Commit "x86/mm/pat: Disable preemption around __flush_tlb_all()" added a warning if __flush_tlb_all() is invoked in preemptible context. On !RT the warning does not trigger because a spin lock is acquired which disables preemption. On RT the spin lock does not disable preemption and so the warning is seen.
Disable preemption to avoid the warning in __flush_tlb_all(). Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- arch/x86/mm/pageattr.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index e2d4b25c7aa44..abbe3e93ec266 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -687,6 +687,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, pgprot_t ref_prot; spin_lock(&pgd_lock); + preempt_disable(); /* * Check for races, another CPU might have split this page * up for us already: @@ -694,6 +695,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, tmp = _lookup_address_cpa(cpa, address, &level); if (tmp != kpte) { spin_unlock(&pgd_lock); + preempt_enable(); return 1; } @@ -727,6 +729,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, default: spin_unlock(&pgd_lock); + preempt_enable(); return 1; } @@ -764,6 +767,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, * going on. */ __flush_tlb_all(); + preempt_enable(); spin_unlock(&pgd_lock); return 0; -- 2.20.0
