| Message ID | 1506085728-10754-1-git-send-email-clombard@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | cxl: Fix memory page not handled | expand |
Le 22/09/2017 à 15:08, Christophe Lombard a écrit : > The a in-kernel 'library' API can be called by drivers to help "the in-kernel library" > interaction with an IBM XSL on a POWER9 system. > > The cxllib_handle_fault() API is used to handle memory fault. All memory > pages of the specified buffer have to be handled but the last page is > never touched, and the address the adapter is trying to access is never nitpick: "never touched"? I thought it could be. It all depends on the input parameter. But it doesn't really matter, there's a bug. > sent to the kernel for resolution. > > This patch updates the loop on the memory pages to be handled. > > Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> > > Fixes: 3ced8d730063 ("cxl: Export library to support IBM XSL"); > --- > drivers/misc/cxl/cxllib.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c > index 5dba23c..0c1eaf0 100644 > --- a/drivers/misc/cxl/cxllib.c > +++ b/drivers/misc/cxl/cxllib.c > @@ -219,8 +219,17 @@ int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags) > > down_read(&mm->mmap_sem); > > - for (dar = addr; dar < addr + size; dar += page_size) { > - if (!vma || dar < vma->vm_start || dar > vma->vm_end) { > + vma = find_vma(mm, addr); > + if (!vma) { > + pr_err("Can't find vma for addr %016llx\n", addr); > + rc = -EFAULT; > + goto out; > + } > + /* get the size of the pages allocated */ > + page_size = vma_kernel_pagesize(vma); > + > + for (dar = (addr & ~(page_size - 1)); dar <= (addr + size); dar += page_size) { The end boundary should be 'dar < (addr + size)', or we may hit an extra page, which could fail (and cause the call to return an error). Thanks to John for spotting it! Fred > + if (dar < vma->vm_start || dar > vma->vm_end) { > vma = find_vma(mm, addr); > if (!vma) { > pr_err("Can't find vma for addr %016llx\n", addr); >
diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c index 5dba23c..0c1eaf0 100644 --- a/drivers/misc/cxl/cxllib.c +++ b/drivers/misc/cxl/cxllib.c @@ -219,8 +219,17 @@ int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags) down_read(&mm->mmap_sem); - for (dar = addr; dar < addr + size; dar += page_size) { - if (!vma || dar < vma->vm_start || dar > vma->vm_end) { + vma = find_vma(mm, addr); + if (!vma) { + pr_err("Can't find vma for addr %016llx\n", addr); + rc = -EFAULT; + goto out; + } + /* get the size of the pages allocated */ + page_size = vma_kernel_pagesize(vma); + + for (dar = (addr & ~(page_size - 1)); dar <= (addr + size); dar += page_size) { + if (dar < vma->vm_start || dar > vma->vm_end) { vma = find_vma(mm, addr); if (!vma) { pr_err("Can't find vma for addr %016llx\n", addr);
The a in-kernel 'library' API can be called by drivers to help interaction with an IBM XSL on a POWER9 system. The cxllib_handle_fault() API is used to handle memory fault. All memory pages of the specified buffer have to be handled but the last page is never touched, and the address the adapter is trying to access is never sent to the kernel for resolution. This patch updates the loop on the memory pages to be handled. Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Fixes: 3ced8d730063 ("cxl: Export library to support IBM XSL"); --- drivers/misc/cxl/cxllib.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)