================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x319b/0x4070 kernel/locking/lockdep.c:3224 Read of size 8 at addr ffff8801a4f6d5a0 by task syz-executor0/6079 CPU: 1 PID: 6079 Comm: syz-executor0 Not tainted 4.9.113-g47bbcd6 #62 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 IPv6: ADDRCONF(NETDEV_CHANGE): syz_tun: link becomes ready ffff8801add6fa60 ffffffff81eb32a9 ffffea000693da00 ffff8801a4f6d5a0 0000000000000000 ffff8801a4f6d5a0 0000000000000000 ffff8801add6fa98 ffffffff81567bd9 ffff8801a4f6d5a0 0000000000000008 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x6c/0x234 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 [] __lock_acquire+0x319b/0x4070 kernel/locking/lockdep.c:3224 [] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 [] __raw_spin_lock_bh include/linux/spinlock_api_smp.h:137 [inline] [] _raw_spin_lock_bh+0x3a/0x50 kernel/locking/spinlock.c:175 [] spin_lock_bh include/linux/spinlock.h:307 [inline] [] lock_sock_nested+0x43/0x120 net/core/sock.c:2503 [] lock_sock include/net/sock.h:1404 [inline] [] pppol2tp_release+0x50/0x2e0 net/l2tp/l2tp_ppp.c:476 [] sock_release+0x96/0x1c0 net/socket.c:599 [] sock_close+0x16/0x20 net/socket.c:1046 [] __fput+0x263/0x700 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10c/0x180 kernel/task_work.c:116 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161 [] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:260 [inline] [] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 6114: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:609 __kmalloc+0x11d/0x300 mm/slub.c:3741 kmalloc include/linux/slab.h:495 [inline] sk_prot_alloc+0x17e/0x290 net/core/sock.c:1338 sk_alloc+0x3a/0x3a0 net/core/sock.c:1394 pppol2tp_create+0x33/0x1f0 net/l2tp/l2tp_ppp.c:534 pppox_create+0xf6/0x210 drivers/net/ppp/pppox.c:121 __sock_create+0x2ef/0x5f0 net/socket.c:1182 sock_create net/socket.c:1222 [inline] SYSC_socket net/socket.c:1252 [inline] SyS_socket+0xf0/0x1b0 net/socket.c:1232 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 6079: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kfree+0xfb/0x310 mm/slub.c:3878 sk_prot_free net/core/sock.c:1377 [inline] __sk_destruct+0x46f/0x590 net/core/sock.c:1455 sk_destruct+0x63/0x80 net/core/sock.c:1463 __sk_free+0x4f/0x220 net/core/sock.c:1471 sk_free+0x2b/0x40 net/core/sock.c:1482 sock_put include/net/sock.h:1588 [inline] pppol2tp_session_sock_put+0x5a/0x70 net/l2tp/l2tp_ppp.c:271 l2tp_tunnel_closeall+0x268/0x350 net/l2tp/l2tp_core.c:1371 l2tp_udp_encap_destroy+0x87/0xe0 net/l2tp/l2tp_core.c:1394 udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1336 sk_common_release+0x6d/0x300 net/core/sock.c:2727 udp_lib_close+0x15/0x20 include/net/udp.h:203 inet_release+0xff/0x1d0 net/ipv4/af_inet.c:434 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:440 sock_release+0x96/0x1c0 net/socket.c:599 sock_close+0x16/0x20 net/socket.c:1046 __fput+0x263/0x700 fs/file_table.c:208 ____fput+0x15/0x20 fs/file_table.c:244 task_work_run+0x10c/0x180 kernel/task_work.c:116 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline] syscall_return_slowpath arch/x86/entry/common.c:260 [inline] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801a4f6d500 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 160 bytes inside of 2048-byte region [ffff8801a4f6d500, ffff8801a4f6dd00) The buggy address belongs to the page: page:ffffea000693da00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x8000000000004080(slab|head) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801a4f6d480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801a4f6d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801a4f6d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801a4f6d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801a4f6d680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================