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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff88815a4f8870 of 104 bytes by task 14997 on cpu 1:
 __bpf_get_stackid+0x737/0x7d0 kernel/bpf/stackmap.c:311
 ____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
 _destroy_id+0x9ef/0xa60 drivers/infiniband/core/cma.c:2085
 destroy_id_handler_unlock+0x64/0x130 drivers/infiniband/core/cma.c:2112
 rdma_destroy_id+0x21/0x30 drivers/infiniband/core/cma.c:2121
 rds_ib_laddr_check+0x191/0x300 net/rds/ib.c:487
 rds_bind+0x431/0xf10 net/rds/bind.c:248
 __sys_bind_socket net/socket.c:1874 [inline]
 __sys_bind+0x1d1/0x2a0 net/socket.c:1905
 __do_sys_bind net/socket.c:1910 [inline]
 __se_sys_bind net/socket.c:1908 [inline]
 __x64_sys_bind+0x3f/0x50 net/socket.c:1908
 x64_sys_call+0x2ceb/0x3000 arch/x86/include/generated/asm/syscalls_64.h:50
 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 0xffff88815a4f88c0 of 8 bytes by task 14998 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+0x382/0x7d0 kernel/bpf/stackmap.c:302
 ____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
 context_destroy security/selinux/ss/context.h:185 [inline]
 security_compute_sid+0x11da/0x1290 security/selinux/ss/services.c:1946
 security_transition_sid+0x5a/0x70 security/selinux/ss/services.c:1968
 selinux_determine_inode_label+0x1e2/0x210 security/selinux/hooks.c:1809
 may_create+0x1e0/0x2b0 security/selinux/hooks.c:1843
 selinux_inode_symlink+0x22/0x30 security/selinux/hooks.c:3062
 security_inode_symlink+0x79/0xc0 security/security.c:1672
 vfs_symlink+0x8e/0x1f0 fs/namei.c:5515
 do_symlinkat+0xf0/0x470 fs/namei.c:5550
 __do_sys_symlinkat fs/namei.c:5571 [inline]
 __se_sys_symlinkat fs/namei.c:5568 [inline]
 __x64_sys_symlinkat+0x5a/0x70 fs/namei.c:5568
 x64_sys_call+0x2a36/0x3000 arch/x86/include/generated/asm/syscalls_64.h:267
 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

value changed: 0xffffffff81953ab0 -> 0xffffffff8127603b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 14998 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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