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    tty: vt: Fix soft lockup in fbcon cursor blink timer. · 1b45996d
    David Daney 提交于
    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: NDavid Daney <david.daney@cavium.com>
    Cc: stable@vger.kernel.org
    Acked-by: NPavel Machek <pavel@ucw.cz>
    Tested-by: NMing Lei <ming.lei@canonical.com>
    Acked-by: NScot Doyle <lkml14@scotdoyle.com>
    Tested-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    1b45996d
vt.c 103.0 KB