drivers/edac/ move a kfree() to after last use

drivers/edac/ move a kfree() to after last use

[Darren Jenkins]

Move a kfree() below the last use of the memory

Coverity CID: 13142

Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index df5b684..15b8b3c 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -2925,10 +2925,10 @@ static void __devexit
amd64_remove_one_instance(struct pci_dev *pdev)
 
 	amd64_free_mc_sibling_devices(pvt);
 
-	kfree(pvt);
 	mci->pvt_info = NULL;
 
 	mci_lookup[pvt->mc_node_id] = NULL;
+	kfree(pvt);
 
 	/* unregister from EDAC MCE */
 	amd_report_gart_errors(false);

Re: drivers/edac/ move a kfree() to after last use

[Borislav Petkov]

On Mon, Dec 21, 2009 at 03:38:26PM +1100, Darren Jenkins wrote:
> 
> Move a kfree() below the last use of the memory
> 
> Coverity CID: 13142
> 
> Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>

Thanks for catching that. Here's a better version that does all the
freeing at the end of the function.

--
From: Borislav Petkov <borislav.petkov@amd.com>
Date: Mon, 21 Dec 2009 15:15:59 +0100
Subject: [PATCH] amd64_edac: fix driver instance freeing

Fix use-after-free errors by pushing all memory-freeing calls to the end
of amd64_remove_one_instance().

Reported-by: Darren Jenkins <darrenrjenkins@gmail.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 drivers/edac/amd64_edac.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 784cc5a..fb0d36b 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -2929,16 +2929,15 @@ static void __devexit amd64_remove_one_instance(struct pci_dev *pdev)
 
 	amd64_free_mc_sibling_devices(pvt);
 
-	kfree(pvt);
-	mci->pvt_info = NULL;
-
-	mci_lookup[pvt->mc_node_id] = NULL;
-
 	/* unregister from EDAC MCE */
 	amd_report_gart_errors(false);
 	amd_unregister_ecc_decoder(amd64_decode_bus_error);
 
 	/* Free the EDAC CORE resources */
+	mci->pvt_info = NULL;
+	mci_lookup[pvt->mc_node_id] = NULL;
+
+	kfree(pvt);
 	edac_mc_free(mci);
 }
 
-- 
1.6.5.4


-- 
Regards/Gruss,
Boris.

Operating | Advanced Micro Devices GmbH
  System  | Karl-Hammerschmidt-Str. 34, 85609 Dornach b. München, Germany
 Research | Geschäftsführer: Andrew Bowd, Thomas M. McCoy, Giuliano Meroni
  Center  | Sitz: Dornach, Gemeinde Aschheim, Landkreis München
  (OSRC)  | Registergericht München, HRB Nr. 43632