rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=402/1/0x4000000000000000 softirq=103426/103427 fqs=5233 (t=10501 jiffies g=188617 q=1397) NMI backtrace for cpu 1 CPU: 1 PID: 5204 Comm: syz-executor.3 Not tainted 5.13.0-rc2-next-20210518-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x13e/0x1d6 lib/dump_stack.c:129 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:342 print_cpu_stall kernel/rcu/tree_stall.h:625 [inline] check_cpu_stall kernel/rcu/tree_stall.h:700 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq.cold+0x3f1/0x74b kernel/rcu/tree.c:2641 update_process_times+0x16d/0x200 kernel/time/timer.c:1782 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1420 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647 RIP: 0010:slow_down_io arch/x86/include/asm/paravirt.h:55 [inline] RIP: 0010:inb_p arch/x86/include/asm/io.h:334 [inline] RIP: 0010:vga_io_r include/video/vga.h:204 [inline] RIP: 0010:vga_io_rgfx include/video/vga.h:389 [inline] RIP: 0010:setcolor drivers/video/fbdev/vga16fb.c:170 [inline] RIP: 0010:vga_imageblit_expand drivers/video/fbdev/vga16fb.c:1164 [inline] RIP: 0010:vga16fb_imageblit+0x929/0x2200 drivers/video/fbdev/vga16fb.c:1260 Code: c7 c2 a0 01 ff 8b 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 b2 15 00 00 ff 15 5d cd f5 07 ba cf 03 00 00 ec <48> c7 c2 a0 01 ff 8b 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 RSP: 0018:ffffc90002986e50 EFLAGS: 00000246 RAX: dffffc00000000ff RBX: 0000000000000000 RCX: ffffc90015dea000 RDX: 00000000000003cf RSI: ffffffff84093270 RDI: ffffc90002986fe8 RBP: ffffc90002986fdc R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff84093263 R11: 0000000000000001 R12: ffffffff81329c30 R13: ffff88801b714eee R14: ffffc90002986ff8 R15: ffffc90002986fd8 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:139 [inline] bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:188 fbcon_putcs+0x35a/0x450 drivers/video/fbdev/core/fbcon.c:1296 fbcon_redraw.constprop.0+0x41a/0x4b0 drivers/video/fbdev/core/fbcon.c:1672 fbcon_scroll+0x1d7a/0x3580 drivers/video/fbdev/core/fbcon.c:1782 con_scroll+0x5b9/0x6d0 drivers/tty/vt/vt.c:630 lf+0x26b/0x2c0 drivers/tty/vt/vt.c:1490 vc_con_write_normal drivers/tty/vt/vt.c:2811 [inline] do_con_write+0xf1c/0x1e40 drivers/tty/vt/vt.c:2915 con_put_char+0x70/0xa0 drivers/tty/vt/vt.c:3263 tty_put_char+0xb7/0x150 drivers/tty/tty_io.c:3180 do_output_char+0x155/0x850 drivers/tty/n_tty.c:485 process_output drivers/tty/n_tty.c:511 [inline] n_tty_write+0x4c3/0xfd0 drivers/tty/n_tty.c:2300 do_tty_write drivers/tty/tty_io.c:1042 [inline] file_tty_write.constprop.0+0x526/0x910 drivers/tty/tty_io.c:1131 call_write_iter include/linux/fs.h:2114 [inline] do_iter_readv_writev+0x46f/0x740 fs/read_write.c:740 do_iter_write+0x188/0x670 fs/read_write.c:866 vfs_iter_write+0x70/0xa0 fs/read_write.c:907 iter_file_splice_write+0x723/0xc70 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x110/0x180 fs/splice.c:936 splice_direct_to_actor+0x34b/0x8c0 fs/splice.c:891 do_splice_direct+0x1b3/0x280 fs/splice.c:979 do_sendfile+0x9f0/0x1120 fs/read_write.c:1260 __do_sys_sendfile64 fs/read_write.c:1325 [inline] __se_sys_sendfile64 fs/read_write.c:1311 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1311 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd84f3c9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 000000000056c0f0 RCX: 00000000004665d9 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000007 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0800000080004103 R11: 0000000000000246 R12: 000000000056c0f0 R13: 00007ffe40adce2f R14: 00007fd84f3c9300 R15: 0000000000022000