2021-09-23 17:11:53

by Kalesh Singh

Subject: [PATCH] tracing/cfi: Fix cmp_entries_* functions signature mismatch

If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
the kernel to panic due to failed CFI check.

1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
2. cat >> events/sched/sched_switch/hist
3. kernel panices on attempting to read hist

This happens because the sort() function expects a generic
int (*)(const void *, const void *) pointer for the compare function.
To prevent this CFI failure, change tracing map cmp_entries_* function
signatures to match this.

Signed-off-by: Kalesh Singh <[email protected]>
---
kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++----------------
1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
index d6bddb157ef2..a8c80ebbf9da 100644
--- a/kernel/trace/tracing_map.c
+++ b/kernel/trace/tracing_map.c
@@ -834,19 +834,21 @@ int tracing_map_init(struct tracing_map *map)
return err;
}

-static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
- const struct tracing_map_sort_entry **b)
+static int cmp_entries_dup(const void *__a, const void *__b)
{
int ret = 0;
+ const struct tracing_map_sort_entry *a
+ = *(const struct tracing_map_sort_entry **)__a;
+ const struct tracing_map_sort_entry *b
+ = *(const struct tracing_map_sort_entry **)__b;

- if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
+ if (memcmp(a->key, b->key, a->elt->map->key_size))
ret = 1;

return ret;
}

-static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
- const struct tracing_map_sort_entry **b)
+static int cmp_entries_sum(const void *__a, const void *__b)
{
const struct tracing_map_elt *elt_a, *elt_b;
struct tracing_map_sort_key *sort_key;
@@ -854,9 +856,13 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
tracing_map_cmp_fn_t cmp_fn;
void *val_a, *val_b;
int ret = 0;
+ const struct tracing_map_sort_entry *a
+ = *(const struct tracing_map_sort_entry **)__a;
+ const struct tracing_map_sort_entry *b
+ = *(const struct tracing_map_sort_entry **)__b;

- elt_a = (*a)->elt;
- elt_b = (*b)->elt;
+ elt_a = a->elt;
+ elt_b = b->elt;

sort_key = &elt_a->map->sort_key;

@@ -873,8 +879,7 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
return ret;
}

-static int cmp_entries_key(const struct tracing_map_sort_entry **a,
- const struct tracing_map_sort_entry **b)
+static int cmp_entries_key(const void *__a, const void *__b)
{
const struct tracing_map_elt *elt_a, *elt_b;
struct tracing_map_sort_key *sort_key;
@@ -882,9 +887,13 @@ static int cmp_entries_key(const struct tracing_map_sort_entry **a,
tracing_map_cmp_fn_t cmp_fn;
void *val_a, *val_b;
int ret = 0;
+ const struct tracing_map_sort_entry *a
+ = *(const struct tracing_map_sort_entry **)__a;
+ const struct tracing_map_sort_entry *b
+ = *(const struct tracing_map_sort_entry **)__b;

- elt_a = (*a)->elt;
- elt_b = (*b)->elt;
+ elt_a = a->elt;
+ elt_b = b->elt;

sort_key = &elt_a->map->sort_key;

@@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
struct tracing_map_sort_key *primary_key,
struct tracing_map_sort_key *secondary_key)
{
- int (*primary_fn)(const struct tracing_map_sort_entry **,
- const struct tracing_map_sort_entry **);
- int (*secondary_fn)(const struct tracing_map_sort_entry **,
- const struct tracing_map_sort_entry **);
+ int (*primary_fn)(const void *, const void *);
+ int (*secondary_fn)(const void *, const void *);
unsigned i, start = 0, n_sub = 1;

if (is_key(map, primary_key->field_idx))
@@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
unsigned int n_sort_keys,
struct tracing_map_sort_entry ***sort_entries)
{
- int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
- const struct tracing_map_sort_entry **);
+ int (*cmp_entries_fn)(const void *, const void *);
struct tracing_map_sort_entry *sort_entry, **entries;
int i, n_entries, ret;


base-commit: 58e2cf5d794616b84f591d4d1276c8953278ce24
--
2.33.0.685.g46640cef36-goog

