copy_to_user include/linux/uaccess.h:225 [inline] simple_read_from_buffer+0xb2/0x130 fs/libfs.c:1121 proc_fail_nth_read+0x103/0x140 fs/proc/base.c:1482 ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff86871760 of 8 bytes by task 9269 on cpu 1: data_alloc+0x290/0x2c0 kernel/printk/printk_ringbuffer.c:1096 prb_reserve+0x86a/0xb80 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x7f/0xb0 kernel/printk/printk.c:2475 caif_netlink_parms net/caif/chnl_net.c:424 [inline] ipcaif_newlink+0x163/0x2e0 net/caif/chnl_net.c:450 rtnl_newlink_create+0x1bb/0x640 net/core/rtnetlink.c:3830 __rtnl_newlink net/core/rtnetlink.c:3947 [inline] rtnl_newlink+0xf38/0x12d0 net/core/rtnetlink.c:4062 rtnetlink_rcv_msg+0x65a/0x740 net/core/rtnetlink.c:6952 netlink_rcv_skb+0x12f/0x230 net/netlink/af_netlink.c:2534 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6979 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x605/0x6c0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x609/0x720 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x140/0x180 net/socket.c:727 __sys_sendto+0x1aa/0x230 net/socket.c:2180 __do_sys_sendto net/socket.c:2187 [inline] __se_sys_sendto net/socket.c:2183 [inline] __x64_sys_sendto+0x78/0x90 net/socket.c:2183 x64_sys_call+0x2bcb/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff86871760 of 8 bytes by task 9305 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+0x239/0xb80 kernel/printk/printk_ringbuffer.c:1619 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x7f/0xb0 kernel/printk/printk.c:2475 printk_stack_address arch/x86/kernel/dumpstack.c:72 [inline] show_trace_log_lvl+0x382/0x410 arch/x86/kernel/dumpstack.c:285 __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xf6/0x150 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+0x261/0x270 lib/fault-inject.c:174 should_fail+0xb/0x10 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+0xb2/0x130 fs/libfs.c:1121 proc_fail_nth_read+0x103/0x140 fs/proc/base.c:1482 vfs_read+0x1b2/0x710 fs/read_write.c:568 ksys_read+0xeb/0x1b0 fs/read_write.c:713 __do_sys_read fs/read_write.c:722 [inline] __se_sys_read fs/read_write.c:720 [inline] __x64_sys_read+0x42/0x50 fs/read_write.c:720 x64_sys_call+0x2a3b/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:1 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x0000000000085cd0 -> 0x0000000000137228 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 9305 Comm: syz.3.13105 Not tainted 6.14.0-syzkaller-09584-g7d06015d936c #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 ================================================================== vfs_read+0x1b2/0x710 fs/read_write.c:568 ksys_read+0xeb/0x1b0 fs/read_write.c:713 __do_sys_read fs/read_write.c:722 [inline] __se_sys_read fs/read_write.c:720 [inline] __x64_sys_read+0x42/0x50 fs/read_write.c:720 x64_sys_call+0x2a3b/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:1 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f356630bb7c 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:00007f356496f030 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f3566525fa0 RCX: 00007f356630bb7c RDX: 000000000000000f RSI: 00007f356496f0a0 RDI: 0000000000000003 RBP: 00007f356496f090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 00007f3566525fa0 R15: 00007ffe55416488