1. 31 May, 2015 9 commits
  2. 27 May, 2015 1 commit
    • Thierry Reding's avatar
      fbcon: Avoid deleting a timer in IRQ context · a5edce42
      Thierry Reding authored
      Commit 27a4c827 ("fbcon: use the cursor blink interval provided by
      vt") unconditionally removes the cursor blink timer. Unfortunately that
      wreaks havoc under some circumstances. An easily reproducible way is to
      use both the framebuffer console and a debug serial port as the console
      output for kernel messages (e.g. "console=ttyS0 console=tty1" on the
      kernel command-line. Upon boot this triggers a warning from within the
      del_timer_sync() function because it is called from IRQ context:
      
      	[    5.070096] ------------[ cut here ]------------
      	[    5.070110] WARNING: CPU: 0 PID: 0 at ../kernel/time/timer.c:1098 del_timer_sync+0x4c/0x54()
      	[    5.070115] Modules linked in:
      	[    5.070120] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.0-rc4-next-20150519 #1
      	[    5.070123] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
      	[    5.070142] [] (unwind_backtrace) from [] (show_stack+0x10/0x14)
      	[    5.070156] [] (show_stack) from [] (dump_stack+0x70/0xbc)
      	[    5.070164] [] (dump_stack) from [] (warn_slowpath_common+0x74/0xb0)
      	[    5.070169] [] (warn_slowpath_common) from [] (warn_slowpath_null+0x1c/0x24)
      	[    5.070174] [] (warn_slowpath_null) from [] (del_timer_sync+0x4c/0x54)
      	[    5.070183] [] (del_timer_sync) from [] (fbcon_del_cursor_timer+0x2c/0x40)
      	[    5.070190] [] (fbcon_del_cursor_timer) from [] (fbcon_cursor+0x9c/0x180)
      	[    5.070198] [] (fbcon_cursor) from [] (hide_cursor+0x30/0x98)
      	[    5.070204] [] (hide_cursor) from [] (vt_console_print+0x2a8/0x340)
      	[    5.070212] [] (vt_console_print) from [] (call_console_drivers.constprop.23+0xc8/0xec)
      	[    5.070218] [] (call_console_drivers.constprop.23) from [] (console_unlock+0x498/0x4f0)
      	[    5.070223] [] (console_unlock) from [] (vprintk_emit+0x1f0/0x508)
      	[    5.070228] [] (vprintk_emit) from [] (vprintk_default+0x24/0x2c)
      	[    5.070234] [] (vprintk_default) from [] (printk+0x70/0x88)
      
      After which the system starts spewing all kinds of weird and seemingly
      unrelated error messages.
      
      This commit fixes this by restoring the condition under which the call
      to fbcon_del_cursor_timer() happens.
      Reported-by: default avatarDaniel Stone <daniel@fooishbar.org>
      Reported-by: default avatarKevin Hilman <khilman@kernel.org>
      Tested-by: default avatarKevin Hilman <khilman@linaro.org>
      Tested-by: default avatarScot Doyle <lkml14@scotdoyle.com>
      Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
      Tested-by: default avatarAndrew Vagin <avagin@virtuozzo.com>
      Tested-by: default avatarTomeu Vizoso <tomeu.vizoso@collabora.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a5edce42
  3. 24 May, 2015 30 commits