2021-09-25 01:07:09

by Sami Tolvanen

Subject: Re: [PATCH] tracing/cfi: Fix cmp_entries_* functions signature mismatch

Hi Kalesh,

On Thu, Sep 23, 2021 at 10:09 AM Kalesh Singh <[email protected]> wrote:
>
> If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
> the kernel to panic due to failed CFI check.
>
> 1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
> 2. cat >> events/sched/sched_switch/hist
> 3. kernel panices on attempting to read hist
>
> This happens because the sort() function expects a generic
> int (*)(const void *, const void *) pointer for the compare function.
> To prevent this CFI failure, change tracing map cmp_entries_* function
> signatures to match this.
>
> Signed-off-by: Kalesh Singh <[email protected]>
> ---
> kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++----------------
> 1 file changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
> index d6bddb157ef2..a8c80ebbf9da 100644
> --- a/kernel/trace/tracing_map.c
> +++ b/kernel/trace/tracing_map.c
> @@ -834,19 +834,21 @@ int tracing_map_init(struct tracing_map *map)
> return err;
> }
>
> -static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
> - const struct tracing_map_sort_entry **b)
> +static int cmp_entries_dup(const void *__a, const void *__b)
> {
> int ret = 0;
> + const struct tracing_map_sort_entry *a
> + = *(const struct tracing_map_sort_entry **)__a;
> + const struct tracing_map_sort_entry *b
> + = *(const struct tracing_map_sort_entry **)__b;
>
> - if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
> + if (memcmp(a->key, b->key, a->elt->map->key_size))
> ret = 1;
>
> return ret;
> }
>
> -static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> - const struct tracing_map_sort_entry **b)
> +static int cmp_entries_sum(const void *__a, const void *__b)
> {
> const struct tracing_map_elt *elt_a, *elt_b;
> struct tracing_map_sort_key *sort_key;
> @@ -854,9 +856,13 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> tracing_map_cmp_fn_t cmp_fn;
> void *val_a, *val_b;
> int ret = 0;
> + const struct tracing_map_sort_entry *a
> + = *(const struct tracing_map_sort_entry **)__a;
> + const struct tracing_map_sort_entry *b
> + = *(const struct tracing_map_sort_entry **)__b;
>
> - elt_a = (*a)->elt;
> - elt_b = (*b)->elt;
> + elt_a = a->elt;
> + elt_b = b->elt;
>
> sort_key = &elt_a->map->sort_key;
>
> @@ -873,8 +879,7 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> return ret;
> }
>
> -static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> - const struct tracing_map_sort_entry **b)
> +static int cmp_entries_key(const void *__a, const void *__b)
> {
> const struct tracing_map_elt *elt_a, *elt_b;
> struct tracing_map_sort_key *sort_key;
> @@ -882,9 +887,13 @@ static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> tracing_map_cmp_fn_t cmp_fn;
> void *val_a, *val_b;
> int ret = 0;
> + const struct tracing_map_sort_entry *a
> + = *(const struct tracing_map_sort_entry **)__a;
> + const struct tracing_map_sort_entry *b
> + = *(const struct tracing_map_sort_entry **)__b;
>
> - elt_a = (*a)->elt;
> - elt_b = (*b)->elt;
> + elt_a = a->elt;
> + elt_b = b->elt;
>
> sort_key = &elt_a->map->sort_key;
>
> @@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
> struct tracing_map_sort_key *primary_key,
> struct tracing_map_sort_key *secondary_key)
> {
> - int (*primary_fn)(const struct tracing_map_sort_entry **,
> - const struct tracing_map_sort_entry **);
> - int (*secondary_fn)(const struct tracing_map_sort_entry **,
> - const struct tracing_map_sort_entry **);
> + int (*primary_fn)(const void *, const void *);
> + int (*secondary_fn)(const void *, const void *);
> unsigned i, start = 0, n_sub = 1;
>
> if (is_key(map, primary_key->field_idx))
> @@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
> unsigned int n_sort_keys,
> struct tracing_map_sort_entry ***sort_entries)
> {
> - int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
> - const struct tracing_map_sort_entry **);
> + int (*cmp_entries_fn)(const void *, const void *);
> struct tracing_map_sort_entry *sort_entry, **entries;
> int i, n_entries, ret;
>
>

Thanks for the patch! This looks correct to me and fixes the function
type mismatch that trips CFI.

