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BUG: KASAN: use-after-free in tasklet_action+0x2aa/0x360 kernel/softirq.c:506
Read of size 8 at addr ffff8880a0885750 by task syz-executor.2/8594

CPU: 0 PID: 8594 Comm: syz-executor.2 Not tainted 4.14.205-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+0x14b/0x1f1 lib/dump_stack.c:58
 print_address_description.cold.6+0x9/0x1ca mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.7+0x11a/0x2d4 mm/kasan/report.c:409
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 tasklet_action+0x2aa/0x360 kernel/softirq.c:506
 __do_softirq+0x246/0x9b5 kernel/softirq.c:288
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1016
 </IRQ>
 do_softirq+0xee/0x160 kernel/softirq.c:332
 __local_bh_enable_ip+0x130/0x150 kernel/softirq.c:185
 __raw_write_unlock_bh include/linux/rwlock_api_smp.h:275 [inline]
 _raw_write_unlock_bh+0x30/0x40 kernel/locking/spinlock.c:352
 sock_orphan include/net/sock.h:1715 [inline]
 bcm_release+0x3cf/0x500 net/can/bcm.c:1582
 __sock_release+0xc2/0x2a0 net/socket.c:602
 sock_close+0x10/0x20 net/socket.c:1139
 __fput+0x232/0x740 fs/file_table.c:210
 ____fput+0x9/0x10 fs/file_table.c:244
 task_work_run+0xe5/0x170 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x953/0x2c40 kernel/exit.c:865
 do_group_exit+0xf8/0x2c0 kernel/exit.c:962
 get_signal+0x2f6/0x1ab0 kernel/signal.c:2423
 do_signal+0x7f/0x18b0 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x11e/0x190 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x416/0x5b0 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45de59
RSP: 002b:00007ffeda2815e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 000000000000002d RCX: 000000000045de59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118bf2c
RBP: 000000000118bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffeda2816c0 R11: 0000000000000246 R12: 0000000000057f38
R13: 0000000000057f0b R14: 00000000000003e8 R15: 000000000118bf2c

Allocated by task 8600:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:551
 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:536
 kmem_cache_alloc_trace+0x152/0x3f0 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+0x1994/0x4520 net/can/bcm.c:1388
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xac/0xf0 net/socket.c:656
 ___sys_sendmsg+0x625/0x920 net/socket.c:2062
 __sys_sendmsg+0xc1/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0xd/0x20 net/socket.c:2103
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 8594:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xab/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcc/0x270 mm/slab.c:3815
 bcm_remove_op+0x1cd/0x240 net/can/bcm.c:781
 bcm_release+0xe7/0x500 net/can/bcm.c:1540
 __sock_release+0xc2/0x2a0 net/socket.c:602
 sock_close+0x10/0x20 net/socket.c:1139
 __fput+0x232/0x740 fs/file_table.c:210
 ____fput+0x9/0x10 fs/file_table.c:244
 task_work_run+0xe5/0x170 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x953/0x2c40 kernel/exit.c:865
 do_group_exit+0xf8/0x2c0 kernel/exit.c:962
 get_signal+0x2f6/0x1ab0 kernel/signal.c:2423
 do_signal+0x7f/0x18b0 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x11e/0x190 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x416/0x5b0 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880a0885680
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 208 bytes inside of
 1024-byte region [ffff8880a0885680, ffff8880a0885a80)
The buggy address belongs to the page:
page:ffffea0002822100 count:1 mapcount:0 mapping:ffff8880a0884000 index:0xffff8880a0885b00 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a0884000 ffff8880a0885b00 0000000100000005
raw: ffffea00029100a0 ffffea0002629020 ffff8880b6400ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a0885600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a0885680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a0885700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8880a0885780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0885800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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