| Message ID | 1414177592-14547-1-git-send-email-johan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > Remove redundant local_irq_disable() at machine halt and restart. > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > smp_send_stop()") interrupts are disabled before stopping secondary > CPUs. Assuming this is correct, you should have: Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) Cc: <stable@vger.kernel.org> # v3.12+ > Signed-off-by: Johan Hovold <johan@kernel.org> > --- > arch/arm/kernel/process.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > index a35f6ebbd2c2..5663ab57cf07 100644 > --- a/arch/arm/kernel/process.c > +++ b/arch/arm/kernel/process.c > @@ -195,7 +195,6 @@ void machine_halt(void) > local_irq_disable(); > smp_send_stop(); > > - local_irq_disable(); > while (1); > } > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > /* Whoops - the platform was unable to reboot. Tell the user! */ > printk("Reboot failed -- System halted\n"); > - local_irq_disable(); ... but wouldn't this reintroduce the the buck which that commit fixed ?
On Fri, Oct 24, 2014 at 02:16:27PM -0500, Felipe Balbi wrote: > On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > > Remove redundant local_irq_disable() at machine halt and restart. > > > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > > smp_send_stop()") interrupts are disabled before stopping secondary > > CPUs. > > Assuming this is correct, you should have: > > Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) > Cc: <stable@vger.kernel.org> # v3.12+ > > > Signed-off-by: Johan Hovold <johan@kernel.org> > > --- > > arch/arm/kernel/process.c | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > > index a35f6ebbd2c2..5663ab57cf07 100644 > > --- a/arch/arm/kernel/process.c > > +++ b/arch/arm/kernel/process.c > > @@ -195,7 +195,6 @@ void machine_halt(void) > > local_irq_disable(); > > smp_send_stop(); > > > > - local_irq_disable(); > > while (1); > > } > > > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > > > /* Whoops - the platform was unable to reboot. Tell the user! */ > > printk("Reboot failed -- System halted\n"); > > - local_irq_disable(); > > ... but wouldn't this reintroduce the the buck which that commit fixed ? s/buck/bug :-) my fingers have a mind of their own, aparently.
On Fri, Oct 24, 2014 at 02:21:11PM -0500, Felipe Balbi wrote: > On Fri, Oct 24, 2014 at 02:16:27PM -0500, Felipe Balbi wrote: > > On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > > > Remove redundant local_irq_disable() at machine halt and restart. > > > > > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > > > smp_send_stop()") interrupts are disabled before stopping secondary > > > CPUs. > > > > Assuming this is correct, you should have: > > > > Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) > > Cc: <stable@vger.kernel.org> # v3.12+ It's not a bug. Just a redundant disabling of already disabled interrupts, something which could possibly lead someone to believe that interrupts could be re-enabled by the power-off handler. And if that was the case, wouldn't that introduce the bug that 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with smp_send_stop()") was trying to fix? > > > Signed-off-by: Johan Hovold <johan@kernel.org> > > > --- > > > arch/arm/kernel/process.c | 2 -- > > > 1 file changed, 2 deletions(-) > > > > > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > > > index a35f6ebbd2c2..5663ab57cf07 100644 > > > --- a/arch/arm/kernel/process.c > > > +++ b/arch/arm/kernel/process.c > > > @@ -195,7 +195,6 @@ void machine_halt(void) > > > local_irq_disable(); > > > smp_send_stop(); > > > > > > - local_irq_disable(); > > > while (1); > > > } > > > > > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > > > > > /* Whoops - the platform was unable to reboot. Tell the user! */ > > > printk("Reboot failed -- System halted\n"); > > > - local_irq_disable(); > > > > ... but wouldn't this reintroduce the the buck which that commit fixed ? > > s/buck/bug :-) my fingers have a mind of their own, aparently. :) No, the interrupts would still be disabled. Thanks, Johan
