syzbot

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BUG: KCSAN: data-race in __bpf_get_stackid / __bpf_get_stackid

write to 0xffff8881646d3030 of 4 bytes by task 25391 on cpu 0:
 __bpf_get_stackid+0x740/0x7d0 kernel/bpf/stackmap.c:314
 ____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
 __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
 kobject_uevent_env+0x28d/0x570 lib/kobject_uevent.c:640
 kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:656
 device_add+0x41f/0x770 drivers/base/core.c:3670
 wakeup_source_device_create drivers/base/power/wakeup_stats.c:163 [inline]
 wakeup_source_sysfs_add+0x15a/0x1d0 drivers/base/power/wakeup_stats.c:183
 wakeup_source_register+0xfd/0x240 drivers/base/power/wakeup.c:218
 ep_create_wakeup_source fs/eventpoll.c:1501 [inline]
 ep_insert+0x8bd/0xdb0 fs/eventpoll.c:1630
 do_epoll_ctl+0x686/0x8a0 fs/eventpoll.c:2340
 __do_sys_epoll_ctl fs/eventpoll.c:2391 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2382 [inline]
 __x64_sys_epoll_ctl+0xcb/0x100 fs/eventpoll.c:2382
 x64_sys_call+0x745/0x3000 arch/x86/include/generated/asm/syscalls_64.h:234
 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 0xffff8881646d3030 of 4 bytes by task 31 on cpu 1:
 __bpf_get_stackid+0x2dc/0x7d0 kernel/bpf/stackmap.c:272
 ____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
 __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
 kvfree_rcu_list mm/slab_common.c:1560 [inline]
 kfree_rcu_work+0x167/0x1b0 mm/slab_common.c:1612
 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: 0x243ea77b -> 0x4c32853b

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 31 Comm: kworker/u8:1 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: kvfree_rcu_reclaim kfree_rcu_work
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