[PATCH] mips: Fix using smp_processor_id() when preemptible

[PATCH] mips: Fix using smp_processor_id() when preemptible

[minyard]

From: Corey Minyard <cminyard@mvista.com>

I was getting the following:

BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is pcibios_set_cache_line_size+0x10/0x58

pcibios_set_cache_line_size() used current_cpu_data outside of
an unpreemptible context.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 arch/mips/pci/pci.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index bd67ac7..afd2f8a 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -28,9 +28,11 @@ EXPORT_SYMBOL(PCIBIOS_MIN_MEM);
 
 static int __init pcibios_set_cache_line_size(void)
 {
-	struct cpuinfo_mips *c = &current_cpu_data;
+	struct cpuinfo_mips *c;
 	unsigned int lsize;
 
+	preempt_disable();
+	c = &current_cpu_data;
 	/*
 	 * Set PCI cacheline size to that of the highest level in the
 	 * cache hierarchy.
@@ -38,6 +40,7 @@ static int __init pcibios_set_cache_line_size(void)
 	lsize = c->dcache.linesz;
 	lsize = c->scache.linesz ? : lsize;
 	lsize = c->tcache.linesz ? : lsize;
+	preempt_enable();
 
 	BUG_ON(!lsize);
 
-- 
2.7.4

Re: [PATCH] mips: Fix using smp_processor_id() when preemptible

[Marcin Nowakowski]

Hi Corey,

This has already been fixed here:
https://git.linux-mips.org/cgit/ralf/upstream-sfr.git/commit/?id=21da5332327b6d183bd93336ecf29c70bc609b7b

https://git.linux-mips.org/cgit/ralf/upstream-sfr.git/commit/?id=735302665c353d6756e7fa2a2cf41b039299f732

Marcin

On 09.08.2017 23:25, minyard@acm.org wrote:
> From: Corey Minyard <cminyard@mvista.com>
> 
> I was getting the following:
> 
> BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
> caller is pcibios_set_cache_line_size+0x10/0x58
> 
> pcibios_set_cache_line_size() used current_cpu_data outside of
> an unpreemptible context.
> 
> Signed-off-by: Corey Minyard <cminyard@mvista.com>
> ---
>   arch/mips/pci/pci.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
> index bd67ac7..afd2f8a 100644
> --- a/arch/mips/pci/pci.c
> +++ b/arch/mips/pci/pci.c
> @@ -28,9 +28,11 @@ EXPORT_SYMBOL(PCIBIOS_MIN_MEM);
>   
>   static int __init pcibios_set_cache_line_size(void)
>   {
> -	struct cpuinfo_mips *c = &current_cpu_data;
> +	struct cpuinfo_mips *c;
>   	unsigned int lsize;
>   
> +	preempt_disable();
> +	c = &current_cpu_data;
>   	/*
>   	 * Set PCI cacheline size to that of the highest level in the
>   	 * cache hierarchy.
> @@ -38,6 +40,7 @@ static int __init pcibios_set_cache_line_size(void)
>   	lsize = c->dcache.linesz;
>   	lsize = c->scache.linesz ? : lsize;
>   	lsize = c->tcache.linesz ? : lsize;
> +	preempt_enable();
>   
>   	BUG_ON(!lsize);
>   
>