R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fbbd4416038 R14: 00007fbbd4415fa0 R15: 00007ffdf2c428f8
 </TASK>
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff895fb678 of 43 bytes by task 8829 on cpu 1:
 vsnprintf+0x2c0/0x8c0 lib/vsprintf.c:2899
 vscnprintf+0x41/0x90 lib/vsprintf.c:3017
 printk_sprint+0x30/0x2b0 kernel/printk/printk.c:2222
 vprintk_store+0x57f/0x910 kernel/printk/printk.c:2364
 vprintk_emit+0x1a4/0x580 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 fail_dump lib/fault-inject.c:67 [inline]
 should_fail_ex+0x241/0x270 lib/fault-inject.c:175
 should_failslab+0x8c/0xb0 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4675 [inline]
 slab_alloc_node mm/slub.c:5011 [inline]
 kmem_cache_alloc_noprof+0x5e/0x3d0 mm/slub.c:5047
 anon_vma_chain_alloc mm/rmap.c:142 [inline]
 anon_vma_clone+0x14f/0x550 mm/rmap.c:344
 anon_vma_fork+0x15e/0x410 mm/rmap.c:406
 dup_mmap+0x547/0x1120 mm/mmap.c:1781
 dup_mm kernel/fork.c:1542 [inline]
 copy_mm+0xf5/0x340 kernel/fork.c:1594
 copy_process+0x10e9/0x2400 kernel/fork.c:2320
 kernel_clone+0x1c0/0x5f0 kernel/fork.c:2790
 __do_sys_clone3 kernel/fork.c:3093 [inline]
 __se_sys_clone3+0x1f5/0x230 kernel/fork.c:3072
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:3072
 x64_sys_call+0x437/0x2550 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff895fb678 of 8 bytes by task 8831 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:607 [inline]
 data_push_tail+0x104/0x440 kernel/printk/printk_ringbuffer.c:692
 data_alloc+0x111/0x380 kernel/printk/printk_ringbuffer.c:1088
 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1725
 vprintk_store+0x54e/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x580 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 __show_trace_log_lvl+0x48b/0x560 arch/x86/kernel/dumpstack.c:302
 __dump_stack+0x1d/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120
 dump_stack+0x15/0x1b lib/dump_stack.c:129
 fail_dump lib/fault-inject.c:74 [inline]
 should_fail_ex+0x259/0x270 lib/fault-inject.c:175
 should_failslab+0x8c/0xb0 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4675 [inline]
 slab_alloc_node mm/slub.c:5011 [inline]
 kmem_cache_alloc_noprof+0x5e/0x3d0 mm/slub.c:5047
 prepare_creds+0x38/0x550 kernel/cred.c:185
 __do_sys_capset kernel/capability.c:247 [inline]
 __se_sys_capset+0x2da/0x480 kernel/capability.c:216
 __x64_sys_capset+0x31/0x40 kernel/capability.c:216
 x64_sys_call+0x1515/0x2550 arch/x86/include/generated/asm/syscalls_64.h:127
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x3fffffffffffee6d -> 0x4e495f544c554146

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8831 Comm: syz.3.1571 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
==================================================================