3.1.0-stable causes compilation warnings

[DrakoDom]

In kernel 6.4.8, I noticed some warnings in the latest version of bore-stable that didn't appear in the previous 3.0.0-stable. I'm using Clang 16.0.6 for compilation, so these warnings may not appear with GCC.

kernel/sched/fair.c:163:9: warning: comparison of distinct pointer types ('typeof (((40UL << 8) - 1)) *' (aka 'unsigned long *') and 'typeof (scaled_penalty) *' (aka 'unsigned int *')) [-Wcompare-distinct-pointer-types]
        return min(MAX_BURST_PENALTY, scaled_penalty);
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/minmax.h:67:19: note: expanded from macro 'min'
#define min(x, y)       __careful_cmp(x, y, <)
                        ^~~~~~~~~~~~~~~~~~~~~~
./include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
        __builtin_choose_expr(__safe_cmp(x, y), \
                              ^~~~~~~~~~~~~~~~
./include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                (__typecheck(x, y) && __no_side_effects(x, y))
                 ^~~~~~~~~~~~~~~~~
./include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
        (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                   ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
kernel/sched/fair.c:1067:20: warning: comparison of distinct pointer types ('typeof (1) *' (aka 'int *') and 'typeof (__calc_delta_fair(delta_exec, curr, false)) *' (aka 'unsigned long long *')) [-Wcompare-distinct-pointer-types]
        curr->vruntime += max(1, calc_delta_fair(delta_exec, curr));
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/minmax.h:74:19: note: expanded from macro 'max'
#define max(x, y)       __careful_cmp(x, y, >)
                        ^~~~~~~~~~~~~~~~~~~~~~
./include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
        __builtin_choose_expr(__safe_cmp(x, y), \
                              ^~~~~~~~~~~~~~~~
./include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                (__typecheck(x, y) && __no_side_effects(x, y))
                 ^~~~~~~~~~~~~~~~~
./include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
        (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                   ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~

[firelzrd]

My bad.
Will Clang silence by appending 'ULL' to specify it's an u64?

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1087,7 +1087,7 @@ static void update_curr(struct cfs_rq *cfs_rq)
 	curr->burst_time += delta_exec;
 	update_burst_penalty(curr);
 #endif // CONFIG_SCHED_BORE
-	curr->vruntime += max(1, calc_delta_fair(delta_exec, curr));
+	curr->vruntime += max(1ULL, calc_delta_fair(delta_exec, curr));
 	update_min_vruntime(cfs_rq);
 
 	if (entity_is_task(curr)) {

[sirlucjan]

@mu I checked it and it seems to have partially solved the problem, but some warnings still occur.

kernel/sched/fair.c:186:9: warning: comparison of distinct pointer types ('typeof (((40UL << 8) - 1)) *' (aka 'unsigned long *') and 'typeof (scaled_penalty) *' (aka 'unsigned int *')) [-Wcompare-distinct-pointer-types]
        return min(MAX_BURST_PENALTY, scaled_penalty);
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/minmax.h:67:19: note: expanded from macro 'min'
#define min(x, y)       __careful_cmp(x, y, <)
                        ^~~~~~~~~~~~~~~~~~~~~~
./include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
        __builtin_choose_expr(__safe_cmp(x, y), \
                              ^~~~~~~~~~~~~~~~
./include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                (__typecheck(x, y) && __no_side_effects(x, y))
                 ^~~~~~~~~~~~~~~~~
./include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
        (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))

[firelzrd]

Thank you for testing.

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -164,7 +164,7 @@ static int three          = 3;
 static int sixty_four     = 64;
 static int maxval_12_bits = 4095;
 
-#define MAX_BURST_PENALTY ((40UL << 8) - 1)
+#define MAX_BURST_PENALTY ((40U << 8) - 1)
 
 static inline u32 log2plus1_u64_u32f8(u64 v) {
 	x32 result;

Will this do?

[sirlucjan]

Yay :D

  CC      kernel/vhost_task.o
  CC      mm/mmzone.o
  CC      arch/x86/hyperv/mmu.o
  CC      kernel/sched/core.o
  CC      mm/vmstat.o
  CC      fs/super.o
  CC      arch/x86/hyperv/nested.o
  CC      mm/backing-dev.o
  CC      fs/char_dev.o
  CC      arch/x86/hyperv/irqdomain.o
  CC      arch/x86/hyperv/ivm.o
  CC      fs/stat.o
  CC      mm/mm_init.o
  CC      arch/x86/hyperv/hv_apic.o

I used both fixes and it looks like CLANG no longer shows warnings. I also checked GG and there is nothing there either.

[firelzrd]

Thank you for your assistance!

[DrakoDom]

Those two patches seem to have eliminated the warnings for me too. Thank you for your help.

Closing now.

[firelzrd]

Thank you for the report!