linux-kernel - [PATCH 3.18 25/54] drm/ast: Fix incorrect free on ioregs

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Date:   Tue, 11 Dec 2018 16:41:13 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sam Bobroff <sbobroff@...ux.ibm.com>,
        Dave Airlie <airlied@...hat.com>
Subject: [PATCH 3.18 25/54] drm/ast: Fix incorrect free on ioregs

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sam Bobroff <sbobroff@...ux.ibm.com>

commit dc25ab067645eabd037f1a23d49a666f9e0b8c68 upstream.

If the platform has no IO space, ioregs is placed next to the already
allocated regs. In this case, it should not be separately freed.

This prevents a kernel warning from __vunmap "Trying to vfree()
nonexistent vm area" when unloading the driver.

Fixes: 0dd68309b9c5 ("drm/ast: Try to use MMIO registers when PIO isn't supported")

Signed-off-by: Sam Bobroff <sbobroff@...ux.ibm.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/ast/ast_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -489,7 +489,8 @@ int ast_driver_unload(struct drm_device
 	drm_mode_config_cleanup(dev);
 
 	ast_mm_fini(ast);
-	pci_iounmap(dev->pdev, ast->ioregs);
+	if (ast->ioregs != ast->regs + AST_IO_MM_OFFSET)
+		pci_iounmap(dev->pdev, ast->ioregs);
 	pci_iounmap(dev->pdev, ast->regs);
 	kfree(ast);
 	return 0;