diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-04-03 13:37:28 +0300 |
|---|---|---|
| committer | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-04-12 17:29:18 +0300 |
| commit | 8d07c0e4ba660724f51de93fe762c2ee05349289 (patch) | |
| tree | 9932a561f2e315bd81dd4080f88a0215265cd611 | |
| parent | 9f054d94b792addb808fbcee67c2cf2a98580390 (diff) | |
| download | linux-lam.tar.gz | |
x86/mm/iommu/sva: Do not allow to set FORCE_TAGGED_SVA bit from outsidelam
arch_prctl(ARCH_FORCE_TAGGED_SVA) overrides the default and allows LAM
and SVA to co-exist in the process. It is expected by called by the
process when it knows what it is doing.
arch_prctl() operates on the current process, but the same code is
reachable from ptrace where it can be called on arbitrary task.
Make it strict and only allow to set MM_CONTEXT_FORCE_TAGGED_SVA for the
current process.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 23e5d9ec2bab ("x86/mm/iommu/sva: Make LAM and SVA mutually exclusive")
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
| -rw-r--r-- | arch/x86/kernel/process_64.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 4cc7376b878601..018d47b31cc1be 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -883,6 +883,8 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) case ARCH_ENABLE_TAGGED_ADDR: return prctl_enable_tagged_addr(task->mm, arg2); case ARCH_FORCE_TAGGED_SVA: + if (current != task) + return -EINVAL; set_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &task->mm->context.flags); return 0; case ARCH_GET_MAX_TAG_BITS: |