| From foo@baz Sun May 27 17:33:38 CEST 2018 |
| From: Davidlohr Bueso <dave@stgolabs.net> |
| Date: Mon, 22 Jan 2018 09:21:37 -0800 |
| Subject: ia64/err-inject: Use get_user_pages_fast() |
| |
| From: Davidlohr Bueso <dave@stgolabs.net> |
| |
| [ Upstream commit 69c907022a7d9325cdc5c9dd064571e445df9a47 ] |
| |
| At the point of sysfs callback, the call to gup is |
| done without mmap_sem (or any lock for that matter). |
| This is racy. As such, use the get_user_pages_fast() |
| alternative and safely avoid taking the lock, if possible. |
| |
| Signed-off-by: Davidlohr Bueso <dbueso@suse.de> |
| Signed-off-by: Tony Luck <tony.luck@intel.com> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/ia64/kernel/err_inject.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/arch/ia64/kernel/err_inject.c |
| +++ b/arch/ia64/kernel/err_inject.c |
| @@ -142,7 +142,7 @@ store_virtual_to_phys(struct device *dev |
| u64 virt_addr=simple_strtoull(buf, NULL, 16); |
| int ret; |
| |
| - ret = get_user_pages(virt_addr, 1, FOLL_WRITE, NULL, NULL); |
| + ret = get_user_pages_fast(virt_addr, 1, FOLL_WRITE, NULL); |
| if (ret<=0) { |
| #ifdef ERR_INJ_DEBUG |
| printk("Virtual address %lx is not existing.\n",virt_addr); |
