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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff8881293f8870 of 96 bytes by task 19501 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+0x104/0x1c0 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
 __bpf_prog_put_noref+0xd0/0x230 kernel/bpf/syscall.c:2335
 bpf_prog_load+0xfc9/0x1070 kernel/bpf/syscall.c:3012
 __sys_bpf+0x51d/0x790 kernel/bpf/syscall.c:5836
 __do_sys_bpf kernel/bpf/syscall.c:5943 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5941 [inline]
 __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:5941
 x64_sys_call+0x2478/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:322
 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 0xffff8881293f8898 of 8 bytes by task 19505 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+0x104/0x1c0 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
 context_destroy security/selinux/ss/context.h:185 [inline]
 security_compute_sid+0x11da/0x1290 security/selinux/ss/services.c:1926
 security_transition_sid+0x5a/0x70 security/selinux/ss/services.c:1948
 selinux_determine_inode_label+0x1e3/0x210 security/selinux/hooks.c:1803
 may_create+0x1e2/0x2b0 security/selinux/hooks.c:1837
 selinux_inode_symlink+0x22/0x30 security/selinux/hooks.c:3041
 security_inode_symlink+0x79/0xc0 security/security.c:2180
 vfs_symlink+0x84/0x1e0 fs/namei.c:4735
 do_symlinkat+0xc7/0x3c0 fs/namei.c:4765
 __do_sys_symlinkat fs/namei.c:4781 [inline]
 __se_sys_symlinkat fs/namei.c:4778 [inline]
 __x64_sys_symlinkat+0x5a/0x70 fs/namei.c:4778
 x64_sys_call+0x1558/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:267
 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: 0xffffffff81d5a54a -> 0xffffffff8161de00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 19505 Comm: syz-executor Not tainted 6.16.0-rc5-syzkaller-00224-g379f604cc3dc #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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