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BUG: KCSAN: data-race in __bpf_get_stackid / bcmp

write to 0xffff88814083c310 of 136 bytes by task 8514 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+0xee/0x120 kernel/bpf/stackmap.c:300
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1810 [inline]
 bpf_get_stackid_raw_tp+0xf6/0x120 kernel/trace/bpf_trace.c:1799
 bpf_prog_e6fc920cfeff8120+0x2a/0x32
 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [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:2257 [inline]
 bpf_trace_run4+0x117/0x1d0 kernel/trace/bpf_trace.c:2300
 __do_trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
 trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
 __alloc_frozen_pages_noprof+0x32d/0x360 mm/page_alloc.c:5170
 __alloc_pages_noprof mm/page_alloc.c:5182 [inline]
 alloc_pages_bulk_noprof+0x4b8/0x540 mm/page_alloc.c:5102
 alloc_pages_bulk_weighted_interleave mm/mempolicy.c:2595 [inline]
 alloc_pages_bulk_mempolicy_noprof+0x397/0xb00 mm/mempolicy.c:2715
 vm_area_alloc_pages mm/vmalloc.c:3616 [inline]
 __vmalloc_area_node mm/vmalloc.c:3720 [inline]
 __vmalloc_node_range_noprof+0x52b/0xe00 mm/vmalloc.c:3893
 __vmalloc_node_noprof mm/vmalloc.c:3956 [inline]
 vmalloc_noprof+0x82/0xc0 mm/vmalloc.c:3989
 bpf_prog_calc_tag+0x71/0x3c0 kernel/bpf/core.c:307
 resolve_pseudo_ldimm64+0x45/0x740 kernel/bpf/verifier.c:20536
 bpf_check+0x1074/0xd9e0 kernel/bpf/verifier.c:24677
 bpf_prog_load+0xedd/0x1070 kernel/bpf/syscall.c:2979
 __sys_bpf+0x462/0x7b0 kernel/bpf/syscall.c:6029
 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6137 [inline]
 __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6137
 x64_sys_call+0x2aea/0x2ff0 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 0xffff88814083c350 of 8 bytes by task 8513 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+0xee/0x120 kernel/bpf/stackmap.c:300
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1810 [inline]
 bpf_get_stackid_raw_tp+0xf6/0x120 kernel/trace/bpf_trace.c:1799
 bpf_prog_e6fc920cfeff8120+0x2a/0x32
 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [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:2257 [inline]
 bpf_trace_run4+0x117/0x1d0 kernel/trace/bpf_trace.c:2300
 __do_trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
 trace_mm_page_alloc include/trace/events/kmem.h:177 [inline]
 __alloc_frozen_pages_noprof+0x32d/0x360 mm/page_alloc.c:5170
 alloc_pages_mpol+0xb3/0x250 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
 vma_alloc_folio_noprof+0x1aa/0x300 mm/mempolicy.c:2470
 folio_prealloc mm/memory.c:-1 [inline]
 wp_page_copy mm/memory.c:3552 [inline]
 do_wp_page+0x5db/0x24e0 mm/memory.c:4013
 handle_pte_fault mm/memory.c:6068 [inline]
 __handle_mm_fault mm/memory.c:6195 [inline]
 handle_mm_fault+0x77d/0x2c20 mm/memory.c:6364
 do_user_addr_fault+0x636/0x1090 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0xffffffff8134fe16 -> 0xffffffff8160bfd1

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 8513 Comm: syz.2.1617 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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