==================================================================
BUG: KASAN: use-after-free in tasklet_action+0x29f/0x340 kernel/softirq.c:506
Read of size 8 at addr ffff8880a7c2ce50 by task syz-executor.5/18274

CPU: 0 PID: 18274 Comm: syz-executor.5 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc 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+0xa9/0x2b9 mm/kasan/report.c:393
 tasklet_action+0x29f/0x340 kernel/softirq.c:506
 __do_softirq+0x254/0x9bf kernel/softirq.c:288
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1016
 </IRQ>
 do_softirq kernel/softirq.c:332 [inline]
 do_softirq+0xdf/0x170 kernel/softirq.c:319
 __local_bh_enable_ip+0x11d/0x160 kernel/softirq.c:185
 sock_orphan include/net/sock.h:1712 [inline]
 bcm_release+0x48b/0x5c0 net/can/bcm.c:1582
 __sock_release+0xcd/0x2b0 net/socket.c:602
 sock_close+0x15/0x20 net/socket.c:1139
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 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+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x416721
RSP: 002b:00007ffe7d262770 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000416721
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000081298de8 R09: 0000000000000000
R10: 00007ffe7d262860 R11: 0000000000000293 R12: 0000000000790ba0
R13: 0000000000108b90 R14: ffffffffffffffff R15: 000000000078bf0c

Allocated by task 18277:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x14d/0x3f0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 bcm_tx_setup net/can/bcm.c:952 [inline]
 bcm_sendmsg+0x219c/0x3770 net/can/bcm.c:1388
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 18274:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 bcm_release+0xff/0x5c0 net/can/bcm.c:1540
 __sock_release+0xcd/0x2b0 net/socket.c:602
 sock_close+0x15/0x20 net/socket.c:1139
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 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+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880a7c2cd80
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 208 bytes inside of
 1024-byte region [ffff8880a7c2cd80, ffff8880a7c2d180)
The buggy address belongs to the page:
page:ffffea00029f0b00 count:1 mapcount:0 mapping:ffff8880a7c2c000 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a7c2c000 0000000000000000 0000000100000007
raw: ffffea000231fea0 ffff8880aa801848 ffff8880aa800ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a7c2cd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a7c2cd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a7c2ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8880a7c2ce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a7c2cf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================