Messages in this thread | | | From | "Li, Meng" <> | Subject | RE: [PATCH] soc: fsl: dpio: protect smp_processor_id when get processor id | Date | Fri, 15 Oct 2021 16:37:58 +0000 |
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> -----Original Message----- > From: Robin Murphy <robin.murphy@arm.com> > Sent: Friday, October 15, 2021 9:40 PM > To: Li, Meng <Meng.Li@windriver.com>; Roy.Pledge@nxp.com; > leoyang.li@nxp.com; ruxandra.radulescu@nxp.com; horia.geanta@nxp.com > Cc: linux-kernel@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; linux-arm- > kernel@lists.infradead.org > 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, Meng.Li@windriver.com wrote: > > From: Meng Li <meng.li@windriver.com> > > > > 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: stable@vger.kernel.org > > Signed-off-by: Meng Li <Meng.Li@windriver.com> > > --- > > 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]; > >
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