[PATCH 0/2] Fix double mem region release

[PATCH 0/2] Fix double mem region release

[Ladislav Michl]

Two one-liners for the same issue, second bug occurrence is just
a copy&pasted mistake from 2011...

Ladislav Michl (2):
  devres: Fix double mem region release in devm_ioremap_resource()
  PCI: Fix double mem region release in devm_pci_remap_cfg_resource()

 drivers/pci/pci.c | 1 -
 lib/devres.c      | 1 -
 2 files changed, 2 deletions(-)

-- 
2.15.1

[PATCH 1/2] devres: Fix double mem region release in devm_ioremap_resource()

[Ladislav Michl]

devm_release_mem_region() is called explicitely in case
devm_ioremap() fails, however the same release function
is later called also as devres release of
devm_request_mem_region() causing double resource free.

Fixes: 72f8c0bfa0de ("lib: devres: add convenience function to remap a resource")
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
---
 lib/devres.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/devres.c b/lib/devres.c
index 5f2aedd58bc5..584356a568d0 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -156,7 +156,6 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
 	dest_ptr = devm_ioremap(dev, res->start, size);
 	if (!dest_ptr) {
 		dev_err(dev, "ioremap failed for resource %pR\n", res);
-		devm_release_mem_region(dev, res->start, size);
 		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
 	}
 
-- 
2.15.1

[PATCH 2/2] PCI: Fix double mem region release in devm_pci_remap_cfg_resource()

[Ladislav Michl]

devm_release_mem_region() is called explicitely in case
devm_pci_remap_cfgspace() fails, however the same release
function is later called also as devres release of
devm_request_mem_region() causing double resource free.

Fixes: 490cb6ddb17d ("PCI: Implement devm_pci_remap_cfgspace()")
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
---
 drivers/pci/pci.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 764ca7b8840d..8f9d81a23ca5 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3607,7 +3607,6 @@ void __iomem *devm_pci_remap_cfg_resource(struct device *dev,
 	dest_ptr = devm_pci_remap_cfgspace(dev, res->start, size);
 	if (!dest_ptr) {
 		dev_err(dev, "ioremap failed for resource %pR\n", res);
-		devm_release_mem_region(dev, res->start, size);
 		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
 	}
 
-- 
2.15.1

Re: [PATCH 0/2] Fix double mem region release

[Ladislav Michl]

On Fri, Jan 19, 2018 at 07:03:10PM +0100, Ladislav Michl wrote:
> Two one-liners for the same issue, second bug occurrence is just
> a copy&pasted mistake from 2011...
> 
> Ladislav Michl (2):
>   devres: Fix double mem region release in devm_ioremap_resource()
>   PCI: Fix double mem region release in devm_pci_remap_cfg_resource()

Hmm, that is really shame :-/ My test setup triggered "Trying to free
nonexistent resource" warning, but dissasembly of lib/devres.o shows
no call to devres_destroy, which seems that WARN_ON in
__devm_release_region() is optimized out. Strange. So far sorry
for the noise, I'll try figure out what broke after weekend.

>  drivers/pci/pci.c | 1 -
>  lib/devres.c      | 1 -
>  2 files changed, 2 deletions(-)
> 
> -- 
> 2.15.1
>