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Message-Id: <1437008972-9140-165-git-send-email-kamal@canonical.com>
Date: Wed, 15 Jul 2015 18:08:05 -0700
From: Kamal Mostafa <kamal@...onical.com>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
kernel-team@...ts.ubuntu.com
Cc: Pali Rohár <pali.rohar@...il.com>,
Darren Hart <dvhart@...ux.intel.com>,
Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.19.y-ckt 164/251] dell-laptop: Fix allocating & freeing SMI buffer page
3.19.8-ckt4 -stable review patch. If anyone has any objections, please let me know.
------------------
From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali.rohar@...il.com>
commit b8830a4e71b15d0364ac8e6c55301eea73f211da upstream.
This commit fix kernel crash when probing for rfkill devices in dell-laptop
driver failed. Function free_page() was incorrectly used on struct page *
instead of virtual address of SMI buffer.
This commit also simplify allocating page for SMI buffer by using
__get_free_page() function instead of sequential call of functions
alloc_page() and page_address().
Signed-off-by: Pali Rohár <pali.rohar@...il.com>
Acked-by: Michal Hocko <mhocko@...e.cz>
Signed-off-by: Darren Hart <dvhart@...ux.intel.com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
drivers/platform/x86/dell-laptop.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index 3d21efe..7da7e4c 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -271,7 +271,6 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
};
static struct calling_interface_buffer *buffer;
-static struct page *bufferpage;
static DEFINE_MUTEX(buffer_mutex);
static int hwswitch_state;
@@ -824,12 +823,11 @@ static int __init dell_init(void)
* Allocate buffer below 4GB for SMI data--only 32-bit physical addr
* is passed to SMI handler.
*/
- bufferpage = alloc_page(GFP_KERNEL | GFP_DMA32);
- if (!bufferpage) {
+ buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
+ if (!buffer) {
ret = -ENOMEM;
goto fail_buffer;
}
- buffer = page_address(bufferpage);
ret = dell_setup_rfkill();
@@ -891,7 +889,7 @@ fail_backlight:
cancel_delayed_work_sync(&dell_rfkill_work);
dell_cleanup_rfkill();
fail_rfkill:
- free_page((unsigned long)bufferpage);
+ free_page((unsigned long)buffer);
fail_buffer:
platform_device_del(platform_device);
fail_platform_device2:
--
1.9.1
--
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