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| author | Thomas Gleixner <tglx@linutronix.de> | 2021-06-08 16:36:20 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-06-09 10:39:04 +0200 |
| commit | 12f7764ac61200e32c916f038bdc08f884b0b604 (patch) | |
| tree | bc45114cf3445c7a9e7c5f795097c8c89bbdeea4 | |
| parent | x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer (diff) | |
| download | linux-12f7764ac61200e32c916f038bdc08f884b0b604.tar.xz linux-12f7764ac61200e32c916f038bdc08f884b0b604.zip | |
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 <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210608144345.912645927@linutronix.de
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 2 |
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; |