On Wed, Dec 13, 2023 at 11:59:45AM -0800, Deepak Gupta wrote: > On Wed, Nov 22, 2023 at 1:45 AM Mark Brown <broonie@xxxxxxxxxx> wrote: > > + if (task->thread.gcs_el0_mode & PR_SHADOW_STACK_ENABLE) > > + gcscre0_el1 |= GCSCRE0_EL1_RVCHKEN | GCSCRE0_EL1_PCRSEL; > If the intent is to disable, is the GCS stack freed or kept around? > I expect if libc is taking the decision to disable, kernel should free it up. > Is it freed in some other flow? Kept around and freed on thread exit. There is a potential race between for example disabling in a signal handler and something trying to walk the stack so we err on the side of caution.
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