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BUG: KASAN: use-after-free in memcpy include/linux/string.h:406 [inline]
BUG: KASAN: use-after-free in j1939_session_tx_dat net/can/j1939/transport.c:790 [inline]
BUG: KASAN: use-after-free in j1939_xtp_txnext_transmiter net/can/j1939/transport.c:847 [inline]
BUG: KASAN: use-after-free in j1939_tp_txtimer+0x787/0x1e10 net/can/j1939/transport.c:1095
Read of size 7 at addr ffff88804617fe72 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.8.0-rc4-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 memcpy+0x20/0x60 mm/kasan/common.c:105
 memcpy include/linux/string.h:406 [inline]
 j1939_session_tx_dat net/can/j1939/transport.c:790 [inline]
 j1939_xtp_txnext_transmiter net/can/j1939/transport.c:847 [inline]
 j1939_tp_txtimer+0x787/0x1e10 net/can/j1939/transport.c:1095
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x6a9/0xfc0 kernel/time/hrtimer.c:1584
 hrtimer_run_softirq+0x172/0x340 kernel/time/hrtimer.c:1601
 __do_softirq+0x34c/0xa60 kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:630 [inline]
 run_ksoftirqd+0x89/0x100 kernel/softirq.c:622
 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 9:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 slab_post_alloc_hook mm/slab.h:586 [inline]
 slab_alloc_node mm/slab.c:3263 [inline]
 kmem_cache_alloc_node+0x130/0x3c0 mm/slab.c:3575
 __alloc_skb+0x71/0x550 net/core/skbuff.c:198
 alloc_skb include/linux/skbuff.h:1083 [inline]
 j1939_tp_tx_dat_new+0x30/0x500 net/can/j1939/transport.c:568
 j1939_tp_tx_dat net/can/j1939/transport.c:606 [inline]
 j1939_session_tx_dat net/can/j1939/transport.c:791 [inline]
 j1939_xtp_txnext_transmiter net/can/j1939/transport.c:847 [inline]
 j1939_tp_txtimer+0x7b3/0x1e10 net/can/j1939/transport.c:1095
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x6a9/0xfc0 kernel/time/hrtimer.c:1584
 hrtimer_run_softirq+0x172/0x340 kernel/time/hrtimer.c:1601
 __do_softirq+0x34c/0xa60 kernel/softirq.c:292

Freed by task 9:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7f/0x310 mm/slab.c:3694
 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:622
 __kfree_skb net/core/skbuff.c:679 [inline]
 consume_skb net/core/skbuff.c:837 [inline]
 consume_skb+0xcf/0x160 net/core/skbuff.c:831
 vcan_tx+0x4f0/0xaa0 drivers/net/can/vcan.c:110
 __netdev_start_xmit include/linux/netdevice.h:4611 [inline]
 netdev_start_xmit include/linux/netdevice.h:4625 [inline]
 xmit_one net/core/dev.c:3556 [inline]
 dev_hard_start_xmit+0x193/0x950 net/core/dev.c:3572
 __dev_queue_xmit+0x2091/0x2d60 net/core/dev.c:4131
 can_send+0x41c/0x860 net/can/af_can.c:277
 j1939_send_one+0x288/0x340 net/can/j1939/main.c:340
 j1939_tp_tx_dat net/can/j1939/transport.c:615 [inline]
 j1939_session_tx_dat net/can/j1939/transport.c:791 [inline]
 j1939_xtp_txnext_transmiter net/can/j1939/transport.c:847 [inline]
 j1939_tp_txtimer+0x5d6/0x1e10 net/can/j1939/transport.c:1095
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x6a9/0xfc0 kernel/time/hrtimer.c:1584
 hrtimer_run_softirq+0x172/0x340 kernel/time/hrtimer.c:1601
 __do_softirq+0x34c/0xa60 kernel/softirq.c:292

The buggy address belongs to the object at ffff88804617fe40
 which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 50 bytes inside of
 224-byte region [ffff88804617fe40, ffff88804617ff20)
The buggy address belongs to the page:
page:ffffea0001185fc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88804617fe40
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002429cc8 ffffea00022e1cc8 ffff88821b77e8c0
raw: ffff88804617fe40 ffff88804617f080 0000000100000009 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804617fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804617fd80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88804617fe00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                             ^
 ffff88804617fe80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804617ff00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
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