* [PATCH] fbcon: Avoid deleting a timer in IRQ context
@ 2015-05-21 7:58 Thierry Reding
2015-05-27 11:19 ` Andrey Wagin
2015-05-27 12:39 ` Thierry Reding
0 siblings, 2 replies; 4+ messages in thread
From: Thierry Reding @ 2015-05-21 7:58 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Kevin Hilman, Scot Doyle, Daniel Stone,
Jean-Christophe Plagniol-Villard, Tomi Valkeinen, linux-fbdev,
linux-kernel
From: Thierry Reding <treding@nvidia.com>
Commit 27a4c827c34a ("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: Daniel Stone <daniel@fooishbar.org>
Reported-by: Kevin Hilman <khilman@kernel.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/video/console/fbcon.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 05b1d1a71ef9..658c34bb9076 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -1310,8 +1310,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
return;
ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
- fbcon_del_cursor_timer(info);
- if (!(vc->vc_cursor_type & 0x10))
+ if (vc->vc_cursor_type & 0x10)
+ fbcon_del_cursor_timer(info);
+ else
fbcon_add_cursor_timer(info);
ops->cursor_flash = (mode = CM_ERASE) ? 0 : 1;
--
2.4.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] fbcon: Avoid deleting a timer in IRQ context
2015-05-21 7:58 [PATCH] fbcon: Avoid deleting a timer in IRQ context Thierry Reding
@ 2015-05-27 11:19 ` Andrey Wagin
2015-05-27 12:10 ` Tomeu Vizoso
2015-05-27 12:39 ` Thierry Reding
1 sibling, 1 reply; 4+ messages in thread
From: Andrey Wagin @ 2015-05-27 11:19 UTC (permalink / raw)
To: Thierry Reding
Cc: Greg Kroah-Hartman, Kevin Hilman, Scot Doyle, Daniel Stone,
Jean-Christophe Plagniol-Villard, Tomi Valkeinen, linux-fbdev,
LKML
2015-05-21 10:58 GMT+03:00 Thierry Reding <thierry.reding@gmail.com>:
> From: Thierry Reding <treding@nvidia.com>
>
> Commit 27a4c827c34a ("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.
Tested-by: Andrew Vagin <avagin@virtuozzo.com>
It would be good to push this patch into linux-next asap. Without this
patch I can't execute tests on linux-next. Thanks.
>
> Reported-by: Daniel Stone <daniel@fooishbar.org>
> Reported-by: Kevin Hilman <khilman@kernel.org>
> Tested-by: Kevin Hilman <khilman@linaro.org>
> Tested-by: Scot Doyle <lkml14@scotdoyle.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
> drivers/video/console/fbcon.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
> index 05b1d1a71ef9..658c34bb9076 100644
> --- a/drivers/video/console/fbcon.c
> +++ b/drivers/video/console/fbcon.c
> @@ -1310,8 +1310,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
> return;
>
> ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
> - fbcon_del_cursor_timer(info);
> - if (!(vc->vc_cursor_type & 0x10))
> + if (vc->vc_cursor_type & 0x10)
> + fbcon_del_cursor_timer(info);
> + else
> fbcon_add_cursor_timer(info);
>
> ops->cursor_flash = (mode = CM_ERASE) ? 0 : 1;
> --
> 2.4.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] fbcon: Avoid deleting a timer in IRQ context
2015-05-27 11:19 ` Andrey Wagin
@ 2015-05-27 12:10 ` Tomeu Vizoso
0 siblings, 0 replies; 4+ messages in thread
From: Tomeu Vizoso @ 2015-05-27 12:10 UTC (permalink / raw)
To: Andrey Wagin
Cc: Thierry Reding, Greg Kroah-Hartman, Kevin Hilman, Scot Doyle,
Daniel Stone, Jean-Christophe Plagniol-Villard, Tomi Valkeinen,
linux-fbdev, LKML
On 27 May 2015 at 13:19, Andrey Wagin <avagin@gmail.com> wrote:
> 2015-05-21 10:58 GMT+03:00 Thierry Reding <thierry.reding@gmail.com>:
>> From: Thierry Reding <treding@nvidia.com>
>>
>> Commit 27a4c827c34a ("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.
>
> Tested-by: Andrew Vagin <avagin@virtuozzo.com>
>
> It would be good to push this patch into linux-next asap. Without this
> patch I can't execute tests on linux-next. Thanks.
Tested-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Same here, please apply.
Thanks,
Tomeu
>>
>> Reported-by: Daniel Stone <daniel@fooishbar.org>
>> Reported-by: Kevin Hilman <khilman@kernel.org>
>> Tested-by: Kevin Hilman <khilman@linaro.org>
>> Tested-by: Scot Doyle <lkml14@scotdoyle.com>
>> Signed-off-by: Thierry Reding <treding@nvidia.com>
>> ---
>> drivers/video/console/fbcon.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
>> index 05b1d1a71ef9..658c34bb9076 100644
>> --- a/drivers/video/console/fbcon.c
>> +++ b/drivers/video/console/fbcon.c
>> @@ -1310,8 +1310,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
>> return;
>>
>> ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
>> - fbcon_del_cursor_timer(info);
>> - if (!(vc->vc_cursor_type & 0x10))
>> + if (vc->vc_cursor_type & 0x10)
>> + fbcon_del_cursor_timer(info);
>> + else
>> fbcon_add_cursor_timer(info);
>>
>> ops->cursor_flash = (mode = CM_ERASE) ? 0 : 1;
>> --
>> 2.4.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] fbcon: Avoid deleting a timer in IRQ context
2015-05-21 7:58 [PATCH] fbcon: Avoid deleting a timer in IRQ context Thierry Reding
2015-05-27 11:19 ` Andrey Wagin
@ 2015-05-27 12:39 ` Thierry Reding
1 sibling, 0 replies; 4+ messages in thread
From: Thierry Reding @ 2015-05-27 12:39 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Kevin Hilman, Scot Doyle, Daniel Stone,
Jean-Christophe Plagniol-Villard, Tomi Valkeinen, linux-fbdev,
linux-kernel
[-- Attachment #1: Type: text/plain, Size: 3394 bytes --]
On Thu, May 21, 2015 at 09:58:03AM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
>
> Commit 27a4c827c34a ("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: Daniel Stone <daniel@fooishbar.org>
> Reported-by: Kevin Hilman <khilman@kernel.org>
> Tested-by: Kevin Hilman <khilman@linaro.org>
> Tested-by: Scot Doyle <lkml14@scotdoyle.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
> drivers/video/console/fbcon.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
Ping? This is an important fix, can we get this into linux-next sometime
soon?
Thierry
>
> diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
> index 05b1d1a71ef9..658c34bb9076 100644
> --- a/drivers/video/console/fbcon.c
> +++ b/drivers/video/console/fbcon.c
> @@ -1310,8 +1310,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
> return;
>
> ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
> - fbcon_del_cursor_timer(info);
> - if (!(vc->vc_cursor_type & 0x10))
> + if (vc->vc_cursor_type & 0x10)
> + fbcon_del_cursor_timer(info);
> + else
> fbcon_add_cursor_timer(info);
>
> ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
> --
> 2.4.1
>
[-- Attachment #2: Type: application/pgp-signature, Size: 819 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-05-27 12:39 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-05-21 7:58 [PATCH] fbcon: Avoid deleting a timer in IRQ context Thierry Reding
2015-05-27 11:19 ` Andrey Wagin
2015-05-27 12:10 ` Tomeu Vizoso
2015-05-27 12:39 ` Thierry Reding
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).