x86/ldt: Fix off by one in get_segment_base()

[karo-tx-linux.git] / arch / x86 / events / core.c

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 8e3db8f642a7a02dd8f99db3a25dedbfd1deb01a..939050169d122c9d129219be27c09e6a9a9ef443 100644 (file)
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2114,7 +2114,7 @@ static void refresh_pce(void *ignored)
        load_mm_cr4(this_cpu_read(cpu_tlbstate.loaded_mm));
 }
 
-static void x86_pmu_event_mapped(struct perf_event *event)
+static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm)
 {
        if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
                return;
@@ -2129,22 +2129,20 @@ static void x86_pmu_event_mapped(struct perf_event *event)
         * For now, this can't happen because all callers hold mmap_sem
         * for write.  If this changes, we'll need a different solution.
         */
-       lockdep_assert_held_exclusive(&current->mm->mmap_sem);
+       lockdep_assert_held_exclusive(&mm->mmap_sem);
 
-       if (atomic_inc_return(&current->mm->context.perf_rdpmc_allowed) == 1)
-               on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1);
+       if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)
+               on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
 }
 
-static void x86_pmu_event_unmapped(struct perf_event *event)
+static void x86_pmu_event_unmapped(struct perf_event *event, struct mm_struct *mm)
 {
-       if (!current->mm)
-               return;
 
        if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
                return;
 
-       if (atomic_dec_and_test(&current->mm->context.perf_rdpmc_allowed))
-               on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1);
+       if (atomic_dec_and_test(&mm->context.perf_rdpmc_allowed))
+               on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
 }
 
 static int x86_pmu_event_idx(struct perf_event *event)
@@ -2337,12 +2335,9 @@ static unsigned long get_segment_base(unsigned int segment)
 #ifdef CONFIG_MODIFY_LDT_SYSCALL
                struct ldt_struct *ldt;
 
-               if (idx > LDT_ENTRIES)
-                       return 0;
-
                /* IRQs are off, so this synchronizes with smp_store_release */
                ldt = lockless_dereference(current->active_mm->context.ldt);
-               if (!ldt || idx > ldt->nr_entries)
+               if (!ldt || idx >= ldt->nr_entries)
                        return 0;
 
                desc = &ldt->entries[idx];
@@ -2350,7 +2345,7 @@ static unsigned long get_segment_base(unsigned int segment)
                return 0;
 #endif
        } else {
-               if (idx > GDT_ENTRIES)
+               if (idx >= GDT_ENTRIES)
                        return 0;
 
                desc = raw_cpu_ptr(gdt_page.gdt) + idx;