@@ -623,6 +623,10 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
{
struct user_fpsimd_state *uregs;
uregs = &target->thread.fpsimd_state.user_fpsimd;
+
+ if (target == current)
+ fpsimd_preserve_current_state();
+
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
}
@@ -898,6 +902,9 @@ static int compat_vfp_get(struct task_struct *target,
uregs = &target->thread.fpsimd_state.user_fpsimd;
+ if (target == current)
+ fpsimd_preserve_current_state();
+
/*
* The VFP registers are packed into the fpsimd_state, so they all sit
* nicely together for us. We just need to create the fpscr separately.
When reading the FPSIMD state of current (which occurs when dumping core), it is possible that userspace has modified the FPSIMD registers since the time the task was last scheduled out. Such changes are not guaranteed to be reflected immedately in thread_struct. As a result, a coredump can contain stale values for these registers. Reading the registers of a stopped task via ptrace is unaffected. This patch explicitly flushes the CPU state back to thread_struct before dumping when operating on current, thus ensuring that coredump contents are up to date. Signed-off-by: Dave Martin <Dave.Martin@arm.com> --- arch/arm64/kernel/ptrace.c | 7 +++++++ 1 file changed, 7 insertions(+)