KCSAN: data-race in vxcan_xmit / vxcan_xmit (2)

Status: auto-obsoleted due to no activity on 2026/09/12 03:07
Subsystems: can
Labels: race:benign prio:low
[Documentation on labels]
Reported-by: syzbot+3b27f79825eb8b10ff91@syzkaller.appspotmail.com
First crash: 66d, last: 66d
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
48916063 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KCSAN: data-race in vxcan_xmit / vxcan_xmit (2) 2026/07/20 00:23 2026/07/20 00:23 2026/07/20 01:05 72524a66
895df2a4 assessment-kcsan Benign: ✅ ❓ KCSAN: data-race in vxcan_xmit / vxcan_xmit (2) 2026/07/18 03:06 2026/07/18 03:06 2026/07/18 03:36 8aaff637
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in vxcan_xmit / vxcan_xmit can 6 2 237d 246d 0/29 auto-obsoleted due to no activity on 2026/03/25 20:52

Sample crash report:
==================================================================
BUG: KCSAN: data-race in vxcan_xmit / vxcan_xmit

read-write to 0xffff88811a6e8230 of 8 bytes by interrupt on cpu 0:
 vxcan_xmit+0x2ba/0x370 drivers/net/can/vxcan.c:87
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x18b/0x630 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811a6e8230 of 8 bytes by interrupt on cpu 1:
 vxcan_xmit+0x2ba/0x370 drivers/net/can/vxcan.c:87
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:1076
 smpboot_thread_fn+0x32a/0x510 kernel/smpboot.c:160
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000009bc0 -> 0x0000000000009bc1

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22 Comm: ksoftirqd/1 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
==================================================================
==================================================================
BUG: KCSAN: data-race in can_can_gw_rcv / can_can_gw_rcv

read-write to 0xffff88811ca1af80 of 4 bytes by interrupt on cpu 0:
 can_can_gw_rcv+0x812/0x820 net/can/gw.c:572
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x18b/0x630 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811ca1af80 of 4 bytes by interrupt on cpu 1:
 can_can_gw_rcv+0x812/0x820 net/can/gw.c:572
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 netlink_alloc_large_skb+0xbf/0xf0 net/netlink/af_netlink.c:1185
 netlink_sendmsg+0x40c/0x6f0 net/netlink/af_netlink.c:1875
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x411/0x470 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2255
 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00009c48 -> 0x00009c49

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 14276 Comm: syz.5.2986 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
==================================================================
==================================================================
BUG: KCSAN: data-race in vxcan_xmit / vxcan_xmit

read-write to 0xffff88811a6a8238 of 8 bytes by interrupt on cpu 0:
 vxcan_xmit+0x311/0x370 drivers/net/can/vxcan.c:91
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 update_defense_level+0x594/0x5c0 net/netfilter/ipvs/ip_vs_ctl.c:210
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811a6a8238 of 8 bytes by interrupt on cpu 1:
 vxcan_xmit+0x311/0x370 drivers/net/can/vxcan.c:91
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 update_defense_level+0x594/0x5c0 net/netfilter/ipvs/ip_vs_ctl.c:210
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000064f50 -> 0x0000000000064f58

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3390 Comm: kworker/1:4 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: events_long defense_work_handler
==================================================================
==================================================================
BUG: KCSAN: data-race in can_can_gw_rcv / can_can_gw_rcv

read-write to 0xffff88811ca1af80 of 4 bytes by interrupt on cpu 0:
 can_can_gw_rcv+0x812/0x820 net/can/gw.c:572
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x18b/0x630 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811ca1af80 of 4 bytes by interrupt on cpu 1:
 can_can_gw_rcv+0x812/0x820 net/can/gw.c:572
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:196 [inline]
 _raw_spin_unlock_bh+0x18/0x20 kernel/locking/spinlock.c:214
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_tt_local_purge+0x1a7/0x1f0 net/batman-adv/translation-table.c:1366
 batadv_tt_purge+0x2b/0x610 net/batman-adv/translation-table.c:3565
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00029ce7 -> 0x00029ce8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7851 Comm: kworker/u8:23 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: bat_events batadv_tt_purge
==================================================================
==================================================================
BUG: KCSAN: data-race in vxcan_xmit / vxcan_xmit

read-write to 0xffff88811a6a8228 of 8 bytes by interrupt on cpu 0:
 vxcan_xmit+0x2f7/0x370 drivers/net/can/vxcan.c:90
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x18b/0x630 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811a6a8228 of 8 bytes by interrupt on cpu 1:
 vxcan_xmit+0x2f7/0x370 drivers/net/can/vxcan.c:90
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:196 [inline]
 _raw_spin_unlock_bh+0x18/0x20 kernel/locking/spinlock.c:214
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_tt_local_purge+0x1a7/0x1f0 net/batman-adv/translation-table.c:1366
 batadv_tt_purge+0x2b/0x610 net/batman-adv/translation-table.c:3565
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000000378a6 -> 0x00000000000378a7

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7851 Comm: kworker/u8:23 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: bat_events batadv_tt_purge
==================================================================
==================================================================
BUG: KCSAN: data-race in vxcan_xmit / vxcan_xmit

read-write to 0xffff88811a6a8238 of 8 bytes by interrupt on cpu 0:
 vxcan_xmit+0x311/0x370 drivers/net/can/vxcan.c:91
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:1076
 smpboot_thread_fn+0x32a/0x510 kernel/smpboot.c:160
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811a6a8238 of 8 bytes by interrupt on cpu 1:
 vxcan_xmit+0x311/0x370 drivers/net/can/vxcan.c:91
 __netdev_start_xmit include/linux/netdevice.h:5400 [inline]
 netdev_start_xmit include/linux/netdevice.h:5409 [inline]
 xmit_one net/core/dev.c:3889 [inline]
 dev_hard_start_xmit+0x10c/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xb97/0x1e60 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 can_send+0x584/0x720 net/can/af_can.c:279
 can_can_gw_rcv+0x7c6/0x820 net/can/gw.c:569
 deliver net/can/af_can.c:575 [inline]
 can_rcv_filter+0xc3/0x480 net/can/af_can.c:602
 can_receive+0x13e/0x190 net/can/af_can.c:674
 can_rcv+0x17d/0x1f0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:6206 [inline]
 __netif_receive_skb net/core/dev.c:6319 [inline]
 process_backlog+0x354/0x680 net/core/dev.c:6670
 __napi_poll+0x61/0x300 net/core/dev.c:7729
 napi_poll net/core/dev.c:7792 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7949
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 do_softirq+0x45/0x60 kernel/softirq.c:523
 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 __alloc_skb+0x6b1/0x6f0 net/core/skbuff.c:699
 alloc_skb include/linux/skbuff.h:1384 [inline]
 alloc_skb_with_frags+0x7e/0x3d0 net/core/skbuff.c:6769
 sock_alloc_send_pskb+0x44d/0x500 net/core/sock.c:3010
 unix_dgram_sendmsg+0x384/0x1030 net/unix/af_unix.c:2136
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x411/0x470 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2255
 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000001c4b90 -> 0x00000000001c4b98

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2969 Comm: klogd Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/18 03:06 upstream 111e7b23e5b0 8aaff637 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in vxcan_xmit / vxcan_xmit
* Struck through repros no longer work on HEAD.