alloc_empty_file+0x70/0x1e0 fs/file_table.c:262 alloc_file fs/file_table.c:396 [inline] alloc_file_pseudo+0x92/0x120 fs/file_table.c:427 sock_alloc_file+0x9c/0x1e0 net/socket.c:532 sock_map_fd net/socket.c:562 [inline] __sys_socket+0x118/0x180 net/socket.c:1802 __do_sys_socket net/socket.c:1807 [inline] __se_sys_socket net/socket.c:1805 [inline] __x64_sys_socket+0x3f/0x50 net/socket.c:1805 ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff86c6abc0 of 8 bytes by task 1865 on cpu 1: data_alloc+0x308/0x380 kernel/printk/printk_ringbuffer.c:1130 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 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 __ext4_msg+0x1aa/0x1c0 fs/ext4/super.c:1001 ext4_put_super+0x90/0x7c0 fs/ext4/super.c:1302 generic_shutdown_super+0xee/0x220 fs/super.c:647 kill_block_super+0x2a/0x70 fs/super.c:1665 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7499 deactivate_locked_super+0x75/0x1c0 fs/super.c:477 deactivate_super+0x97/0xa0 fs/super.c:510 cleanup_mnt+0x2c3/0x340 fs/namespace.c:1317 __cleanup_mnt+0x19/0x20 fs/namespace.c:1324 task_work_run+0x130/0x1a0 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff86c6abc0 of 8 bytes by task 8615 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:792 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:938 [inline] prb_reserve+0x21a/0xaf0 kernel/printk/printk_ringbuffer.c:1677 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 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 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] __show_trace_log_lvl+0x460/0x560 arch/x86/kernel/dumpstack.c:282 __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:73 [inline] should_fail_ex+0x25e/0x270 lib/fault-inject.c:174 should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4567 [inline] slab_alloc_node mm/slub.c:4925 [inline] kmem_cache_alloc_noprof+0x7f/0x3c0 mm/slub.c:4959 alloc_empty_file+0x70/0x1e0 fs/file_table.c:262 alloc_file fs/file_table.c:396 [inline] alloc_file_pseudo+0x92/0x120 fs/file_table.c:427 sock_alloc_file+0x9c/0x1e0 net/socket.c:532 sock_map_fd net/socket.c:562 [inline] __sys_socket+0x118/0x180 net/socket.c:1802 __do_sys_socket net/socket.c:1807 [inline] __se_sys_socket net/socket.c:1805 [inline] __x64_sys_socket+0x3f/0x50 net/socket.c:1805 x64_sys_call+0x11fc/0x3020 arch/x86/include/generated/asm/syscalls_64.h:42 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: 0x0000000000139a78 -> 0x00000000001f5380 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 8615 Comm: syz.9.10946 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 ================================================================== x64_sys_call+0x11fc/0x3020 arch/x86/include/generated/asm/syscalls_64.h:42 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 RIP: 0033:0x7f6f47b8de99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6f465e7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 00007f6f47e15fa0 RCX: 00007f6f47b8de99 RDX: 0000000000000009 RSI: 0000000000000003 RDI: 0000000000000010 RBP: 00007f6f465e7090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f6f47e16038 R14: 00007f6f47e15fa0 R15: 00007ffdde280c48