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BUG: KCSAN: data-race in __rb_reserve_next / ring_buffer_iter_peek

write to 0xffff88813195c000 of 8 bytes by task 11294 on cpu 0:
 __rb_reserve_next+0x5f1/0x6c0 kernel/trace/ring_buffer.c:4854
 rb_reserve_next_event kernel/trace/ring_buffer.c:4928 [inline]
 ring_buffer_lock_reserve+0x68c/0x830 kernel/trace/ring_buffer.c:4987
 __trace_buffer_lock_reserve kernel/trace/trace.h:1676 [inline]
 trace_event_buffer_lock_reserve+0x148/0x300 kernel/trace/trace.c:1924
 trace_event_buffer_reserve+0x120/0x180 kernel/trace/trace_events.c:688
 do_trace_event_raw_event_kmem_cache_alloc include/trace/events/kmem.h:12 [inline]
 trace_event_raw_event_kmem_cache_alloc+0xb5/0x190 include/trace/events/kmem.h:12
 __do_trace_kmem_cache_alloc include/trace/events/kmem.h:12 [inline]
 trace_kmem_cache_alloc include/trace/events/kmem.h:12 [inline]
 kmem_cache_alloc_noprof+0x309/0x3c0 mm/slub.c:4933
 skb_clone+0x151/0x1f0 net/core/skbuff.c:2116
 dev_queue_xmit_nit+0x13e/0x510 net/core/dev.c:2575
 xmit_one net/core/dev.c:3885 [inline]
 dev_hard_start_xmit+0xba/0x380 net/core/dev.c:3905
 __dev_queue_xmit+0xbfc/0x1e90 net/core/dev.c:4878
 dev_queue_xmit include/linux/netdevice.h:3448 [inline]
 __bpf_tx_skb net/core/filter.c:2156 [inline]
 __bpf_redirect_common net/core/filter.c:2200 [inline]
 __bpf_redirect+0x83a/0x960 net/core/filter.c:2207
 ____bpf_clone_redirect net/core/filter.c:2497 [inline]
 bpf_clone_redirect+0x206/0x280 net/core/filter.c:2460
 bpf_prog_c23cca63f2a1c73b+0x22/0x2a
 bpf_dispatcher_nop_func include/linux/bpf.h:1454 [inline]
 __bpf_prog_run include/linux/filter.h:724 [inline]
 bpf_prog_run include/linux/filter.h:731 [inline]
 bpf_test_run+0x298/0x620 net/bpf/test_run.c:422
 bpf_prog_test_run_skb+0xe67/0x11b0 net/bpf/test_run.c:1225
 bpf_prog_test_run+0x208/0x340 kernel/bpf/syscall.c:4859
 __sys_bpf+0x8da/0xc30 kernel/bpf/syscall.c:6436
 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6534 [inline]
 __x64_sys_bpf+0x69/0x80 kernel/bpf/syscall.c:6534
 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88813195c000 of 8 bytes by task 4563 on cpu 1:
 ring_buffer_iter_empty kernel/trace/ring_buffer.c:5650 [inline]
 rb_iter_peek kernel/trace/ring_buffer.c:6146 [inline]
 ring_buffer_iter_peek+0x265/0xb10 kernel/trace/ring_buffer.c:6308
 peek_next_entry kernel/trace/trace.c:2349 [inline]
 __find_next_entry+0x1a9/0x420 kernel/trace/trace.c:2398
 trace_find_next_entry_inc kernel/trace/trace.c:2672 [inline]
 s_next+0x10e/0x370 kernel/trace/trace.c:2711
 traverse+0x1c1/0x3b0 fs/seq_file.c:121
 seq_lseek+0xb5/0x170 fs/seq_file.c:324
 tracing_lseek+0x63/0x80 kernel/trace/trace.c:3773
 vfs_llseek fs/read_write.c:391 [inline]
 ksys_lseek fs/read_write.c:404 [inline]
 __do_sys_lseek fs/read_write.c:414 [inline]
 __se_sys_lseek fs/read_write.c:412 [inline]
 __x64_sys_lseek+0xe8/0x160 fs/read_write.c:412
 x64_sys_call+0x27ec/0x3020 arch/x86/include/generated/asm/syscalls_64.h:9
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000119330a3fba -> 0x000001193d6e9386

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4563 Comm: syz.9.8615 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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