================================================================== 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+0x295/0x3a0 kernel/locking/spinlock_debug.c:112 Read of size 4 at addr ffff88809f0acf0c by task syz-executor847/10804 CPU: 0 PID: 10804 Comm: syz-executor847 Not tainted 5.3.0-rc1+ #51 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+0x1d8/0x2f8 lib/dump_stack.c:113 print_address_description+0x75/0x5b0 mm/kasan/report.c:351 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:482 kasan_report+0x26/0x50 mm/kasan/common.c:612 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] do_raw_spin_lock+0x295/0x3a0 kernel/locking/spinlock_debug.c:112 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline] _raw_spin_lock_bh+0x40/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] lock_sock_nested+0x45/0x120 net/core/sock.c:2917 lock_sock include/net/sock.h:1522 [inline] nr_getname+0x5b/0x220 net/netrom/af_netrom.c:838 __sys_accept4+0x63a/0x9a0 net/socket.c:1759 __do_sys_accept4 net/socket.c:1789 [inline] __se_sys_accept4 net/socket.c:1786 [inline] __x64_sys_accept4+0x9a/0xb0 net/socket.c:1786 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4480e9 Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 4b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f43bf6ced88 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 RAX: ffffffffffffffda RBX: 00000000006ddc38 RCX: 00000000004480e9 RDX: 0000000000000000 RSI: 0000000020000b00 RDI: 0000000000000004 RBP: 00000000006ddc30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc3c R13: 00007ffd18de174f R14: 00007f43bf6cf9c0 R15: 00000000006ddc3c Allocated by task 0: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:487 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x254/0x340 mm/slab.c:3664 kmalloc include/linux/slab.h:557 [inline] sk_prot_alloc+0xb0/0x290 net/core/sock.c:1603 sk_alloc+0x38/0x950 net/core/sock.c:1657 nr_make_new net/netrom/af_netrom.c:476 [inline] nr_rx_frame+0xabc/0x1e40 net/netrom/af_netrom.c:959 nr_loopback_timer+0x6a/0x140 net/netrom/nr_loopback.c:59 call_timer_fn+0xec/0x200 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers+0x7cd/0x9c0 kernel/time/timer.c:1685 run_timer_softirq+0x4a/0x90 kernel/time/timer.c:1698 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:778 Freed by task 10804: save_stack mm/kasan/common.c:69 [inline] set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __cache_free mm/slab.c:3425 [inline] kfree+0x115/0x200 mm/slab.c:3756 sk_prot_free net/core/sock.c:1640 [inline] __sk_destruct+0x567/0x660 net/core/sock.c:1726 sk_destruct net/core/sock.c:1734 [inline] __sk_free+0x317/0x3e0 net/core/sock.c:1745 sk_free net/core/sock.c:1756 [inline] sock_put include/net/sock.h:1725 [inline] sock_efree+0x60/0x80 net/core/sock.c:2042 skb_release_head_state+0x100/0x220 net/core/skbuff.c:652 skb_release_all net/core/skbuff.c:663 [inline] __kfree_skb+0x25/0x170 net/core/skbuff.c:679 kfree_skb+0x6f/0xb0 net/core/skbuff.c:697 nr_accept+0x4ef/0x650 net/netrom/af_netrom.c:819 __sys_accept4+0x5bc/0x9a0 net/socket.c:1754 __do_sys_accept4 net/socket.c:1789 [inline] __se_sys_accept4 net/socket.c:1786 [inline] __x64_sys_accept4+0x9a/0xb0 net/socket.c:1786 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809f0ace80 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 140 bytes inside of 2048-byte region [ffff88809f0ace80, ffff88809f0ad680) The buggy address belongs to the page: page:ffffea00027c2b00 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002704708 ffffea0002695508 ffff8880aa400e00 raw: 0000000000000000 ffff88809f0ac600 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809f0ace00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809f0ace80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809f0acf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809f0acf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809f0ad000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ ODEBUG: activate not available (active state 0) object type: timer_list hint: nr_t1timer_expiry+0x0/0x400 net/netrom/nr_timer.c:46 WARNING: CPU: 0 PID: 10804 at lib/debugobjects.c:484 debug_print_object lib/debugobjects.c:481 [inline] WARNING: CPU: 0 PID: 10804 at lib/debugobjects.c:484 debug_object_activate+0x33d/0x6f0 lib/debugobjects.c:680 Modules linked in: CPU: 0 PID: 10804 Comm: syz-executor847 Tainted: G B 5.3.0-rc1+ #51 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_print_object lib/debugobjects.c:481 [inline] RIP: 0010:debug_object_activate+0x33d/0x6f0 lib/debugobjects.c:680 Code: f7 e8 f7 01 4a fe 4d 8b 06 48 c7 c7 ca 56 88 88 48 c7 c6 f0 2d a1 88 48 c7 c2 e3 69 81 88 31 c9 49 89 d9 31 c0 e8 63 6d e0 fd <0f> 0b 48 ba 00 00 00 00 00 fc ff df ff 05 65 92 95 05 49 83 c6 20 RSP: 0018:ffff88809633faa8 EFLAGS: 00010046 RAX: a65408733c6cb800 RBX: ffffffff86dc84e0 RCX: ffff8880a8b08440 RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000 RBP: ffff88809633faf0 R08: ffffffff816063f4 R09: ffffed1015d440c2 R10: ffffed1015d440c2 R11: 0000000000000000 R12: ffff8880a10bfd70 R13: 1ffff11014217fae R14: ffffffff88cd9fc0 R15: ffff88809f0ad358 FS: 00007f43bf6cf700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000008c7b1000 CR4: 00000000001406f0 Call Trace: debug_timer_activate kernel/time/timer.c:710 [inline] __mod_timer+0x960/0x16e0 kernel/time/timer.c:1035 mod_timer+0x1f/0x30 kernel/time/timer.c:1096 sk_reset_timer+0x22/0x50 net/core/sock.c:2821 nr_start_t1timer+0x78/0x90 net/netrom/nr_timer.c:52 nr_release+0x238/0x390 net/netrom/af_netrom.c:537 __sock_release net/socket.c:590 [inline] sock_close+0xe1/0x260 net/socket.c:1268 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:163 [inline] prepare_exit_to_usermode+0x459/0x580 arch/x86/entry/common.c:194 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:274 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4480e9 Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 4b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f43bf6ced88 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 RAX: fffffffffffffff2 RBX: 00000000006ddc38 RCX: 00000000004480e9 RDX: 0000000000000000 RSI: 0000000020000b00 RDI: 0000000000000004 RBP: 00000000006ddc30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc3c R13: 00007ffd18de174f R14: 00007f43bf6cf9c0 R15: 00000000006ddc3c irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [] copy_process+0x1589/0x5bc0 kernel/fork.c:1960 softirqs last enabled at (0): [] copy_process+0x15ff/0x5bc0 kernel/fork.c:1963 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace 41aab9a9be4009d5 ]---