tp_core.c:1846 audit: type=1804 audit(1570692968.421:572): pid=18589 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.0" name="/root/syzkaller-testdir211399037/syzkaller.cDAvI7/448/bus" dev="sda1" ino=17338 res=1 pppol2tp_connect+0x11bf/0x18b0 net/l2tp/l2tp_ppp.c:721 SYSC_connect+0x1f6/0x2d0 net/socket.c:1655 SyS_connect+0x24/0x30 net/socket.c:1636 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x459a59 RSP: 002b:00007f1612ca5c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a59 RDX: 000000000000002e RSI: 0000000020000000 RDI: 0000000000000006 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1612ca66d4 R13: 00000000004c0006 R14: 00000000004d2298 R15: 00000000ffffffff Allocated by task 18566: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x780 mm/slab.c:3552 sk_prot_alloc+0x67/0x2a0 net/core/sock.c:1461 sk_alloc+0x39/0xd70 net/core/sock.c:1521 inet6_create net/ipv6/af_inet6.c:183 [inline] inet6_create+0x2d8/0xe10 net/ipv6/af_inet6.c:110 __sock_create+0x2f6/0x620 net/socket.c:1275 sock_create net/socket.c:1315 [inline] SYSC_socket net/socket.c:1345 [inline] SyS_socket+0xd3/0x170 net/socket.c:1325 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 18560: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x83/0x2b0 mm/slab.c:3758 sk_prot_free net/core/sock.c:1502 [inline] __sk_destruct+0x3ac/0x580 net/core/sock.c:1581 sk_destruct+0xa4/0xd0 net/core/sock.c:1596 __sk_free+0x54/0x230 net/core/sock.c:1604 sk_free+0x35/0x40 net/core/sock.c:1615 sock_put include/net/sock.h:1653 [inline] l2tp_session_free+0x1b2/0x210 net/l2tp/l2tp_core.c:1709 l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:300 [inline] pppol2tp_session_destruct+0xd8/0x110 net/l2tp/l2tp_ppp.c:460 __sk_destruct+0x4f/0x580 net/core/sock.c:1556 sk_destruct+0xa4/0xd0 net/core/sock.c:1596 __sk_free+0x54/0x230 net/core/sock.c:1604 sk_free+0x35/0x40 net/core/sock.c:1615 sock_put include/net/sock.h:1653 [inline] pppol2tp_release+0x244/0x300 net/l2tp/l2tp_ppp.c:501 __sock_release+0xce/0x2b0 net/socket.c:602 sock_close+0x1b/0x30 net/socket.c:1139 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff88807fdf1100 which belongs to the cache UDPv6 of size 1728 The buggy address is located 128 bytes inside of 1728-byte region [ffff88807fdf1100, ffff88807fdf17c0) The buggy address belongs to the page: page:ffffea0001ff7c40 count:1 mapcount:0 mapping:ffff88807fdf1100 index:0x0 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff88807fdf1100 0000000000000000 0000000100000002 raw: ffffea0002791820 ffffea00026e3ee0 ffff88809be46a80 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88807fdf1080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807fdf1100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807fdf1180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807fdf1200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807fdf1280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================