From: David Daney Date: Tue, 17 May 2016 18:41:04 +0000 (-0700) Subject: tty: vt: Fix soft lockup in fbcon cursor blink timer. X-Git-Tag: Ubuntu-4.8.0-22.24~992^2~1 X-Git-Url: https://git.proxmox.com/?p=mirror_ubuntu-zesty-kernel.git;a=commitdiff_plain;h=1b45996d2ebf9680ccd0db875fc668aa025f40fd tty: vt: Fix soft lockup in fbcon cursor blink timer. We are getting somewhat random soft lockups with this signature: [ 86.992215] [] el1_irq+0xa0/0x10c [ 86.997082] [] cursor_timer_handler+0x30/0x54 [ 87.002991] [] call_timer_fn+0x54/0x1a8 [ 87.008378] [] run_timer_softirq+0x1c4/0x2bc [ 87.014200] [] __do_softirq+0x114/0x344 [ 87.019590] [] irq_exit+0x74/0x98 [ 87.024458] [] __handle_domain_irq+0x98/0xfc [ 87.030278] [] gic_handle_irq+0x94/0x190 This is caused by the vt visual_init() function calling into fbcon_init() with a vc_cur_blink_ms value of zero. This is a transient condition, as it is later set to a non-zero value. But, if the timer happens to expire while the blink rate is zero, it goes into an endless loop, and we get soft lockup. The fix is to initialize vc_cur_blink_ms before calling the con_init() function. Signed-off-by: David Daney Cc: stable@vger.kernel.org Acked-by: Pavel Machek Tested-by: Ming Lei Acked-by: Scot Doyle Tested-by: Henrique de Moraes Holschuh Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index dc125322f48f..5b0fe97c46ca 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -750,6 +750,7 @@ static void visual_init(struct vc_data *vc, int num, int init) vc->vc_complement_mask = 0; vc->vc_can_do_color = 0; vc->vc_panic_force_write = false; + vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS; vc->vc_sw->con_init(vc, init); if (!vc->vc_complement_mask) vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;