syzbot

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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff88810b2b0eb8 of 192 bytes by task 10284 on cpu 1:
 __bpf_get_stackid+0x737/0x7d0 kernel/bpf/stackmap.c:311
 ____bpf_get_stackid kernel/bpf/stackmap.c:344 [inline]
 bpf_get_stackid+0xf3/0x130 kernel/bpf/stackmap.c:323
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1628 [inline]
 bpf_get_stackid_raw_tp+0xf6/0x120 kernel/trace/bpf_trace.c:1617
 bpf_prog_53f0063d4d7f65ce+0x2a/0x32
 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x107/0x1d0 kernel/trace/bpf_trace.c:2116
 __traceiter_kfree+0x2e/0x50 include/trace/events/kmem.h:97
 __do_trace_kfree include/trace/events/kmem.h:97 [inline]
 trace_kfree include/trace/events/kmem.h:97 [inline]
 kfree+0x353/0x3c0 mm/slub.c:6865
 kfree_const+0x3e/0x50 mm/util.c:46
 kobject_set_name_vargs+0xb8/0xe0 lib/kobject.c:293
 kobject_set_name+0x83/0xb0 lib/kobject.c:314
 kset_create lib/kobject.c:968 [inline]
 kset_create_and_add+0x5c/0x1a0 lib/kobject.c:1008
 register_queue_kobjects net/core/net-sysfs.c:2106 [inline]
 netdev_register_kobject+0x128/0x220 net/core/net-sysfs.c:2362
 register_netdevice+0x8cf/0xdd0 net/core/dev.c:11393
 __ip_tunnel_create+0x30c/0x420 net/ipv4/ip_tunnel.c:268
 ip_tunnel_init_net+0x1ff/0x480 net/ipv4/ip_tunnel.c:1147
 vti_init_net+0x39/0xf0 net/ipv4/ip_vti.c:517
 ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
 setup_net+0x95/0x220 net/core/net_namespace.c:446
 copy_net_ns+0x309/0x460 net/core/net_namespace.c:581
 create_new_namespaces+0x20e/0x400 kernel/nsproxy.c:130
 copy_namespaces+0x1ad/0x210 kernel/nsproxy.c:195
 copy_process+0xce4/0x1ef0 kernel/fork.c:2224
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2776
 x64_sys_call+0x12d0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810b2b0ee0 of 8 bytes by task 5615 on cpu 0:
 memcmp lib/string.c:683 [inline]
 bcmp+0x23/0x90 lib/string.c:715
 memcmp include/linux/fortify-string.h:727 [inline]
 __bpf_get_stackid+0x382/0x7d0 kernel/bpf/stackmap.c:302
 ____bpf_get_stackid kernel/bpf/stackmap.c:344 [inline]
 bpf_get_stackid+0xf3/0x130 kernel/bpf/stackmap.c:323
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1628 [inline]
 bpf_get_stackid_raw_tp+0xf6/0x120 kernel/trace/bpf_trace.c:1617
 bpf_prog_53f0063d4d7f65ce+0x2a/0x32
 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x107/0x1d0 kernel/trace/bpf_trace.c:2116
 __traceiter_kfree+0x2e/0x50 include/trace/events/kmem.h:97
 __do_trace_kfree include/trace/events/kmem.h:97 [inline]
 trace_kfree include/trace/events/kmem.h:97 [inline]
 kfree+0x353/0x3c0 mm/slub.c:6865
 skb_kfree_head net/core/skbuff.c:1068 [inline]
 skb_free_head+0xb8/0x150 net/core/skbuff.c:1080
 skb_release_data+0x33b/0x370 net/core/skbuff.c:1107
 skb_release_all net/core/skbuff.c:1182 [inline]
 __kfree_skb+0x44/0x150 net/core/skbuff.c:1196
 consume_skb+0x49/0x150 net/core/skbuff.c:1428
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline]
 nsim_dev_trap_report_work+0x533/0x630 drivers/net/netdevsim/dev.c:921
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0xffffffff8455030b -> 0xffffffff85709048

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5615 Comm: kworker/u8:23 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound nsim_dev_trap_report_work
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