4.14.87-rt50-rc1 stable review patch. If anyone has any objections, please let me know.
------------------ From: Sebastian Andrzej Siewior <[email protected]> [ Upstream commit 45c6ff4811878e5c1c2ae31303cd95cdc6ae2ab4 ] 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 __flush_tlb_all(). Signed-off-by: Sebastian Andrzej Siewior <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]> --- arch/x86/mm/pageattr.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 835620ab435f..57a04ef6fe47 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -661,12 +661,18 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, pgprot_t ref_prot; spin_lock(&pgd_lock); + /* + * Keep preemption disabled after __flush_tlb_all() which expects not be + * preempted during the flush of the local TLB. + */ + preempt_disable(); /* * Check for races, another CPU might have split this page * up for us already: */ tmp = _lookup_address_cpa(cpa, address, &level); if (tmp != kpte) { + preempt_enable(); spin_unlock(&pgd_lock); return 1; } @@ -696,6 +702,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address, break; default: + preempt_enable(); spin_unlock(&pgd_lock); return 1; } @@ -743,6 +750,7 @@ __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; -- 2.19.2
