================================================================== BUG: KCSAN: data-race in data_push_tail / vsnprintf write to 0xffffffff88eefef1 of 1 bytes by task 8 on cpu 0: vsnprintf+0xe8f/0xed0 lib/vsprintf.c:2723 vscnprintf+0x29/0x80 lib/vsprintf.c:2754 printk_sprint kernel/printk/printk.c:1936 [inline] vprintk_store+0x4c1/0x9c0 kernel/printk/printk.c:2039 vprintk_emit+0xca/0x3e0 kernel/printk/printk.c:2081 vprintk_default+0x22/0x30 kernel/printk/printk.c:2115 vprintk_func+0x11b/0x120 kernel/printk/printk_safe.c:401 printk+0x62/0x82 kernel/printk/printk.c:2146 decode_std_command drivers/net/hamradio/6pack.c:927 [inline] sixpack_decode drivers/net/hamradio/6pack.c:961 [inline] sixpack_receive_buf+0xe9a/0xf90 drivers/net/hamradio/6pack.c:453 tty_ldisc_receive_buf+0xc6/0xf0 drivers/tty/tty_buffer.c:465 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:481 [inline] flush_to_ldisc+0x1c5/0x2c0 drivers/tty/tty_buffer.c:533 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275 worker_thread+0x616/0xa70 kernel/workqueue.c:2421 kthread+0x20b/0x230 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 read to 0xffffffff88eefef0 of 8 bytes by task 2981 on cpu 1: data_make_reusable kernel/printk/printk_ringbuffer.c:587 [inline] data_push_tail+0x125/0x460 kernel/printk/printk_ringbuffer.c:672 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1043 prb_reserve+0x8f0/0xbc0 kernel/printk/printk_ringbuffer.c:1549 vprintk_store+0x3e9/0x9c0 kernel/printk/printk.c:2029 vprintk_emit+0xca/0x3e0 kernel/printk/printk.c:2081 vprintk_default+0x22/0x30 kernel/printk/printk.c:2115 vprintk_func+0x11b/0x120 kernel/printk/printk_safe.c:401 printk+0x62/0x82 kernel/printk/printk.c:2146 decode_std_command drivers/net/hamradio/6pack.c:927 [inline] sixpack_decode drivers/net/hamradio/6pack.c:961 [inline] sixpack_receive_buf+0xe9a/0xf90 drivers/net/hamradio/6pack.c:453 tty_ldisc_receive_buf+0xc6/0xf0 drivers/tty/tty_buffer.c:465 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:481 [inline] flush_to_ldisc+0x1c5/0x2c0 drivers/tty/tty_buffer.c:533 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275 worker_thread+0x616/0xa70 kernel/workqueue.c:2421 kthread+0x20b/0x230 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 2981 Comm: kworker/u4:4 Not tainted 5.12.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc ==================================================================