diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/dma-debug.c | 36 | ||||
| -rw-r--r-- | lib/syscall.c | 15 |
2 files changed, 43 insertions, 8 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index fcfa1939ac41..06f02f6aecd2 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> @@ -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)); } diff --git a/lib/syscall.c b/lib/syscall.c index e30e03932480..63239e097b13 100644 --- a/lib/syscall.c +++ b/lib/syscall.c @@ -7,9 +7,19 @@ static int collect_syscall(struct task_struct *target, long *callno, unsigned long args[6], unsigned int maxargs, unsigned long *sp, unsigned long *pc) { - struct pt_regs *regs = task_pt_regs(target); - if (unlikely(!regs)) + struct pt_regs *regs; + + if (!try_get_task_stack(target)) { + /* Task has no stack, so the task isn't in a syscall. */ + *callno = -1; + return 0; + } + + regs = task_pt_regs(target); + if (unlikely(!regs)) { + put_task_stack(target); return -EAGAIN; + } *sp = user_stack_pointer(regs); *pc = instruction_pointer(regs); @@ -18,6 +28,7 @@ static int collect_syscall(struct task_struct *target, long *callno, if (*callno != -1L && maxargs > 0) syscall_get_arguments(target, regs, 0, maxargs, args); + put_task_stack(target); return 0; } |