Given a large enough memory allocation, it is possible to wrap the
pinned_vm counter. Check for addition overflow to prevent such
eventualities.
Fixes: 40ddacf2dda9 ("RDMA/umem: Don't hold mmap_sem for too long")
Reported-by: Jason Gunthorpe <jgg@xxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
---
drivers/infiniband/core/umem.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index e54e50dd854b..0b082807e695 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -85,6 +85,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
struct page **page_list;
struct vm_area_struct **vma_list;
unsigned long lock_limit;
+ unsigned long new_pinned;
unsigned long cur_base;
struct mm_struct *mm;
unsigned long npages;
@@ -155,12 +156,13 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
down_write(&mm->mmap_sem);
- mm->pinned_vm += npages;
- if ((mm->pinned_vm > lock_limit) && !capable(CAP_IPC_LOCK)) {
+ if (check_add_overflow(mm->pinned_vm, npages, &new_pinned) ||
+ (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) {
up_write(&mm->mmap_sem);
ret = -ENOMEM;
- goto vma;
+ goto out;
}
+ mm->pinned_vm = new_pinned;
up_write(&mm->mmap_sem);
cur_base = addr & PAGE_MASK;
--
2.17.1
