BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff88bd8188 of 8 bytes by task 6132 on cpu 1:
 data_alloc+0x216/0x2c0 kernel/printk/printk_ringbuffer.c:1082
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x168/0x690 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 printk_stack_address arch/x86/kernel/dumpstack.c:72 [inline]
 show_trace_log_lvl+0x380/0x400 arch/x86/kernel/dumpstack.c:285
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xf2/0x150 lib/dump_stack.c:120
 dump_stack+0x15/0x1a lib/dump_stack.c:129
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x24a/0x260 lib/fault-inject.c:174
 should_failslab+0x8f/0xb0 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4068 [inline]
 slab_alloc_node mm/slub.c:4144 [inline]
 kmem_cache_alloc_node_noprof+0x59/0x320 mm/slub.c:4216
 __alloc_skb+0x10b/0x310 net/core/skbuff.c:596
 alloc_skb include/linux/skbuff.h:1331 [inline]
 netlink_alloc_large_skb+0xad/0xe0 net/netlink/af_netlink.c:1186
 netlink_sendmsg+0x3b4/0x6e0 net/netlink/af_netlink.c:1857
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:733
 ____sys_sendmsg+0x326/0x4b0 net/socket.c:2573
 ___sys_sendmsg net/socket.c:2627 [inline]
 __sys_sendmsg+0x19d/0x230 net/socket.c:2659
 __do_sys_sendmsg net/socket.c:2664 [inline]
 __se_sys_sendmsg net/socket.c:2662 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2662
 x64_sys_call+0x2734/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:47
 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 0xffffffff88bd8188 of 8 bytes by task 6124 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x168/0x690 kernel/printk/printk.c:2408
 dev_vprintk_emit+0x23c/0x2a0 drivers/base/core.c:4891
 dev_printk_emit+0x82/0xb0 drivers/base/core.c:4902
 __dev_printk+0xf6/0x110 drivers/base/core.c:4914
 _dev_err+0x99/0xc0 drivers/base/core.c:4957
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:599 [inline]
 raw_ioctl+0x1a1e/0x1d70 drivers/usb/gadget/legacy/raw_gadget.c:1306
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:892
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:892
 x64_sys_call+0x1690/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:17
 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: 0x00000000ffffe176 -> 0x00000000ffffeee9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6124 Comm: syz.1.1076 Tainted: G        W          6.14.0-rc6-syzkaller-00022-gb7f94fcf5546 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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