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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff888150a94310 of 96 bytes by task 3419 on cpu 0:
 __bpf_get_stackid+0x761/0x800 kernel/bpf/stackmap.c:288
 ____bpf_get_stackid kernel/bpf/stackmap.c:324 [inline]
 bpf_get_stackid+0xe9/0x120 kernel/bpf/stackmap.c:300
 ____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:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x104/0x1c0 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+0x351/0x400 mm/slub.c:6760
 __bpf_prog_free+0x53/0xa0 kernel/bpf/core.c:290
 bpf_prog_unlock_free include/linux/filter.h:1107 [inline]
 bpf_jit_free+0x273/0x2f0 arch/x86/net/bpf_jit_comp.c:3919
 bpf_prog_free_deferred+0x41d/0x470 kernel/bpf/core.c:2898
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888150a94340 of 8 bytes by task 10237 on cpu 1:
 memcmp lib/string.c:683 [inline]
 bcmp+0x23/0x90 lib/string.c:715
 memcmp include/linux/fortify-string.h:727 [inline]
 __bpf_get_stackid+0x371/0x800 kernel/bpf/stackmap.c:279
 ____bpf_get_stackid kernel/bpf/stackmap.c:324 [inline]
 bpf_get_stackid+0xe9/0x120 kernel/bpf/stackmap.c:300
 ____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:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x104/0x1c0 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+0x351/0x400 mm/slub.c:6760
 kernfs_file_read_iter fs/kernfs/file.c:290 [inline]
 kernfs_fop_read_iter+0x2cc/0x330 fs/kernfs/file.c:298
 io_iter_do_read io_uring/rw.c:830 [inline]
 __io_read+0x43f/0xc30 io_uring/rw.c:947
 io_read+0x4a/0x180 io_uring/rw.c:1027
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1824
 io_issue_sqe+0x56/0xa80 io_uring/io_uring.c:1847
 io_queue_sqe io_uring/io_uring.c:2074 [inline]
 io_submit_sqe io_uring/io_uring.c:2334 [inline]
 io_submit_sqes+0x675/0x1060 io_uring/io_uring.c:2447
 __do_sys_io_uring_enter io_uring/io_uring.c:3514 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3453
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3453
 x64_sys_call+0x2df0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffff81e7c46a -> 0xffffffff8160665d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 10237 Comm: syz.0.2505 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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