fbcon: Avoid deleting a timer in IRQ context
Subsystems (2)
PATCH 1/1 fbcon: Avoid deleting a timer in IRQ context
From: Thierry Reding <[email protected]>
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.
--- drivers/video/console/fbcon.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
drivers/video/console/fbcon.c +3 -2
@@ -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 ;
Signature · 1 line
2.4.1
2015-05-21 10:58 GMT+03:00 Thierry Reding <[email protected]>:
Quoted 30 lines
From: Thierry Reding <[email protected]>
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 thedel_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)
Quoted 5 lines
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.
It would be good to push this patch into linux-next asap. Without this patch I can't execute tests on linux-next. Thanks.
Quoted 34 lines
Reported-by Daniel Stone <[email protected]>Reported-by Kevin Hilman <[email protected]>Tested-by Kevin Hilman <[email protected]>Tested-by Scot Doyle <[email protected]>Signed-off-by Thierry Reding <[email protected]>--- drivers/video/console/fbcon.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)drivers/video/console/fbcon.c +3
-3@@ -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
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Tomeu Vizoso
Tested-byQuoted 34 lines · Andrey Wagin
2015-05-21 10:58 GMT+03:00 Thierry Reding <[email protected]>:
Quoted 33 lines
From: Thierry Reding <[email protected]>
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 thedel_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.
Quoted 7 lines
Quoted 2 lines
This commit fixes this by restoring the condition under which the call to
fbcon_del_cursor_timer()happens.Tested-by Andrew Vagin <[email protected]>It would be good to push this patch into linux-next asap. Without this patch I can't execute tests on linux-next. Thanks.
Same here, please apply.
Thanks,
Tomeu
Quoted 39 lines
Quoted 29 lines
Reported-by Daniel Stone <[email protected]>Reported-by Kevin Hilman <[email protected]>Tested-by Kevin Hilman <[email protected]>Tested-by Scot Doyle <[email protected]>Signed-off-by Thierry Reding <[email protected]>--- drivers/video/console/fbcon.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)drivers/video/console/fbcon.c +3
-3@@ -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
Quoted 5 lines
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Quoted 36 lines · Thierry Reding
From: Thierry Reding <[email protected]>
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 thedel_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.
Quoted 8 lines
Reported-by Daniel Stone <[email protected]>Reported-by Kevin Hilman <[email protected]>Tested-by Kevin Hilman <[email protected]>Tested-by Scot Doyle <[email protected]>Signed-off-by Thierry Reding <[email protected]>--- 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
Quoted 20 lines
drivers/video/console/fbcon.c +3
-2@@ -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 ;Signature · 1 line
2.4.1