path: root/arch/x86
diff options
authorThomas Gleixner <>2021-06-08 16:36:20 +0200
committerBorislav Petkov <>2021-06-09 10:39:04 +0200
commit12f7764ac61200e32c916f038bdc08f884b0b604 (patch)
treebc45114cf3445c7a9e7c5f795097c8c89bbdeea4 /arch/x86
parentd8778e393afa421f1f117471144f8ce6deb6953a (diff)
x86/process: Check PF_KTHREAD and not current->mm for kernel threads
switch_fpu_finish() checks current->mm as indicator for kernel threads. That's wrong because kernel threads can temporarily use a mm of a user process via kthread_use_mm(). Check the task flags for PF_KTHREAD instead. Fixes: 0cecca9d03c9 ("x86/fpu: Eager switch PKRU state") Signed-off-by: Thomas Gleixner <> Signed-off-by: Borislav Petkov <> Acked-by: Dave Hansen <> Acked-by: Rik van Riel <> Cc: Link:
Diffstat (limited to 'arch/x86')
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index ceeba9f63172..18382ac1ecc4 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -578,7 +578,7 @@ static inline void switch_fpu_finish(struct fpu *new_fpu)
* PKRU state is switched eagerly because it needs to be valid before we
* return to userland e.g. for a copy_to_user() operation.
- if (current->mm) {
+ if (!(current->flags & PF_KTHREAD)) {
pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU);
if (pk)
pkru_val = pk->pkru;