| Message ID | fbaa1409c74ddc7b29b52c87303d2af1db91e2ba.1466974736.git.luto@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Jun 26, 2016 at 02:55:30PM -0700, Andy Lutomirski wrote: > If we're using CONFIG_VMAP_STACK 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. > > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > lib/dma-debug.c | 39 +++++++++++++++++++++++++++++++++------ > 1 file changed, 33 insertions(+), 6 deletions(-) > > diff --git a/lib/dma-debug.c b/lib/dma-debug.c > index 51a76af25c66..5b2e63cba90e 100644 > --- a/lib/dma-debug.c > +++ b/lib/dma-debug.c > @@ -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> > @@ -1162,11 +1163,35 @@ 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); lib/dma-debug.c: In function ‘check_for_stack’: lib/dma-debug.c:1170:36: error: implicit declaration of function ‘task_stack_vm_area’ [-Werror=implicit-function-declaration] struct vm_struct *stack_vm_area = task_stack_vm_area(current); ^ lib/dma-debug.c:1170:36: warning: initialization makes pointer from integer without a cast [-Wint-conversion] cc1: some warnings being treated as errors make[1]: *** [lib/dma-debug.o] Error 1 make: *** [lib] Error 2 make: *** Waiting for unfinished jobs.... Probably reorder pieces from patch 9 to earlier ones...
On Thu, Jun 30, 2016 at 12:37 PM, Borislav Petkov <bp@alien8.de> wrote: > On Sun, Jun 26, 2016 at 02:55:30PM -0700, Andy Lutomirski wrote: >> If we're using CONFIG_VMAP_STACK 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. >> >> Cc: Andrew Morton <akpm@linux-foundation.org> >> Cc: Arnd Bergmann <arnd@arndb.de> >> Signed-off-by: Andy Lutomirski <luto@kernel.org> >> --- >> lib/dma-debug.c | 39 +++++++++++++++++++++++++++++++++------ >> 1 file changed, 33 insertions(+), 6 deletions(-) >> >> diff --git a/lib/dma-debug.c b/lib/dma-debug.c >> index 51a76af25c66..5b2e63cba90e 100644 >> --- a/lib/dma-debug.c >> +++ b/lib/dma-debug.c >> @@ -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> >> @@ -1162,11 +1163,35 @@ 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); > > lib/dma-debug.c: In function ‘check_for_stack’: > lib/dma-debug.c:1170:36: error: implicit declaration of function ‘task_stack_vm_area’ [-Werror=implicit-function-declaration] > struct vm_struct *stack_vm_area = task_stack_vm_area(current); > ^ > lib/dma-debug.c:1170:36: warning: initialization makes pointer from integer without a cast [-Wint-conversion] > cc1: some warnings being treated as errors > make[1]: *** [lib/dma-debug.o] Error 1 > make: *** [lib] Error 2 > make: *** Waiting for unfinished jobs.... > > Probably reorder pieces from patch 9 to earlier ones... I'll address this by reordering it later in the series. The temporary loss of functionality will be unobservable. --Andy
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 51a76af25c66..5b2e63cba90e 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -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> @@ -1162,11 +1163,35 @@ 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) @@ -1289,10 +1314,11 @@ 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); } @@ -1384,8 +1410,9 @@ 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)); }
If we're using CONFIG_VMAP_STACK 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. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andy Lutomirski <luto@kernel.org> --- lib/dma-debug.c | 39 +++++++++++++++++++++++++++++++++------ 1 file changed, 33 insertions(+), 6 deletions(-)