==================================================================
BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff88810c97c0f8 of 184 bytes by task 9112 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_run3+0x10f/0x1d0 kernel/trace/bpf_trace.c:2117
 __do_trace_kmem_cache_free include/trace/events/kmem.h:117 [inline]
 trace_kmem_cache_free include/trace/events/kmem.h:117 [inline]
 kmem_cache_free+0x329/0x3d0 mm/slub.c:6683
 kfree_skbmem net/core/skbuff.c:-1 [inline]
 __kfree_skb+0x109/0x150 net/core/skbuff.c:1167
 consume_skb+0x49/0x150 net/core/skbuff.c:1398
 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1495 [inline]
 sctp_chunk_put+0xd4/0x140 net/sctp/sm_make_chunk.c:1522
 sctp_chunk_free+0x43/0x50 net/sctp/sm_make_chunk.c:1509
 sctp_packet_pack net/sctp/output.c:513 [inline]
 sctp_packet_transmit+0xbb3/0x1510 net/sctp/output.c:621
 sctp_outq_flush_transports net/sctp/outqueue.c:1173 [inline]
 sctp_outq_flush+0x807/0x1970 net/sctp/outqueue.c:1221
 sctp_outq_uncork+0x56/0x70 net/sctp/outqueue.c:764
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1332 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1204 [inline]
 sctp_do_sm+0x1228/0x3230 net/sctp/sm_sideeffect.c:1175
 sctp_primitive_ABORT+0x74/0x90 net/sctp/primitive.c:104
 sctp_close+0x1aa/0x550 net/sctp/socket.c:1526
 inet_release+0xce/0xf0 net/ipv4/af_inet.c:437
 inet6_release+0x3e/0x60 net/ipv6/af_inet6.c:487
 __sock_release net/socket.c:662 [inline]
 sock_close+0x6b/0x150 net/socket.c:1455
 __fput+0x29b/0x650 fs/file_table.c:468
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xed/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810c97c120 of 8 bytes by task 4103 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_run3+0x10f/0x1d0 kernel/trace/bpf_trace.c:2117
 __do_trace_kmem_cache_free include/trace/events/kmem.h:117 [inline]
 trace_kmem_cache_free include/trace/events/kmem.h:117 [inline]
 kmem_cache_free+0x329/0x3d0 mm/slub.c:6683
 putname+0xda/0x100 fs/namei.c:297
 do_sys_openat2+0xd9/0x110 fs/open.c:1445
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1463
 x64_sys_call+0x2eab/0x3000 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0xffffffff8190f0b9 -> 0xffffffff844f60b9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4103 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================