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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff88811ccfa190 of 216 bytes by interrupt on cpu 1:
 __bpf_get_stackid+0x761/0x800 kernel/bpf/stackmap.c:288
 ____bpf_get_stackid kernel/bpf/stackmap.c:324 [inline]
 bpf_get_stackid+0xee/0x120 kernel/bpf/stackmap.c:300
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1811 [inline]
 bpf_get_stackid_raw_tp+0xf6/0x120 kernel/trace/bpf_trace.c:1800
 bpf_prog_e6fc920cfeff8120+0x2a/0x32
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
 __bpf_prog_run include/linux/filter.h:718 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline]
 bpf_trace_run2+0x107/0x1c0 kernel/trace/bpf_trace.c:2299
 __traceiter_kfree+0x2e/0x50 include/trace/events/kmem.h:94
 __do_trace_kfree include/trace/events/kmem.h:94 [inline]
 trace_kfree include/trace/events/kmem.h:94 [inline]
 kfree+0x27b/0x320 mm/slub.c:4829
 shmem_free_in_core_inode+0x50/0x80 mm/shmem.c:5159
 i_callback+0x36/0x70 fs/inode.c:325
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 rcu_core+0x5a2/0xc00 kernel/rcu/tree.c:2832
 rcu_core_si+0xd/0x20 kernel/rcu/tree.c:2849
 handle_softirqs+0xb7/0x290 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x3a/0xc0 kernel/softirq.c:680
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x74/0x80 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 finish_task_switch+0xb6/0x2b0 kernel/sched/core.c:5265
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x6a8/0xb30 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6864 [inline]
 schedule+0x5f/0xd0 kernel/sched/core.c:6879
 schedule_timeout+0x53/0x170 kernel/time/sleep_timeout.c:75
 unix_wait_for_peer+0x113/0x170 net/unix/af_unix.c:1591
 unix_dgram_sendmsg+0x8aa/0xfc0 net/unix/af_unix.c:2222
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x142/0x180 net/socket.c:727
 ____sys_sendmsg+0x345/0x4e0 net/socket.c:2612
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2666
 __sys_sendmmsg+0x178/0x300 net/socket.c:2755
 __do_sys_sendmmsg net/socket.c:2782 [inline]
 __se_sys_sendmmsg net/socket.c:2779 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2779
 x64_sys_call+0x1c4a/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:308
 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

read to 0xffff88811ccfa1e0 of 8 bytes by task 12981 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+0x371/0x800 kernel/bpf/stackmap.c:279
 ____bpf_get_stackid kernel/bpf/stackmap.c:324 [inline]
 bpf_get_stackid+0xee/0x120 kernel/bpf/stackmap.c:300
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1811 [inline]
 bpf_get_stackid_raw_tp+0xf6/0x120 kernel/trace/bpf_trace.c:1800
 bpf_prog_e6fc920cfeff8120+0x2a/0x32
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
 __bpf_prog_run include/linux/filter.h:718 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline]
 bpf_trace_run2+0x107/0x1c0 kernel/trace/bpf_trace.c:2299
 __traceiter_kfree+0x2e/0x50 include/trace/events/kmem.h:94
 __do_trace_kfree include/trace/events/kmem.h:94 [inline]
 trace_kfree include/trace/events/kmem.h:94 [inline]
 kfree+0x27b/0x320 mm/slub.c:4829
 ___sys_recvmsg+0x135/0x370 net/socket.c:2875
 do_recvmmsg+0x1ef/0x540 net/socket.c:2969
 __sys_recvmmsg net/socket.c:3043 [inline]
 __do_sys_recvmmsg net/socket.c:3066 [inline]
 __se_sys_recvmmsg net/socket.c:3059 [inline]
 __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3059
 x64_sys_call+0x27a6/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:300
 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: 0xffffffff81000130 -> 0xffffffff8139e42a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 12981 Comm: syz.6.3210 Not tainted 6.16.0-syzkaller-03556-g0919a5b3b11c #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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