Patch "drivers: base: dma-mapping: page align the size when unmap_kernel_range" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

drivers: base: dma-mapping: page align the size when unmap_kernel_range

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drivers-base-dma-mapping-page-align-the-size-when-unmap_kernel_range.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Peng Fan <[email protected]>
Date: Thu, 21 Jul 2016 16:04:21 +0800
Subject: drivers: base: dma-mapping: page align the size when unmap_kernel_range

From: Peng Fan <[email protected]>

commit 85714108e673cdebf1b96abfd50fb02a29e37577 upstream.

When dma_common_free_remap, the input parameter 'size' may not be page aligned. And, met kernel warning when doing iommu dma for usb on i.MX8 platform:
"

WARNING: CPU: 0 PID: 869 at mm/vmalloc.c:70 vunmap_page_range+0x1cc/0x1d0()
Modules linked in:
CPU: 0 PID: 869 Comm: kworker/u8:2 Not tainted 4.1.12-00444-gc5f9d1d-dirty #147
Hardware name: Freescale i.MX8DV Sabreauto (DT)
Workqueue: ci_otg ci_otg_work
Call trace:
[<ffffffc000089920>] dump_backtrace+0x0/0x124
[<ffffffc000089a54>] show_stack+0x10/0x1c
[<ffffffc0006d1e6c>] dump_stack+0x84/0xc8
[<ffffffc0000b4568>] warn_slowpath_common+0x98/0xd0
[<ffffffc0000b4664>] warn_slowpath_null+0x14/0x20
[<ffffffc000170348>] vunmap_page_range+0x1c8/0x1d0
[<ffffffc000170388>] unmap_kernel_range+0x20/0x88
[<ffffffc000460ad0>] dma_common_free_remap+0x74/0x84
[<ffffffc0000940d8>] __iommu_free_attrs+0x9c/0x178
[<ffffffc0005032bc>] ehci_mem_cleanup+0x140/0x194
[<ffffffc000503548>] ehci_stop+0x8c/0xdc
[<ffffffc0004e8258>] usb_remove_hcd+0xf0/0x1cc
[<ffffffc000516bc0>] host_stop+0x1c/0x58
[<ffffffc000514240>] ci_otg_work+0xdc/0x120
[<ffffffc0000c9c34>] process_one_work+0x134/0x33c
[<ffffffc0000c9f78>] worker_thread+0x13c/0x47c
[<ffffffc0000cf43c>] kthread+0xd8/0xf0

"

For dma_common_pages_remap:
dma_common_pages_remap
|->get_vm_area_caller

        |->__get_vm_area_node
            |->size = PAGE_ALIGN(size);   Round up to page aligned

So, in dma_common_free_remap, we also need a page aligned size, pass 'PAGE_ALIGN(size)' to unmap_kernel_range.

---
 drivers/base/dma-mapping.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -335,7 +335,7 @@ void dma_common_free_remap(void *cpu_add
 		return;
 	}
 
-	unmap_kernel_range((unsigned long)cpu_addr, size);
+	unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
 	vunmap(cpu_addr);
 }
 #endif

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drivers-base-dma-mapping-page-align-the-size-when-unmap_kernel_range.patch