vcan0: j1939_tp_rxtimer: 0x000000005420bda0: rx timeout, send abort
==================================================================
BUG: KASAN: use-after-free in atomic_sub_return include/asm-generic/atomic-instrumented.h:159 [inline]
BUG: KASAN: use-after-free in atomic_dec_return include/linux/atomic-fallback.h:455 [inline]
BUG: KASAN: use-after-free in j1939_sock_pending_del+0x20/0x70 net/can/j1939/socket.c:73
Write of size 4 at addr ffff888097bd84c0 by task syz-executor.1/16704

CPU: 0 PID: 16704 Comm: syz-executor.1 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 print_address_description+0x75/0x5c0 mm/kasan/report.c:374
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
 kasan_report+0x26/0x50 mm/kasan/common.c:634
 check_memory_region_inline mm/kasan/generic.c:182 [inline]
 check_memory_region+0x2cf/0x2e0 mm/kasan/generic.c:192
 __kasan_check_write+0x14/0x20 mm/kasan/common.c:98
 atomic_sub_return include/asm-generic/atomic-instrumented.h:159 [inline]
 atomic_dec_return include/linux/atomic-fallback.h:455 [inline]
 j1939_sock_pending_del+0x20/0x70 net/can/j1939/socket.c:73
 __j1939_session_drop net/can/j1939/transport.c:257 [inline]
 j1939_session_destroy net/can/j1939/transport.c:270 [inline]
 __j1939_session_release net/can/j1939/transport.c:280 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0xd2/0x150 net/can/j1939/transport.c:285
 j1939_tp_rxtimer+0x2d1/0xb80 net/can/j1939/transport.c:1177
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
 hrtimer_run_softirq+0x18f/0x1f0 kernel/time/hrtimer.c:1593
 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:766
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x227/0x230 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x113/0x280 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x5f/0x80 kernel/locking/spinlock.c:199
Code: 00 00 00 00 fc ff df 80 3c 08 00 74 0c 48 c7 c7 00 92 8a 88 e8 52 99 31 fa 48 83 3d 6a 96 0f 01 00 74 26 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 d7 13 d5 f9 65 8b 05 1c 02 87 78 85 c0 74 03 5b
RSP: 0018:ffff888051be7a80 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff1115240 RBX: ffff8880aea34980 RCX: dffffc0000000000
RDX: 0000000040000002 RSI: ffffffff81513b21 RDI: ffff888050a66b84
RBP: ffff888051be7a88 R08: ffff888050a66b98 R09: ffffed1015d46931
R10: ffffed1015d46931 R11: 0000000000000000 R12: ffff8880aea34980
R13: ffff888050a66340 R14: ffff8880aea35380 R15: dffffc0000000000
 finish_lock_switch+0x31/0x40 kernel/sched/core.c:3123
 finish_task_switch+0x24f/0x550 kernel/sched/core.c:3223
 context_switch kernel/sched/core.c:3387 [inline]
 __schedule+0x7bf/0xc30 kernel/sched/core.c:4078
 schedule+0x131/0x1e0 kernel/sched/core.c:4145
 pipe_wait+0x127/0x1e0 fs/pipe.c:117
 pipe_write+0x7d2/0xeb0 fs/pipe.c:497
 call_write_iter include/linux/fs.h:1895 [inline]
 new_sync_write fs/read_write.c:483 [inline]
 __vfs_write+0x5a1/0x740 fs/read_write.c:496
 vfs_write+0x275/0x590 fs/read_write.c:558
 ksys_write+0x117/0x220 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:620
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a219
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6b702adc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a219
RDX: 0000000041395527 RSI: 0000000020000340 RDI: 0000000000000006
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6b702ae6d4
R13: 00000000004c6cf5 R14: 00000000004e2238 R15: 00000000ffffffff

Allocated by task 16679:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:510
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x254/0x340 mm/slab.c:3664
 kmalloc include/linux/slab.h:561 [inline]
 sk_prot_alloc+0xb0/0x290 net/core/sock.c:1605
 sk_alloc+0x38/0x950 net/core/sock.c:1659
 can_create+0x1de/0x480 net/can/af_can.c:157
 __sock_create+0x5cc/0x910 net/socket.c:1418
 sock_create net/socket.c:1469 [inline]
 __sys_socket+0xe7/0x2e0 net/socket.c:1511
 __do_sys_socket net/socket.c:1520 [inline]
 __se_sys_socket net/socket.c:1518 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1518
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16704:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:471
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x115/0x200 mm/slab.c:3756
 sk_prot_free net/core/sock.c:1642 [inline]
 __sk_destruct+0x523/0x620 net/core/sock.c:1726
 sk_destruct net/core/sock.c:1741 [inline]
 __sk_free+0x35d/0x430 net/core/sock.c:1752
 sock_wfree+0x106/0x140 net/core/sock.c:1968
 skb_release_head_state+0x100/0x210 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 net/core/skbuff.c:697 [inline]
 skb_queue_purge+0x1a6/0x260 net/core/skbuff.c:3078
 j1939_session_destroy net/can/j1939/transport.c:269 [inline]
 __j1939_session_release net/can/j1939/transport.c:280 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0x7f/0x150 net/can/j1939/transport.c:285
 j1939_tp_rxtimer+0x2d1/0xb80 net/can/j1939/transport.c:1177
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
 hrtimer_run_softirq+0x18f/0x1f0 kernel/time/hrtimer.c:1593
 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:766

The buggy address belongs to the object at ffff888097bd8000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1216 bytes inside of
 2048-byte region [ffff888097bd8000, ffff888097bd8800)
The buggy address belongs to the page:
page:ffffea00025ef600 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00025cd048 ffffea00025bc748 ffff8880aa400e00
raw: 0000000000000000 ffff888097bd8000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888097bd8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888097bd8400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888097bd8480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888097bd8500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888097bd8580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================