On Fri, Oct 24, 2014 at 09:28:45PM +0200, Johan Hovold wrote: > On Fri, Oct 24, 2014 at 02:21:11PM -0500, Felipe Balbi wrote: > > On Fri, Oct 24, 2014 at 02:16:27PM -0500, Felipe Balbi wrote: > > > On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > > > > Remove redundant local_irq_disable() at machine halt and restart. > > > > > > > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > > > > smp_send_stop()") interrupts are disabled before stopping secondary > > > > CPUs. > > > > > > Assuming this is correct, you should have: > > > > > > Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) > > > Cc: <stable@vger.kernel.org> # v3.12+ > > It's not a bug. Just a redundant disabling of already disabled > interrupts, something which could possibly lead someone to believe that > interrupts could be re-enabled by the power-off handler. I didn't dig any of this out but I'll assume you did :-) So I withdraw my comment ;-) > > > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > > > > index a35f6ebbd2c2..5663ab57cf07 100644 > > > > --- a/arch/arm/kernel/process.c > > > > +++ b/arch/arm/kernel/process.c > > > > @@ -195,7 +195,6 @@ void machine_halt(void) > > > > local_irq_disable(); > > > > smp_send_stop(); > > > > > > > > - local_irq_disable(); > > > > while (1); > > > > } > > > > > > > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > > > > > > > /* Whoops - the platform was unable to reboot. Tell the user! */ > > > > printk("Reboot failed -- System halted\n"); > > > > - local_irq_disable(); > > > > > > ... but wouldn't this reintroduce the the buck which that commit fixed ? > > > > s/buck/bug :-) my fingers have a mind of their own, aparently. > > :) > > No, the interrupts would still be disabled. alright... so far I couldn't find where IRQs are disable before machine_power_off() is called. Starting a do_poweroff(), couldn't find it... Oh well, I'll keep digging. cheers
On Fri, Oct 24, 2014 at 02:42:50PM -0500, Felipe Balbi wrote: > On Fri, Oct 24, 2014 at 09:28:45PM +0200, Johan Hovold wrote: > > On Fri, Oct 24, 2014 at 02:21:11PM -0500, Felipe Balbi wrote: > > > On Fri, Oct 24, 2014 at 02:16:27PM -0500, Felipe Balbi wrote: > > > > On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > > > > > Remove redundant local_irq_disable() at machine halt and restart. > > > > > > > > > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > > > > > smp_send_stop()") interrupts are disabled before stopping secondary > > > > > CPUs. > > > > > > > > Assuming this is correct, you should have: > > > > > > > > Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) > > > > Cc: <stable@vger.kernel.org> # v3.12+ > > > > It's not a bug. Just a redundant disabling of already disabled > > interrupts, something which could possibly lead someone to believe that > > interrupts could be re-enabled by the power-off handler. I meant re-enabled by arm_pm_restart(). > I didn't dig any of this out but I'll assume you did :-) So I withdraw > my comment ;-) > > > > > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > > > > > index a35f6ebbd2c2..5663ab57cf07 100644 > > > > > --- a/arch/arm/kernel/process.c > > > > > +++ b/arch/arm/kernel/process.c > > > > > @@ -195,7 +195,6 @@ void machine_halt(void) > > > > > local_irq_disable(); > > > > > smp_send_stop(); > > > > > > > > > > - local_irq_disable(); > > > > > while (1); > > > > > } > > > > > > > > > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > > > > > > > > > /* Whoops - the platform was unable to reboot. Tell the user! */ > > > > > printk("Reboot failed -- System halted\n"); > > > > > - local_irq_disable(); > > > > > > > > ... but wouldn't this reintroduce the the buck which that commit fixed ? > > > > > > s/buck/bug :-) my fingers have a mind of their own, aparently. > > > > :) > > > > No, the interrupts would still be disabled. > > alright... so far I couldn't find where IRQs are disable before > machine_power_off() is called. Starting a do_poweroff(), couldn't find > it... Oh well, I'll keep digging. It's done a few lines above in the same function. ;) void machine_restart(char *cmd) { local_irq_disable(); ^^^ smp_send_stop(); arm_pm_restart(reboot_mode, cmd); /* Give a grace period for failure to restart of 1s */ mdelay(1000); /* Whoops - the platform was unable to reboot. Tell the user! */ printk("Reboot failed -- System halted\n"); local_irq_disable(); while (1); } [ and similarly in machine_power_off(). ] Johan
