2017-08-09 21:26:06

by Corey Minyard

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

From: Corey Minyard <[email protected]>

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 <[email protected]>
---
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

2017-08-10 07:57:44

by Marcin Nowakowski

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

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, [email protected] wrote:
> From: Corey Minyard <[email protected]>
>
> 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 <[email protected]>
> ---
> 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);
>
>