================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x3c66/0x5270 kernel/locking/lockdep.c:3092 Read of size 8 at addr ffff8800ba0f11a0 by task syz-executor0/14741 CPU: 1 PID: 14741 Comm: syz-executor0 Not tainted 4.4.140-g789274d #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 919019880910498a ffff8800ad17fa30 ffffffff81e0e08d ffffea0002e83c00 ffff8800ba0f11a0 0000000000000000 ffff8800ba0f11a0 0000000000000000 ffff8800ad17fa68 ffffffff81515a56 ffff8800ba0f11a0 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_address_description+0x6c/0x216 mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429 [] __lock_acquire+0x3c66/0x5270 kernel/locking/lockdep.c:3092 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __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:2451 [] lock_sock include/net/sock.h:1493 [inline] [] pppol2tp_release+0x50/0x310 net/l2tp/l2tp_ppp.c:493 [] sock_release+0x96/0x1c0 net/socket.c:586 [] sock_close+0x16/0x20 net/socket.c:1037 [] __fput+0x235/0x6f0 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10f/0x190 kernel/task_work.c:115 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252 [] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:348 [inline] [] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline] [] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 Allocated by task 14746: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616 [] __kmalloc+0x124/0x310 mm/slub.c:3613 [] kmalloc include/linux/slab.h:481 [inline] [] sk_prot_alloc+0x204/0x300 net/core/sock.c:1354 [] sk_alloc+0x3a/0x3a0 net/core/sock.c:1419 [] pppol2tp_create+0x33/0x1f0 net/l2tp/l2tp_ppp.c:551 [] pppox_create+0xf6/0x200 drivers/net/ppp/pppox.c:121 [] __sock_create+0x2f0/0x5f0 net/socket.c:1177 [] sock_create net/socket.c:1217 [inline] [] SYSC_socket net/socket.c:1247 [inline] [] SyS_socket+0xf0/0x1b0 net/socket.c:1227 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 Freed by task 14741: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589 [] slab_free_hook mm/slub.c:1383 [inline] [] slab_free_freelist_hook mm/slub.c:1405 [inline] [] slab_free mm/slub.c:2859 [inline] [] kfree+0xf4/0x310 mm/slub.c:3749 [] sk_prot_free net/core/sock.c:1391 [inline] [] sk_destruct+0x407/0x4c0 net/core/sock.c:1472 [] __sk_free+0x4f/0x220 net/core/sock.c:1480 [] sk_free+0x30/0x40 net/core/sock.c:1491 [] sock_put include/net/sock.h:1639 [inline] [] pppol2tp_session_sock_put+0x5f/0x70 net/l2tp/l2tp_ppp.c:286 [] l2tp_tunnel_closeall+0x23c/0x350 net/l2tp/l2tp_core.c:1277 [] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300 [] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421 [] sk_common_release+0x6d/0x300 net/core/sock.c:2680 [] udp_lib_close+0x15/0x20 include/net/udp.h:190 [] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435 [] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424 [] sock_release+0x96/0x1c0 net/socket.c:586 [] sock_close+0x16/0x20 net/socket.c:1037 [] __fput+0x235/0x6f0 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10f/0x190 kernel/task_work.c:115 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252 [] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:348 [inline] [] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline] [] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 The buggy address belongs to the object at ffff8800ba0f1100 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 160 bytes inside of 2048-byte region [ffff8800ba0f1100, ffff8800ba0f1900) The buggy address belongs to the page: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:973 lock_accessed kernel/locking/lockdep.c:973 [inline]() WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:973 __bfs+0x2aa/0x5f0 kernel/locking/lockdep.c:1040()