From: Meng Li <[email protected]>
When enable debug kernel configs,there will be calltrace as below:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x20/0x30
CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.10.63-yocto-standard #1
Hardware name: NXP Layerscape LX2160ARDB (DT)
Call trace:
dump_backtrace+0x0/0x1a0
show_stack+0x24/0x30
dump_stack+0xf0/0x13c
check_preemption_disabled+0x100/0x110
debug_smp_processor_id+0x20/0x30
dpaa2_io_query_fq_count+0xdc/0x154
dpaa2_eth_stop+0x144/0x314
__dev_close_many+0xdc/0x160
__dev_change_flags+0xe8/0x220
dev_change_flags+0x30/0x70
ic_close_devs+0x50/0x78
ip_auto_config+0xed0/0xf10
do_one_initcall+0xac/0x460
kernel_init_freeable+0x30c/0x378
kernel_init+0x20/0x128
ret_from_fork+0x10/0x38
Because smp_processor_id() should be invoked in preempt disable status.
So, add preempt_disable/enable() to protect smp_processor_id().
Fixes: c89105c9b390 ("staging: fsl-mc: Move DPIO from staging to drivers/soc/fsl")
Cc: [email protected]
Signed-off-by: Meng Li <[email protected]>
---
drivers/soc/fsl/dpio/dpio-service.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/soc/fsl/dpio/dpio-service.c b/drivers/soc/fsl/dpio/dpio-service.c
index 19f47ea9dab0..afc3b89b0fc5 100644
--- a/drivers/soc/fsl/dpio/dpio-service.c
+++ b/drivers/soc/fsl/dpio/dpio-service.c
@@ -58,8 +58,11 @@ static inline struct dpaa2_io *service_select_by_cpu(struct dpaa2_io *d,
* If cpu == -1, choose the current cpu, with no guarantees about
* potentially being migrated away.
*/
- if (cpu < 0)
- cpu = smp_processor_id();
+ if (cpu < 0) {
+ preempt_disable();
+ cpu = smp_processor_id();
+ preempt_enable();
+ }
/* If a specific cpu was requested, pick it up immediately */
return dpio_by_cpu[cpu];
--
2.17.1
On 2021-10-15 07:36, [email protected] wrote:
> From: Meng Li <[email protected]>
>
> When enable debug kernel configs,there will be calltrace as below:
>
> BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
> caller is debug_smp_processor_id+0x20/0x30
> CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.10.63-yocto-standard #1
> Hardware name: NXP Layerscape LX2160ARDB (DT)
> Call trace:
> dump_backtrace+0x0/0x1a0
> show_stack+0x24/0x30
> dump_stack+0xf0/0x13c
> check_preemption_disabled+0x100/0x110
> debug_smp_processor_id+0x20/0x30
> dpaa2_io_query_fq_count+0xdc/0x154
> dpaa2_eth_stop+0x144/0x314
> __dev_close_many+0xdc/0x160
> __dev_change_flags+0xe8/0x220
> dev_change_flags+0x30/0x70
> ic_close_devs+0x50/0x78
> ip_auto_config+0xed0/0xf10
> do_one_initcall+0xac/0x460
> kernel_init_freeable+0x30c/0x378
> kernel_init+0x20/0x128
> ret_from_fork+0x10/0x38
>
> Because smp_processor_id() should be invoked in preempt disable status.
> So, add preempt_disable/enable() to protect smp_processor_id().
If preemption doesn't matter anyway, as the comment in the context
implies, then it probably makes more sense just to use
raw_smp_processor_id() instead.
Robin.
> Fixes: c89105c9b390 ("staging: fsl-mc: Move DPIO from staging to drivers/soc/fsl")
> Cc: [email protected]
> Signed-off-by: Meng Li <[email protected]>
> ---
> drivers/soc/fsl/dpio/dpio-service.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/fsl/dpio/dpio-service.c b/drivers/soc/fsl/dpio/dpio-service.c
> index 19f47ea9dab0..afc3b89b0fc5 100644
> --- a/drivers/soc/fsl/dpio/dpio-service.c
> +++ b/drivers/soc/fsl/dpio/dpio-service.c
> @@ -58,8 +58,11 @@ static inline struct dpaa2_io *service_select_by_cpu(struct dpaa2_io *d,
> * If cpu == -1, choose the current cpu, with no guarantees about
> * potentially being migrated away.
