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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff888109914310 of 184 bytes by task 13135 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+0x10c/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:6675
 skb_kfree_head net/core/skbuff.c:1046 [inline]
 skb_free_head+0x87/0x150 net/core/skbuff.c:1060
 skb_release_data+0x33b/0x370 net/core/skbuff.c:1087
 skb_release_all net/core/skbuff.c:1152 [inline]
 __kfree_skb+0x44/0x150 net/core/skbuff.c:1166
 sk_skb_reason_drop+0xbd/0x270 net/core/skbuff.c:1204
 kfree_skb_reason include/linux/skbuff.h:1322 [inline]
 kfree_skb include/linux/skbuff.h:1331 [inline]
 tipc_group_filter_msg+0x2d2/0xb30 net/tipc/group.c:585
 tipc_sk_filter_rcv+0x1912/0x1a00 net/tipc/socket.c:2353
 tipc_sk_backlog_rcv+0x68/0xc0 net/tipc/socket.c:2405
 sk_backlog_rcv+0x87/0x190 include/net/sock.h:1158
 __release_sock+0xc5/0x160 net/core/sock.c:3180
 release_sock+0x44/0x150 net/core/sock.c:3735
 tipc_sendmsg+0x48/0x60 net/tipc/socket.c:1400
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:742
 ____sys_sendmsg+0x345/0x4e0 net/socket.c:2630
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684
 __sys_sendmmsg+0x178/0x300 net/socket.c:2773
 __do_sys_sendmmsg net/socket.c:2800 [inline]
 __se_sys_sendmmsg net/socket.c:2797 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2797
 x64_sys_call+0x1c4a/0x3000 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 0xffff888109914348 of 8 bytes by task 5587 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+0x10c/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:6675
 __io_req_caches_free+0xfe/0x210 io_uring/io_uring.c:2824
 io_req_caches_free+0x1f/0x60 io_uring/io_uring.c:2836
 io_ring_exit_work+0x26d/0x560 io_uring/io_uring.c:3034
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x486/0x510 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

value changed: 0xffffffff813cf02b -> 0xffffffff844f5d9d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5587 Comm: kworker/u8:34 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: iou_exit io_ring_exit_work
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