========================= WARNING: held lock freed! 4.14.138 #34 Not tainted ------------------------- syz-executor.5/14655 is freeing memory ffff88806bc06b80-ffff88806bc0737f, with a lock still held there! (sk_lock-AF_PPPOX){+.+.}, at: [] lock_sock include/net/sock.h:1462 [inline] (sk_lock-AF_PPPOX){+.+.}, at: [] pppol2tp_release+0x4e/0x300 net/l2tp/l2tp_ppp.c:476 2 locks held by syz-executor.5/14655: #0: (&sb->s_type->i_mutex_key#11){+.+.}, at: [] inode_lock include/linux/fs.h:718 [inline] #0: (&sb->s_type->i_mutex_key#11){+.+.}, at: [] __sock_release+0x89/0x2b0 net/socket.c:601 #1: (sk_lock-AF_PPPOX){+.+.}, at: [] lock_sock include/net/sock.h:1462 [inline] #1: (sk_lock-AF_PPPOX){+.+.}, at: [] pppol2tp_release+0x4e/0x300 net/l2tp/l2tp_ppp.c:476 stack backtrace: CPU: 1 PID: 14655 Comm: syz-executor.5 Not tainted 4.14.138 #34 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+0x138/0x19c lib/dump_stack.c:53 print_freed_lock_bug kernel/locking/lockdep.c:4456 [inline] debug_check_no_locks_freed.cold+0x9d/0xa9 kernel/locking/lockdep.c:4489 kfree+0xb1/0x270 mm/slab.c:3812 sk_prot_free net/core/sock.c:1504 [inline] __sk_destruct+0x493/0x5d0 net/core/sock.c:1583 sk_destruct+0x67/0x80 net/core/sock.c:1591 __sk_free+0x54/0x230 net/core/sock.c:1599 sk_free+0x35/0x40 net/core/sock.c:1610 sock_put include/net/sock.h:1653 [inline] pppol2tp_release+0x27d/0x300 net/l2tp/l2tp_ppp.c:493 __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 RIP: 0033:0x413511 RSP: 002b:00007ffc152d6900 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000413511 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000005 RBP: 0000000000000000 R08: ffffffffffffffff R09: ffffffffffffffff R10: 00007ffc152d69e0 R11: 0000000000000293 R12: 000000000075bfc8 R13: 00000000000475c2 R14: 0000000000760c10 R15: ffffffffffffffff ================================================================== BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] BUG: KASAN: use-after-free in do_raw_spin_lock+0x1eb/0x230 kernel/locking/spinlock_debug.c:112 Read of size 4 at addr ffff88806bc06c0c by task syz-executor.5/14655 CPU: 1 PID: 14655 Comm: syz-executor.5 Not tainted 4.14.138 #34 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+0x138/0x19c 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 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] do_raw_spin_lock+0x1eb/0x230 kernel/locking/spinlock_debug.c:112 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline] _raw_spin_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:176 spin_lock_bh include/linux/spinlock.h:322 [inline] release_sock+0x20/0x1b0 net/core/sock.c:2772 pppol2tp_release+0x22b/0x300 net/l2tp/l2tp_ppp.c:495 __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 RIP: 0033:0x413511 RSP: 002b:00007ffc152d6900 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000413511 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000005 RBP: 0000000000000000 R08: ffffffffffffffff R09: ffffffffffffffff R10: 00007ffc152d69e0 R11: 0000000000000293 R12: 000000000075bfc8 R13: 00000000000475c2 R14: 0000000000760c10 R15: ffffffffffffffff Allocated by task 14664: 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 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15d/0x7a0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] sk_prot_alloc+0x171/0x2a0 net/core/sock.c:1467 sk_alloc+0x39/0xd70 net/core/sock.c:1521 pppol2tp_create+0x32/0x1f0 net/l2tp/l2tp_ppp.c:534 pppox_create+0xf7/0x210 drivers/net/ppp/pppox.c:134 __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 14655: 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] kfree+0xcc/0x270 mm/slab.c:3815 sk_prot_free net/core/sock.c:1504 [inline] __sk_destruct+0x493/0x5d0 net/core/sock.c:1583 sk_destruct+0x67/0x80 net/core/sock.c:1591 __sk_free+0x54/0x230 net/core/sock.c:1599 sk_free+0x35/0x40 net/core/sock.c:1610 sock_put include/net/sock.h:1653 [inline] pppol2tp_release+0x27d/0x300 net/l2tp/l2tp_ppp.c:493 __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 ffff88806bc06b80 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 140 bytes inside of 2048-byte region [ffff88806bc06b80, ffff88806bc07380) The buggy address belongs to the page: page:ffffea0001af0180 count:1 mapcount:0 mapping:ffff88806bc06300 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffff88806bc06300 0000000000000000 0000000100000003 raw: ffffea0001be2120 ffffea0001bf2020 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88806bc06b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88806bc06b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88806bc06c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88806bc06c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88806bc06d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================