FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff8687d980 of 8 bytes by task 31465 on cpu 1: data_alloc+0x27d/0x2b0 kernel/printk/printk_ringbuffer.c:1096 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 logfc+0x2cb/0x2e0 fs/fs_context.c:-1 vfs_parse_fs_param+0x1e0/0x2a0 fs/fs_context.c:158 vfs_parse_fs_string fs/fs_context.c:188 [inline] vfs_parse_monolithic_sep+0x18a/0x200 fs/fs_context.c:230 generic_parse_monolithic+0x24/0x30 fs/fs_context.c:258 parse_monolithic_mount_data+0x43/0x60 fs/fs_context.c:723 do_new_mount+0x1da/0x5e0 fs/namespace.c:3804 path_mount+0x4a4/0xb20 fs/namespace.c:4123 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4324 __x64_sys_mount+0x67/0x80 fs/namespace.c:4324 x64_sys_call+0x2b4d/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:166 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff8687d980 of 8 bytes by task 31468 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:482 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:778 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:924 [inline] prb_reserve+0x221/0xaf0 kernel/printk/printk_ringbuffer.c:1619 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 dump_stack_print_info+0xee/0x1b0 lib/dump_stack.c:57 __dump_stack+0x11/0x30 lib/dump_stack.c:93 dump_stack_lvl+0xe8/0x140 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+0x265/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37 _inline_copy_to_user include/linux/uaccess.h:193 [inline] _copy_to_user+0x20/0xa0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:225 [inline] simple_read_from_buffer+0xb5/0x130 fs/libfs.c:1135 proc_fail_nth_read+0x10e/0x150 fs/proc/base.c:1488 vfs_read+0x1a5/0x770 fs/read_write.c:570 ksys_read+0xda/0x1a0 fs/read_write.c:715 __do_sys_read fs/read_write.c:724 [inline] __se_sys_read fs/read_write.c:722 [inline] __x64_sys_read+0x40/0x50 fs/read_write.c:722 x64_sys_call+0x27bc/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:1 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000000af438 -> 0x0000000000146ab8 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 31468 Comm: syz.6.7914 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 ================================================================== CPU: 0 UID: 0 PID: 31468 Comm: syz.6.7914 Tainted: [W]=WARN syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 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+0x265/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37 _inline_copy_to_user include/linux/uaccess.h:193 [inline] _copy_to_user+0x20/0xa0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:225 [inline] simple_read_from_buffer+0xb5/0x130 fs/libfs.c:1135 proc_fail_nth_read+0x10e/0x150 fs/proc/base.c:1488 vfs_read+0x1a5/0x770 fs/read_write.c:570 ksys_read+0xda/0x1a0 fs/read_write.c:715 __do_sys_read fs/read_write.c:724 [inline] __se_sys_read fs/read_write.c:722 [inline] __x64_sys_read+0x40/0x50 fs/read_write.c:722 x64_sys_call+0x27bc/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:1 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9eada1d5bc Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 99 93 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 ef 93 02 00 48 RSP: 002b:00007f9eac487030 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f9eadc65fa0 RCX: 00007f9eada1d5bc RDX: 000000000000000f RSI: 00007f9eac4870a0 RDI: 0000000000000003 RBP: 00007f9eac487090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f9eadc66038 R14: 00007f9eadc65fa0 R15: 00007fff9ff98f48