FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff88e117f8 of 8 bytes by task 29257 on cpu 0:
 data_alloc+0x203/0x2b0 kernel/printk/printk_ringbuffer.c:1082
 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
 __ext4_msg+0x135/0x1a0 fs/ext4/super.c:983
 ext4_parse_param+0x252/0xf10 fs/ext4/super.c:2180
 vfs_parse_fs_param+0x13f/0x2a0 fs/fs_context.c:146
 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+0x46/0x60 fs/fs_context.c:723
 do_new_mount+0x1da/0x5e0 fs/namespace.c:3801
 path_mount+0x4a4/0xb20 fs/namespace.c:4120
 do_mount fs/namespace.c:4133 [inline]
 __do_sys_mount fs/namespace.c:4344 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4321
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4321
 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 0xffffffff88e117f8 of 8 bytes by task 29259 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 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
 fail_dump lib/fault-inject.c:66 [inline]
 should_fail_ex+0x24d/0x280 lib/fault-inject.c:174
 should_failslab+0x8c/0xb0 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4101 [inline]
 slab_alloc_node mm/slub.c:4177 [inline]
 kmem_cache_alloc_lru_noprof+0x55/0x310 mm/slub.c:4216
 __d_alloc+0x3d/0x340 fs/dcache.c:1690
 d_alloc_anon+0x17/0x20 fs/dcache.c:1787
 prepare_anon_dentry fs/libfs.c:2181 [inline]
 path_from_stashed+0x1cf/0x330 fs/libfs.c:2249
 pidfs_alloc_file+0xa2/0x180 fs/pidfs.c:1049
 pidfd_prepare+0xc9/0x130 kernel/fork.c:1848
 pidfd_create kernel/pid.c:623 [inline]
 __do_sys_pidfd_open kernel/pid.c:659 [inline]
 __se_sys_pidfd_open+0x133/0x270 kernel/pid.c:644
 __x64_sys_pidfd_open+0x31/0x40 kernel/pid.c:644
 x64_sys_call+0x2adf/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:435
 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: 0x00000001000082a9 -> 0x0000000100008fb2

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 29259 Comm: syz.5.19503 Tainted: G        W           6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
CPU: 1 UID: 0 PID: 29259 Comm: syz.5.19503 Tainted: G        W           6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __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_failslab+0x8c/0xb0 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4101 [inline]
 slab_alloc_node mm/slub.c:4177 [inline]
 kmem_cache_alloc_lru_noprof+0x55/0x310 mm/slub.c:4216
 __d_alloc+0x3d/0x340 fs/dcache.c:1690
 d_alloc_anon+0x17/0x20 fs/dcache.c:1787
 prepare_anon_dentry fs/libfs.c:2181 [inline]
 path_from_stashed+0x1cf/0x330 fs/libfs.c:2249
 pidfs_alloc_file+0xa2/0x180 fs/pidfs.c:1049
 pidfd_prepare+0xc9/0x130 kernel/fork.c:1848
 pidfd_create kernel/pid.c:623 [inline]
 __do_sys_pidfd_open kernel/pid.c:659 [inline]
 __se_sys_pidfd_open+0x133/0x270 kernel/pid.c:644
 __x64_sys_pidfd_open+0x31/0x40 kernel/pid.c:644
 x64_sys_call+0x2adf/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:435
 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: 0033:0x7f0958e9e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0957507028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b2
RAX: ffffffffffffffda RBX: 00007f09590c5fa0 RCX: 00007f0958e9e9a9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000039c
RBP: 00007f0957507090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f09590c5fa0 R15: 00007ffdd6c293a8
 </TASK>