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tty: vt: Fix soft lockup in fbcon cursor blink timer.

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We are getting somewhat random soft lockups with this signature:

[   86.992215] [<fffffc00080935e0>] el1_irq+0xa0/0x10c
[   86.997082] [<fffffc000841822c>] cursor_timer_handler+0x30/0x54
[   87.002991] [<fffffc000810ec44>] call_timer_fn+0x54/0x1a8
[   87.008378] [<fffffc000810ef88>] run_timer_softirq+0x1c4/0x2bc
[   87.014200] [<fffffc000809077c>] __do_softirq+0x114/0x344
[   87.019590] [<fffffc00080af45c>] irq_exit+0x74/0x98
[   87.024458] [<fffffc00080fac20>] __handle_domain_irq+0x98/0xfc
[   87.030278] [<fffffc000809056c>] 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 <[email protected]>
Cc: [email protected]
Acked-by: Pavel Machek <[email protected]>
Tested-by: Ming Lei <[email protected]>
Acked-by: Scot Doyle <[email protected]>
Tested-by: Henrique de Moraes Holschuh <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
David Daney authored and Greg Kroah-Hartman committed 2016-06-25 10:41:13 -07:00
1 parent 33688abb28
commit 1b45996d2e
1 file changed
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drivers/tty/vt/vt.c
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@@ -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;