Message ID | 20231027055622.21544-1-jay.buddhabhatti@amd.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | soc: xilinx: Fix for call trace due to the usage of smp_processor_id() | expand |
On 10/27/23 07:56, Jay Buddhabhatti wrote: > From: HariBabu Gattem <haribabu.gattem@xilinx.com> > > When preemption is enabled in kernel and if any task which can be > preempted should not use smp_processor_id() directly, since CPU > switch can happen at any time, the previous value of cpu_id > differs with current cpu_id. As a result we see the below call trace > during xlnx_event_manager_probe. > > [ 6.140197] dump_backtrace+0x0/0x190 > [ 6.143884] show_stack+0x18/0x40 > [ 6.147220] dump_stack_lvl+0x7c/0xa0 > [ 6.150907] dump_stack+0x18/0x34 > [ 6.154241] check_preemption_disabled+0x124/0x134 > [ 6.159068] debug_smp_processor_id+0x20/0x2c > [ 6.163453] xlnx_event_manager_probe+0x48/0x250 > > To protect cpu_id, It is recommended to use get_cpu()/put_cpu() > to disable preemption, get the cpu_id and enable preemption respectively. > (For Reference, Documentation/locking/preempt-locking.rst and > Documentation/kernel-hacking/hacking.rst) > > Use preempt_disable()/smp_processor_id()/preempt_enable() > API's to achieve the same. > > Signed-off-by: HariBabu Gattem <haribabu.gattem@xilinx.com> > Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com> > --- > drivers/soc/xilinx/xlnx_event_manager.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/soc/xilinx/xlnx_event_manager.c b/drivers/soc/xilinx/xlnx_event_manager.c > index 86a048a10a13..edfb1d5c10c6 100644 > --- a/drivers/soc/xilinx/xlnx_event_manager.c > +++ b/drivers/soc/xilinx/xlnx_event_manager.c > @@ -555,7 +555,7 @@ static void xlnx_disable_percpu_irq(void *data) > static int xlnx_event_init_sgi(struct platform_device *pdev) > { > int ret = 0; > - int cpu = smp_processor_id(); > + int cpu; > /* > * IRQ related structures are used for the following: > * for each SGI interrupt ensure its mapped by GIC IRQ domain > @@ -592,9 +592,12 @@ static int xlnx_event_init_sgi(struct platform_device *pdev) > sgi_fwspec.param[0] = sgi_num; > virq_sgi = irq_create_fwspec_mapping(&sgi_fwspec); > > + cpu = get_cpu(); > per_cpu(cpu_number1, cpu) = cpu; > ret = request_percpu_irq(virq_sgi, xlnx_event_handler, "xlnx_event_mgmt", > &cpu_number1); > + put_cpu(); > + > WARN_ON(ret); > if (ret) { > irq_dispose_mapping(virq_sgi); Applied. M
diff --git a/drivers/soc/xilinx/xlnx_event_manager.c b/drivers/soc/xilinx/xlnx_event_manager.c index 86a048a10a13..edfb1d5c10c6 100644 --- a/drivers/soc/xilinx/xlnx_event_manager.c +++ b/drivers/soc/xilinx/xlnx_event_manager.c @@ -555,7 +555,7 @@ static void xlnx_disable_percpu_irq(void *data) static int xlnx_event_init_sgi(struct platform_device *pdev) { int ret = 0; - int cpu = smp_processor_id(); + int cpu; /* * IRQ related structures are used for the following: * for each SGI interrupt ensure its mapped by GIC IRQ domain @@ -592,9 +592,12 @@ static int xlnx_event_init_sgi(struct platform_device *pdev) sgi_fwspec.param[0] = sgi_num; virq_sgi = irq_create_fwspec_mapping(&sgi_fwspec); + cpu = get_cpu(); per_cpu(cpu_number1, cpu) = cpu; ret = request_percpu_irq(virq_sgi, xlnx_event_handler, "xlnx_event_mgmt", &cpu_number1); + put_cpu(); + WARN_ON(ret); if (ret) { irq_dispose_mapping(virq_sgi);