Reviewed-by: Sami Tolvanen <[email protected]>

Sami

2021-09-27 18:16:57

by Kalesh Singh

Subject: Re: [PATCH] tracing/cfi: Fix cmp_entries_* functions signature mismatch

On Fri, Sep 24, 2021 at 8:20 AM Sami Tolvanen <[email protected]> wrote:
>
> Hi Kalesh,
>
> On Thu, Sep 23, 2021 at 10:09 AM Kalesh Singh <[email protected]> wrote:
> >
> > If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
> > the kernel to panic due to failed CFI check.
> >
> > 1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
> > 2. cat >> events/sched/sched_switch/hist
> > 3. kernel panices on attempting to read hist
> >
> > This happens because the sort() function expects a generic
> > int (*)(const void *, const void *) pointer for the compare function.
> > To prevent this CFI failure, change tracing map cmp_entries_* function
> > signatures to match this.
> >
> > Signed-off-by: Kalesh Singh <[email protected]>
> > ---
> > kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++----------------
> > 1 file changed, 23 insertions(+), 17 deletions(-)
> >
> > diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
> > index d6bddb157ef2..a8c80ebbf9da 100644
> > --- a/kernel/trace/tracing_map.c
> > +++ b/kernel/trace/tracing_map.c
> > @@ -834,19 +834,21 @@ int tracing_map_init(struct tracing_map *map)
> > return err;
> > }
> >
> > -static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
> > - const struct tracing_map_sort_entry **b)
> > +static int cmp_entries_dup(const void *__a, const void *__b)
> > {
> > int ret = 0;
> > + const struct tracing_map_sort_entry *a
> > + = *(const struct tracing_map_sort_entry **)__a;
> > + const struct tracing_map_sort_entry *b
> > + = *(const struct tracing_map_sort_entry **)__b;
> >
> > - if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
> > + if (memcmp(a->key, b->key, a->elt->map->key_size))
> > ret = 1;
> >
> > return ret;
> > }
> >
> > -static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> > - const struct tracing_map_sort_entry **b)
> > +static int cmp_entries_sum(const void *__a, const void *__b)
> > {
> > const struct tracing_map_elt *elt_a, *elt_b;
> > struct tracing_map_sort_key *sort_key;
> > @@ -854,9 +856,13 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> > tracing_map_cmp_fn_t cmp_fn;
> > void *val_a, *val_b;
> > int ret = 0;
> > + const struct tracing_map_sort_entry *a
> > + = *(const struct tracing_map_sort_entry **)__a;
> > + const struct tracing_map_sort_entry *b
> > + = *(const struct tracing_map_sort_entry **)__b;
> >
> > - elt_a = (*a)->elt;
> > - elt_b = (*b)->elt;
> > + elt_a = a->elt;
> > + elt_b = b->elt;
> >
> > sort_key = &elt_a->map->sort_key;
> >
> > @@ -873,8 +879,7 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> > return ret;
> > }
> >
> > -static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> > - const struct tracing_map_sort_entry **b)
> > +static int cmp_entries_key(const void *__a, const void *__b)
> > {
> > const struct tracing_map_elt *elt_a, *elt_b;
> > struct tracing_map_sort_key *sort_key;
> > @@ -882,9 +887,13 @@ static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> > tracing_map_cmp_fn_t cmp_fn;
> > void *val_a, *val_b;
> > int ret = 0;
> > + const struct tracing_map_sort_entry *a
> > + = *(const struct tracing_map_sort_entry **)__a;
> > + const struct tracing_map_sort_entry *b
> > + = *(const struct tracing_map_sort_entry **)__b;
> >
> > - elt_a = (*a)->elt;
> > - elt_b = (*b)->elt;
> > + elt_a = a->elt;
> > + elt_b = b->elt;
> >
> > sort_key = &elt_a->map->sort_key;
> >
> > @@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
> > struct tracing_map_sort_key *primary_key,
> > struct tracing_map_sort_key *secondary_key)
> > {
> > - int (*primary_fn)(const struct tracing_map_sort_entry **,
> > - const struct tracing_map_sort_entry **);
> > - int (*secondary_fn)(const struct tracing_map_sort_entry **,
> > - const struct tracing_map_sort_entry **);
> > + int (*primary_fn)(const void *, const void *);
> > + int (*secondary_fn)(const void *, const void *);
> > unsigned i, start = 0, n_sub = 1;
> >
> > if (is_key(map, primary_key->field_idx))
> > @@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
> > unsigned int n_sort_keys,
> > struct tracing_map_sort_entry ***sort_entries)
> > {
> > - int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
> > - const struct tracing_map_sort_entry **);
> > + int (*cmp_entries_fn)(const void *, const void *);
> > struct tracing_map_sort_entry *sort_entry, **entries;
> > int i, n_entries, ret;
> >
> >
>
> Thanks for the patch! This looks correct to me and fixes the function
> type mismatch that trips CFI.
>
> Reviewed-by: Sami Tolvanen <[email protected]>

