diff mbox series

[2/7] i2c: core: Use generic_handle_irq_safe() in i2c_handle_smbus_host_notify().

Message ID 20220127113303.3012207-3-bigeasy@linutronix.de (mailing list archive)
State Superseded
Headers show
Series Provide and use generic_handle_irq_safe() where appropriate. | expand

Commit Message

Sebastian Andrzej Siewior Jan. 27, 2022, 11:32 a.m. UTC
The i2c-i801 driver invokes i2c_handle_smbus_host_notify() from his
interrupt service routine. On PREEMPT_RT i2c-i801's handler is forced
threaded with enabled interrupts which leads to a warning by
handle_irq_event_percpu() assuming that irq_default_primary_handler()
enabled interrupts.

i2c-i801's interrupt handler can't be made non-threaded because the
interrupt line is shared with other devices.

Use generic_handle_irq_safe() which can invoked with disabled and enabled
interrupts.

Reported-by: Michael Below <below@judiz.de>
Link: https://bugs.debian.org/1002537
Cc: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/i2c/i2c-core-base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Oleksandr Natalenko Jan. 27, 2022, 2:41 p.m. UTC | #1
Hello.

On čtvrtek 27. ledna 2022 12:32:58 CET Sebastian Andrzej Siewior wrote:
> The i2c-i801 driver invokes i2c_handle_smbus_host_notify() from his
> interrupt service routine. On PREEMPT_RT i2c-i801's handler is forced
> threaded with enabled interrupts which leads to a warning by
> handle_irq_event_percpu() assuming that irq_default_primary_handler()
> enabled interrupts.
> 
> i2c-i801's interrupt handler can't be made non-threaded because the
> interrupt line is shared with other devices.
> 
> Use generic_handle_irq_safe() which can invoked with disabled and enabled
> interrupts.
> 
> Reported-by: Michael Below <below@judiz.de>
> Link: https://bugs.debian.org/1002537
> Cc: Salvatore Bonaccorso <carnil@debian.org>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  drivers/i2c/i2c-core-base.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 2c59dd748a49f..3f9e5303b6163 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -1424,7 +1424,7 @@ int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
>  	if (irq <= 0)
>  		return -ENXIO;
>  
> -	generic_handle_irq(irq);
> +	generic_handle_irq_safe(irq);
>  
>  	return 0;
>  }
> 

Reviewed-by: Oleksandr Natalenko <oleksandr@natalenko.name>

Worth linking [1] [2] and [3] as well maybe?

[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1873673
[2] https://bugzilla.kernel.org/show_bug.cgi?id=202453
[3] https://lore.kernel.org/lkml/20201204201930.vtvitsq6xcftjj3o@spock.localdomain/
Wolfram Sang Jan. 27, 2022, 5:11 p.m. UTC | #2
On Thu, Jan 27, 2022 at 12:32:58PM +0100, Sebastian Andrzej Siewior wrote:
> The i2c-i801 driver invokes i2c_handle_smbus_host_notify() from his
> interrupt service routine. On PREEMPT_RT i2c-i801's handler is forced
> threaded with enabled interrupts which leads to a warning by
> handle_irq_event_percpu() assuming that irq_default_primary_handler()
> enabled interrupts.
> 
> i2c-i801's interrupt handler can't be made non-threaded because the
> interrupt line is shared with other devices.
> 
> Use generic_handle_irq_safe() which can invoked with disabled and enabled
> interrupts.
> 
> Reported-by: Michael Below <below@judiz.de>
> Link: https://bugs.debian.org/1002537
> Cc: Salvatore Bonaccorso <carnil@debian.org>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

I guess you want this to go together with patch 1, so:

Acked-by: Wolfram Sang <wsa@kernel.org>

I agree with adding the kernel bugzilla entry at least:

https://bugzilla.kernel.org/show_bug.cgi?id=202453

Probably the others which Oleksandr metioned, too.
Sebastian Andrzej Siewior Jan. 31, 2022, 11:07 a.m. UTC | #3
On 2022-01-27 18:11:16 [+0100], Wolfram Sang wrote:
> 
> I guess you want this to go together with patch 1, so:
> 
> Acked-by: Wolfram Sang <wsa@kernel.org>
> 
> I agree with adding the kernel bugzilla entry at least:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=202453
> 
> Probably the others which Oleksandr metioned, too.

No, they are not relevant because none of them can be reproduced on a
v5.12+ kernel or any of <v5.12 stable maintained trees.

They triggered in the past only with the `threadirqs' option on the
commandline and this has been fixed by commit
   81e2073c175b8 ("genirq: Disable interrupts for force threaded handlers")

Sebastian
Sebastian Andrzej Siewior Jan. 31, 2022, 11:09 a.m. UTC | #4
On 2022-01-27 15:41:24 [+0100], Oleksandr Natalenko wrote:
> Hello.
Hi,

> Reviewed-by: Oleksandr Natalenko <oleksandr@natalenko.name>
> 
> Worth linking [1] [2] and [3] as well maybe?

no, they are fixed since commit
   81e2073c175b8 ("genirq: Disable interrupts for force threaded handlers")

> [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1873673
> [2] https://bugzilla.kernel.org/show_bug.cgi?id=202453
> [3] https://lore.kernel.org/lkml/20201204201930.vtvitsq6xcftjj3o@spock.localdomain/

Sebastian
diff mbox series

Patch

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 2c59dd748a49f..3f9e5303b6163 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1424,7 +1424,7 @@  int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
 	if (irq <= 0)
 		return -ENXIO;
 
-	generic_handle_irq(irq);
+	generic_handle_irq_safe(irq);
 
 	return 0;
 }