On Fri, Oct 24, 2014 at 09:50:29PM +0200, Johan Hovold wrote: > On Fri, Oct 24, 2014 at 02:42:50PM -0500, Felipe Balbi wrote: > > On Fri, Oct 24, 2014 at 09:28:45PM +0200, Johan Hovold wrote: > > > On Fri, Oct 24, 2014 at 02:21:11PM -0500, Felipe Balbi wrote: > > > > On Fri, Oct 24, 2014 at 02:16:27PM -0500, Felipe Balbi wrote: > > > > > On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > > > > > > Remove redundant local_irq_disable() at machine halt and restart. > > > > > > > > > > > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > > > > > > smp_send_stop()") interrupts are disabled before stopping secondary > > > > > > CPUs. > > > > > > > > > > Assuming this is correct, you should have: > > > > > > > > > > Fixes: 44424c3 (ARM: 7803/1: Fix deadlock scenario with smp_send_stop()) > > > > > Cc: <stable@vger.kernel.org> # v3.12+ > > > > > > It's not a bug. Just a redundant disabling of already disabled > > > interrupts, something which could possibly lead someone to believe that > > > interrupts could be re-enabled by the power-off handler. > > I meant re-enabled by arm_pm_restart(). > > > I didn't dig any of this out but I'll assume you did :-) So I withdraw > > my comment ;-) > > > > > > > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > > > > > > index a35f6ebbd2c2..5663ab57cf07 100644 > > > > > > --- a/arch/arm/kernel/process.c > > > > > > +++ b/arch/arm/kernel/process.c > > > > > > @@ -195,7 +195,6 @@ void machine_halt(void) > > > > > > local_irq_disable(); > > > > > > smp_send_stop(); > > > > > > > > > > > > - local_irq_disable(); > > > > > > while (1); > > > > > > } > > > > > > > > > > > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > > > > > > > > > > > /* Whoops - the platform was unable to reboot. Tell the user! */ > > > > > > printk("Reboot failed -- System halted\n"); > > > > > > - local_irq_disable(); > > > > > > > > > > ... but wouldn't this reintroduce the the buck which that commit fixed ? > > > > > > > > s/buck/bug :-) my fingers have a mind of their own, aparently. > > > > > > :) > > > > > > No, the interrupts would still be disabled. > > > > alright... so far I couldn't find where IRQs are disable before > > machine_power_off() is called. Starting a do_poweroff(), couldn't find > > it... Oh well, I'll keep digging. > > It's done a few lines above in the same function. ;) > > void machine_restart(char *cmd) > { > local_irq_disable(); > ^^^ > smp_send_stop(); > > arm_pm_restart(reboot_mode, cmd); > > /* Give a grace period for failure to restart of 1s */ > mdelay(1000); > > /* Whoops - the platform was unable to reboot. Tell the user! */ > printk("Reboot failed -- System halted\n"); > local_irq_disable(); > while (1); > } > > [ and similarly in machine_power_off(). ] oh, now I get it :-) Nevermind, I completely missed that it was duplicated. My bad. Reviewed-by: Felipe Balbi <balbi@ti.com>
On Fri, Oct 24, 2014 at 09:06:32PM +0200, Johan Hovold wrote: > Remove redundant local_irq_disable() at machine halt and restart. > > Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with > smp_send_stop()") interrupts are disabled before stopping secondary > CPUs. > > Signed-off-by: Johan Hovold <johan@kernel.org> Russell, have you had a chance to look at this clean up? Thanks, Johan > --- > arch/arm/kernel/process.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > index a35f6ebbd2c2..5663ab57cf07 100644 > --- a/arch/arm/kernel/process.c > +++ b/arch/arm/kernel/process.c > @@ -195,7 +195,6 @@ void machine_halt(void) > local_irq_disable(); > smp_send_stop(); > > - local_irq_disable(); > while (1); > } > > @@ -237,7 +236,6 @@ void machine_restart(char *cmd) > > /* Whoops - the platform was unable to reboot. Tell the user! */ > printk("Reboot failed -- System halted\n"); > - local_irq_disable(); > while (1); > }
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index a35f6ebbd2c2..5663ab57cf07 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -195,7 +195,6 @@ void machine_halt(void) local_irq_disable(); smp_send_stop(); - local_irq_disable(); while (1); } @@ -237,7 +236,6 @@ void machine_restart(char *cmd) /* Whoops - the platform was unable to reboot. Tell the user! */ printk("Reboot failed -- System halted\n"); - local_irq_disable(); while (1); }
Remove redundant local_irq_disable() at machine halt and restart. Since commit 44424c34049f ("ARM: 7803/1: Fix deadlock scenario with smp_send_stop()") interrupts are disabled before stopping secondary CPUs. Signed-off-by: Johan Hovold <johan@kernel.org> --- arch/arm/kernel/process.c | 2 -- 1 file changed, 2 deletions(-)