syz.7.6939[30100] is installing a program with bpf_probe_write_user helper that may corrupt user memory!
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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff86727870 of 8 bytes by task 30020 on cpu 0:
 prb_reserve+0x740/0xb60
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2301
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68
 _printk+0x7a/0xa0 kernel/printk/printk.c:2432
 br_set_state+0x290/0x390 net/bridge/br_stp.c:57
 new_nbp+0x240/0x310 net/bridge/br_if.c:443
 br_add_if+0x1ef/0xa50 net/bridge/br_if.c:599
 br_add_slave+0x2c/0x40 net/bridge/br_device.c:373
 do_set_master net/core/rtnetlink.c:2730 [inline]
 do_setlink+0x96b/0x2490 net/core/rtnetlink.c:2936
 __rtnl_newlink net/core/rtnetlink.c:3725 [inline]
 rtnl_newlink+0x11a3/0x1690 net/core/rtnetlink.c:3772
 rtnetlink_rcv_msg+0x6aa/0x710 net/core/rtnetlink.c:6675
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2551
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:744
 __sys_sendto+0x1d6/0x260 net/socket.c:2214
 __do_sys_sendto net/socket.c:2226 [inline]
 __se_sys_sendto net/socket.c:2222 [inline]
 __x64_sys_sendto+0x78/0x90 net/socket.c:2222
 x64_sys_call+0x2959/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86727870 of 8 bytes by task 30100 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline]
 _prb_read_valid+0x3bb/0xba0 kernel/printk/printk_ringbuffer.c:2114
 prb_read_valid+0x3d/0x60 kernel/printk/printk_ringbuffer.c:2182
 printk_get_next_message+0xd8/0x6f0 kernel/printk/printk.c:2963
 console_emit_next_record kernel/printk/printk.c:3046 [inline]
 console_flush_all+0x28a/0x770 kernel/printk/printk.c:3180
 __console_flush_and_unlock kernel/printk/printk.c:3239 [inline]
 console_unlock+0xab/0x330 kernel/printk/printk.c:3279
 vprintk_emit+0x3f4/0x680 kernel/printk/printk.c:2407
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68
 _printk+0x7a/0xa0 kernel/printk/printk.c:2432
 bpf_get_probe_write_proto+0x8b/0x90 kernel/trace/bpf_trace.c:365
 bpf_tracing_func_proto+0x596/0x790 kernel/trace/bpf_trace.c:1466
 raw_tp_prog_func_proto+0x65/0xc0 kernel/trace/bpf_trace.c:1938
 get_helper_proto kernel/bpf/verifier.c:10421 [inline]
 mark_fastcall_pattern_for_call kernel/bpf/verifier.c:16272 [inline]
 mark_fastcall_patterns+0x563/0xd30 kernel/bpf/verifier.c:16383
 bpf_check+0xa7c4/0xcbf0 kernel/bpf/verifier.c:22414
 bpf_prog_load+0xed4/0x1070 kernel/bpf/syscall.c:2846
 __sys_bpf+0x463/0x7a0 kernel/bpf/syscall.c:5653
 __do_sys_bpf kernel/bpf/syscall.c:5760 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5758 [inline]
 __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5758
 x64_sys_call+0x2625/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000001ace -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 30100 Comm: syz.7.6939 Not tainted 6.12.0-rc6-syzkaller-00110-gff7afaeca1a1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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