> */
> - if (cpu < 0)
> - cpu = smp_processor_id();
> + if (cpu < 0) {
> + preempt_disable();
> + cpu = smp_processor_id();
> + preempt_enable();
> + }
>
> /* If a specific cpu was requested, pick it up immediately */
> return dpio_by_cpu[cpu];
>
> -----Original Message-----
> From: Robin Murphy <[email protected]>
> Sent: Friday, October 15, 2021 9:40 PM
> To: Li, Meng <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected]
> Cc: [email protected]; [email protected]; linux-arm-
> [email protected]
> Subject: Re: [PATCH] soc: fsl: dpio: protect smp_processor_id when get
> processor id
>
> [Please note: This e-mail is from an EXTERNAL e-mail address]
>
> On 2021-10-15 07:36, [email protected] wrote:
> > From: Meng Li <[email protected]>
> >
> > When enable debug kernel configs,there will be calltrace as below:
> >
> > BUG: using smp_processor_id() in preemptible [00000000] code:
> > swapper/0/1 caller is debug_smp_processor_id+0x20/0x30
> > CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.10.63-yocto-standard #1
> > Hardware name: NXP Layerscape LX2160ARDB (DT) Call trace:
> > dump_backtrace+0x0/0x1a0
> > show_stack+0x24/0x30
> > dump_stack+0xf0/0x13c
> > check_preemption_disabled+0x100/0x110
> > debug_smp_processor_id+0x20/0x30
> > dpaa2_io_query_fq_count+0xdc/0x154
> > dpaa2_eth_stop+0x144/0x314
> > __dev_close_many+0xdc/0x160
> > __dev_change_flags+0xe8/0x220
> > dev_change_flags+0x30/0x70
> > ic_close_devs+0x50/0x78
> > ip_auto_config+0xed0/0xf10
> > do_one_initcall+0xac/0x460
> > kernel_init_freeable+0x30c/0x378
> > kernel_init+0x20/0x128
> > ret_from_fork+0x10/0x38
> >
> > Because smp_processor_id() should be invoked in preempt disable status.
> > So, add preempt_disable/enable() to protect smp_processor_id().
>
> If preemption doesn't matter anyway, as the comment in the context implies,
> then it probably makes more sense just to use
> raw_smp_processor_id() instead.
>
Thanks for your professional suggest, I will raw_smp_processor_id() and test.
If works fine, I will send v2 patch.
Thanks,
Limeng
> Robin.
>
> > Fixes: c89105c9b390 ("staging: fsl-mc: Move DPIO from staging to
> > drivers/soc/fsl")
> > Cc: [email protected]
> > Signed-off-by: Meng Li <[email protected]>
> > ---
> > drivers/soc/fsl/dpio/dpio-service.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/soc/fsl/dpio/dpio-service.c
> > b/drivers/soc/fsl/dpio/dpio-service.c
> > index 19f47ea9dab0..afc3b89b0fc5 100644
> > --- a/drivers/soc/fsl/dpio/dpio-service.c
> > +++ b/drivers/soc/fsl/dpio/dpio-service.c
> > @@ -58,8 +58,11 @@ static inline struct dpaa2_io
> *service_select_by_cpu(struct dpaa2_io *d,
> > * If cpu == -1, choose the current cpu, with no guarantees about
> > * potentially being migrated away.
> > */
> > - if (cpu < 0)
> > - cpu = smp_processor_id();
> > + if (cpu < 0) {
> > + preempt_disable();
> > + cpu = smp_processor_id();
> > + preempt_enable();
> > + }
> >
> > /* If a specific cpu was requested, pick it up immediately */
> > return dpio_by_cpu[cpu];
> >