FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-16 22:10:24 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

dma-api: Teach the "DMA-from-stack" check about vmapped stacks

Browse Source 
If we're using CONFIG_VMAP_STACK=y and we manage to point an sg entry
at the stack, then either the sg page will be in highmem or sg_virt()
will return the direct-map alias.  In neither case will the existing
check_for_stack() implementation realize that it's a stack page.

Fix it by explicitly checking for stack pages.

This has no effect by itself.  It's broken out for ease of review.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/448460622731312298bf19dcbacb1606e75de7a9.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2016-08-11 02:35:22 -07:00 committed by Ingo Molnar
parent ba14a194a4
commit b4a0f533e5
1 changed files with 30 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
lib/dma-debug.c
View File

@ -22,6 +22,7 @@
#include <linux/stacktrace.h>
#include <linux/dma-debug.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/export.h>
@ -1164,11 +1165,32 @@ static void check_unmap(struct dma_debug_entry *ref)
put_hash_bucket(bucket, &flags);
}
static void check_for_stack(struct device *dev, void *addr)
static void check_for_stack(struct device *dev,
struct page *page, size_t offset)
{
if (object_is_on_stack(addr))
err_printk(dev, NULL, "DMA-API: device driver maps memory from "
"stack [addr=%p]\n", addr);
void *addr;
struct vm_struct *stack_vm_area = task_stack_vm_area(current);
if (!stack_vm_area) {
/* Stack is direct-mapped. */
if (PageHighMem(page))
return;
addr = page_address(page) + offset;
if (object_is_on_stack(addr))
err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [addr=%p]\n", addr);
} else {
/* Stack is vmalloced. */
int i;
for (i = 0; i < stack_vm_area->nr_pages; i++) {
if (page != stack_vm_area->pages[i])
continue;
addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [probable addr=%p]\n", addr);
break;
}
}
}
static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
@ -1291,10 +1313,11 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
if (map_single)
entry->type = dma_debug_single;
check_for_stack(dev, page, offset);
if (!PageHighMem(page)) {
void *addr = page_address(page) + offset;
check_for_stack(dev, addr);
check_for_illegal_area(dev, addr, size);
}
@ -1386,8 +1409,9 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
entry->sg_call_ents = nents;
entry->sg_mapped_ents = mapped_ents;
check_for_stack(dev, sg_page(s), s->offset);
if (!PageHighMem(sg_page(s))) {
check_for_stack(dev, sg_virt(s));
check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
}