IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready hrtimer: interrupt took 41328 ns ================================================================== BUG: KASAN: use-after-free in bcm_can_tx+0x726/0x800 net/can/bcm.c:295 Read of size 4 at addr ffff88809495cf04 by task kworker/u4:5/3570 CPU: 0 PID: 3570 Comm: kworker/u4:5 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: bat_events batadv_nc_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432 bcm_can_tx+0x726/0x800 net/can/bcm.c:295 bcm_tx_timeout_tsklet+0x1f0/0x3a0 net/can/bcm.c:414 tasklet_action_common.constprop.0+0x265/0x360 kernel/softirq.c:522 __do_softirq+0x265/0x980 kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1092 do_softirq.part.0+0x160/0x1c0 kernel/softirq.c:336 do_softirq kernel/softirq.c:328 [inline] __local_bh_enable_ip+0x20e/0x270 kernel/softirq.c:189 spin_unlock_bh include/linux/spinlock.h:374 [inline] batadv_nc_purge_paths+0x22d/0x310 net/batman-adv/network-coding.c:482 batadv_nc_worker+0x6fa/0xd50 net/batman-adv/network-coding.c:731 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 8339: kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] bcm_tx_setup net/can/bcm.c:947 [inline] bcm_sendmsg+0x25d7/0x4150 net/can/bcm.c:1386 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:661 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227 __sys_sendmsg net/socket.c:2265 [inline] __do_sys_sendmsg net/socket.c:2274 [inline] __se_sys_sendmsg net/socket.c:2272 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8339: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 bcm_release+0x260/0x950 net/can/bcm.c:1561 __sock_release+0xcd/0x2a0 net/socket.c:599 sock_close+0x15/0x20 net/socket.c:1214 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809495cdc0 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 324 bytes inside of 1024-byte region [ffff88809495cdc0, ffff88809495d1c0) The buggy address belongs to the page: page:ffffea0002525700 count:1 mapcount:0 mapping:ffff88813bff0ac0 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea00024fec08 ffff88813bff1848 ffff88813bff0ac0 raw: 0000000000000000 ffff88809495c040 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809495ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809495ce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809495cf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809495cf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809495d000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================