Thanks for the review Sami.

Steve, will this get picked up for your tree?

>
> Sami

2021-09-27 21:59:16

by Steven Rostedt

Subject: Re: [PATCH] tracing/cfi: Fix cmp_entries_* functions signature mismatch

On Mon, 27 Sep 2021 11:15:01 -0700
Kalesh Singh <[email protected]> wrote:
> >
> > Thanks for the patch! This looks correct to me and fixes the function
> > type mismatch that trips CFI.
> >
> > Reviewed-by: Sami Tolvanen <[email protected]>
>
> Thanks for the review Sami.
>
> Steve, will this get picked up for your tree?

Yeah, I can pull it through my tree, but as I'm currently traveling, I
can't give a proper ETA on when it will hit. But at the latest, I'll be
looking at all my patch queue next week.

-- Steve

2021-10-13 22:12:02

by Steven Rostedt

Subject: Re: [PATCH] tracing/cfi: Fix cmp_entries_* functions signature mismatch

On Thu, 23 Sep 2021 17:09:07 +0000
Kalesh Singh <[email protected]> wrote:


This finally popped up into my queue (from all my traveling and running of
conferences :-p )


> If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
> the kernel to panic due to failed CFI check.
>
> 1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
> 2. cat >> events/sched/sched_switch/hist

Do you mean:

2. cat events/sched/sched_switch/hist

?

Small nits below.

> 3. kernel panices on attempting to read hist
>
> This happens because the sort() function expects a generic
> int (*)(const void *, const void *) pointer for the compare function.
> To prevent this CFI failure, change tracing map cmp_entries_* function
> signatures to match this.
>
> Signed-off-by: Kalesh Singh <[email protected]>
> ---
> kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++----------------
> 1 file changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
> index d6bddb157ef2..a8c80ebbf9da 100644
> --- a/kernel/trace/tracing_map.c
> +++ b/kernel/trace/tracing_map.c
> @@ -834,19 +834,21 @@ int tracing_map_init(struct tracing_map *map)
> return err;
> }
>
> -static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
> - const struct tracing_map_sort_entry **b)
> +static int cmp_entries_dup(const void *__a, const void *__b)

Instead of __a and __b, have it as:

const void *A, const void *B


> {
> int ret = 0;
> + const struct tracing_map_sort_entry *a
> + = *(const struct tracing_map_sort_entry **)__a;
> + const struct tracing_map_sort_entry *b
> + = *(const struct tracing_map_sort_entry **)__b;

Please put these before the ret, we like to have a "upside down xmas tree"
type of declaration, where longer lines come before shorter ones. Also,
this can be "prettified" as:

const struct tracing_map_sort_entry **pa = A;
const struct tracing_map_sort_entry **pb = B;
const struct tracing_map_sort_entry *a = *pa;
const struct tracing_map_sort_entry *b = *pb;
int ret = 0;

>
> - if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
> + if (memcmp(a->key, b->key, a->elt->map->key_size))
> ret = 1;
>
> return ret;
> }
>
> -static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> - const struct tracing_map_sort_entry **b)
> +static int cmp_entries_sum(const void *__a, const void *__b)
> {
> const struct tracing_map_elt *elt_a, *elt_b;
> struct tracing_map_sort_key *sort_key;
> @@ -854,9 +856,13 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> tracing_map_cmp_fn_t cmp_fn;
> void *val_a, *val_b;
> int ret = 0;
> + const struct tracing_map_sort_entry *a
> + = *(const struct tracing_map_sort_entry **)__a;
> + const struct tracing_map_sort_entry *b
> + = *(const struct tracing_map_sort_entry **)__b;

Same here.

>
> - elt_a = (*a)->elt;
> - elt_b = (*b)->elt;
> + elt_a = a->elt;
> + elt_b = b->elt;
>
> sort_key = &elt_a->map->sort_key;
>
> @@ -873,8 +879,7 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> return ret;
> }
>
> -static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> - const struct tracing_map_sort_entry **b)
> +static int cmp_entries_key(const void *__a, const void *__b)
> {
> const struct tracing_map_elt *elt_a, *elt_b;
> struct tracing_map_sort_key *sort_key;
> @@ -882,9 +887,13 @@ static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> tracing_map_cmp_fn_t cmp_fn;
> void *val_a, *val_b;
> int ret = 0;
> + const struct tracing_map_sort_entry *a
> + = *(const struct tracing_map_sort_entry **)__a;
> + const struct tracing_map_sort_entry *b
> + = *(const struct tracing_map_sort_entry **)__b;

And here.

Thanks, and sorry for the long delay.

-- Steve

>
> - elt_a = (*a)->elt;
> - elt_b = (*b)->elt;
> + elt_a = a->elt;
> + elt_b = b->elt;
>
> sort_key = &elt_a->map->sort_key;
>
> @@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
> struct tracing_map_sort_key *primary_key,
> struct tracing_map_sort_key *secondary_key)
> {
> - int (*primary_fn)(const struct tracing_map_sort_entry **,
> - const struct tracing_map_sort_entry **);
> - int (*secondary_fn)(const struct tracing_map_sort_entry **,
> - const struct tracing_map_sort_entry **);
> + int (*primary_fn)(const void *, const void *);
> + int (*secondary_fn)(const void *, const void *);
> unsigned i, start = 0, n_sub = 1;
>
> if (is_key(map, primary_key->field_idx))
> @@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
> unsigned int n_sort_keys,
> struct tracing_map_sort_entry ***sort_entries)
> {
> - int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
> - const struct tracing_map_sort_entry **);
> + int (*cmp_entries_fn)(const void *, const void *);
> struct tracing_map_sort_entry *sort_entry, **entries;
> int i, n_entries, ret;
>
>
> base-commit: 58e2cf5d794616b84f591d4d1276c8953278ce24

2021-10-14 01:41:22

by Kalesh Singh

Subject: Re: [PATCH] tracing/cfi: Fix cmp_entries_* functions signature mismatch

On Wed, Oct 13, 2021 at 3:08 PM Steven Rostedt <[email protected]> wrote:
>
> On Thu, 23 Sep 2021 17:09:07 +0000
> Kalesh Singh <[email protected]> wrote:
>
>
> This finally popped up into my queue (from all my traveling and running of
> conferences :-p )
>
>
> > If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
> > the kernel to panic due to failed CFI check.
> >
> > 1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
> > 2. cat >> events/sched/sched_switch/hist
>
> Do you mean:
>
> 2. cat events/sched/sched_switch/hist
>
> ?
>
> Small nits below.

Thanks Steve, v2 posted at
https://lore.kernel.org/r/[email protected]/

- Kalesh
>
> > 3. kernel panices on attempting to read hist
> >
> > This happens because the sort() function expects a generic
> > int (*)(const void *, const void *) pointer for the compare function.
> > To prevent this CFI failure, change tracing map cmp_entries_* function
> > signatures to match this.
> >
> > Signed-off-by: Kalesh Singh <[email protected]>
> > ---
> > kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++----------------
> > 1 file changed, 23 insertions(+), 17 deletions(-)
> >
> > diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
> > index d6bddb157ef2..a8c80ebbf9da 100644
> > --- a/kernel/trace/tracing_map.c
> > +++ b/kernel/trace/tracing_map.c
> > @@ -834,19 +834,21 @@ int tracing_map_init(struct tracing_map *map)
> > return err;
> > }
> >
> > -static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
> > - const struct tracing_map_sort_entry **b)
> > +static int cmp_entries_dup(const void *__a, const void *__b)
>
> Instead of __a and __b, have it as:
>
> const void *A, const void *B
>
>
> > {
> > int ret = 0;
> > + const struct tracing_map_sort_entry *a
> > + = *(const struct tracing_map_sort_entry **)__a;
> > + const struct tracing_map_sort_entry *b
> > + = *(const struct tracing_map_sort_entry **)__b;
>
> Please put these before the ret, we like to have a "upside down xmas tree"
> type of declaration, where longer lines come before shorter ones. Also,
> this can be "prettified" as:
>
> const struct tracing_map_sort_entry **pa = A;
> const struct tracing_map_sort_entry **pb = B;
> const struct tracing_map_sort_entry *a = *pa;
> const struct tracing_map_sort_entry *b = *pb;
> int ret = 0;
>
> >
> > - if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
> > + if (memcmp(a->key, b->key, a->elt->map->key_size))
> > ret = 1;
> >
> > return ret;
> > }
> >
> > -static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> > - const struct tracing_map_sort_entry **b)
> > +static int cmp_entries_sum(const void *__a, const void *__b)
> > {
> > const struct tracing_map_elt *elt_a, *elt_b;
> > struct tracing_map_sort_key *sort_key;
> > @@ -854,9 +856,13 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> > tracing_map_cmp_fn_t cmp_fn;
> > void *val_a, *val_b;
> > int ret = 0;
> > + const struct tracing_map_sort_entry *a
> > + = *(const struct tracing_map_sort_entry **)__a;
> > + const struct tracing_map_sort_entry *b
> > + = *(const struct tracing_map_sort_entry **)__b;
>
> Same here.
>
> >
> > - elt_a = (*a)->elt;
> > - elt_b = (*b)->elt;
> > + elt_a = a->elt;
> > + elt_b = b->elt;
> >
> > sort_key = &elt_a->map->sort_key;
> >
> > @@ -873,8 +879,7 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
> > return ret;
> > }
> >
> > -static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> > - const struct tracing_map_sort_entry **b)
> > +static int cmp_entries_key(const void *__a, const void *__b)
> > {
> > const struct tracing_map_elt *elt_a, *elt_b;
> > struct tracing_map_sort_key *sort_key;
> > @@ -882,9 +887,13 @@ static int cmp_entries_key(const struct tracing_map_sort_entry **a,
> > tracing_map_cmp_fn_t cmp_fn;
> > void *val_a, *val_b;
> > int ret = 0;
> > + const struct tracing_map_sort_entry *a
> > + = *(const struct tracing_map_sort_entry **)__a;
> > + const struct tracing_map_sort_entry *b
> > + = *(const struct tracing_map_sort_entry **)__b;
>
> And here.
>
> Thanks, and sorry for the long delay.
>
> -- Steve
>
> >
> > - elt_a = (*a)->elt;
> > - elt_b = (*b)->elt;
> > + elt_a = a->elt;
> > + elt_b = b->elt;
> >
> > sort_key = &elt_a->map->sort_key;
> >
> > @@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
> > struct tracing_map_sort_key *primary_key,
> > struct tracing_map_sort_key *secondary_key)
> > {
> > - int (*primary_fn)(const struct tracing_map_sort_entry **,
> > - const struct tracing_map_sort_entry **);
> > - int (*secondary_fn)(const struct tracing_map_sort_entry **,
> > - const struct tracing_map_sort_entry **);
> > + int (*primary_fn)(const void *, const void *);
> > + int (*secondary_fn)(const void *, const void *);
> > unsigned i, start = 0, n_sub = 1;
> >
> > if (is_key(map, primary_key->field_idx))
> > @@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
> > unsigned int n_sort_keys,
> > struct tracing_map_sort_entry ***sort_entries)
> > {
> > - int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
> > - const struct tracing_map_sort_entry **);
> > + int (*cmp_entries_fn)(const void *, const void *);
> > struct tracing_map_sort_entry *sort_entry, **entries;
> > int i, n_entries, ret;
> >
> >
> > base-commit: 58e2cf5d794616b84f591d4d1276c8953278ce24
>