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 panics 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]>
---
Changes in v2:
- Code style clean up, per Steve
- Commit message typo fix, per Steve
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..4f91a81dd838 100644
--- a/kernel/trace/tracing_map.c
+++ b/kernel/trace/tracing_map.c
@@ -834,20 +834,26 @@ 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)
{
+ 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_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;
const struct tracing_map_elt *elt_a, *elt_b;
struct tracing_map_sort_key *sort_key;
struct tracing_map_field *field;
@@ -855,8 +861,8 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
void *val_a, *val_b;
int ret = 0;
- elt_a = (*a)->elt;
- elt_b = (*b)->elt;
+ elt_a = a->elt;
+ elt_b = b->elt;
sort_key = &elt_a->map->sort_key;
@@ -873,9 +879,12 @@ 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_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;
const struct tracing_map_elt *elt_a, *elt_b;
struct tracing_map_sort_key *sort_key;
struct tracing_map_field *field;
@@ -883,8 +892,8 @@ static int cmp_entries_key(const struct tracing_map_sort_entry **a,
void *val_a, *val_b;
int ret = 0;
- 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: 348949d9a4440abdab3b1dc99a9bb660e8c7da7c
--
2.33.0.1079.g6e70778dc9-goog
Hi Kalesh,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on 348949d9a4440abdab3b1dc99a9bb660e8c7da7c]
url: https://github.com/0day-ci/linux/commits/Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
base: 348949d9a4440abdab3b1dc99a9bb660e8c7da7c
config: powerpc-allmodconfig (attached as .config)
compiler: powerpc-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
git checkout aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=powerpc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
kernel/trace/tracing_map.c: In function 'cmp_entries_dup':
>> kernel/trace/tracing_map.c:839:52: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
839 | const struct tracing_map_sort_entry **pa = A;
| ^
kernel/trace/tracing_map.c:840:52: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
840 | const struct tracing_map_sort_entry **pb = B;
| ^
kernel/trace/tracing_map.c: In function 'cmp_entries_sum':
kernel/trace/tracing_map.c:853:52: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
853 | const struct tracing_map_sort_entry **pa = A;
| ^
kernel/trace/tracing_map.c:854:52: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
854 | const struct tracing_map_sort_entry **pb = B;
| ^
kernel/trace/tracing_map.c: In function 'cmp_entries_key':
kernel/trace/tracing_map.c:884:52: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
884 | const struct tracing_map_sort_entry **pa = A;
| ^
kernel/trace/tracing_map.c:885:52: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]
885 | const struct tracing_map_sort_entry **pb = B;
| ^
cc1: all warnings being treated as errors
vim +/const +839 kernel/trace/tracing_map.c
836
837 static int cmp_entries_dup(const void *A, const void *B)
838 {
> 839 const struct tracing_map_sort_entry **pa = A;
840 const struct tracing_map_sort_entry **pb = B;
841 const struct tracing_map_sort_entry *a = *pa;
842 const struct tracing_map_sort_entry *b = *pb;
843 int ret = 0;
844
845 if (memcmp(a->key, b->key, a->elt->map->key_size))
846 ret = 1;
847
848 return ret;
849 }
850
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi Kalesh,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on 348949d9a4440abdab3b1dc99a9bb660e8c7da7c]
url: https://github.com/0day-ci/linux/commits/Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
base: 348949d9a4440abdab3b1dc99a9bb660e8c7da7c
config: x86_64-buildonly-randconfig-r002-20211013 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6c76d0101193aa4eb891a6954ff047eda2f9cf71)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
git checkout aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
>> kernel/trace/tracing_map.c:839:40: error: initializing 'const struct tracing_map_sort_entry **' with an expression of type 'const void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
const struct tracing_map_sort_entry **pa = A;
^ ~
kernel/trace/tracing_map.c:840:40: error: initializing 'const struct tracing_map_sort_entry **' with an expression of type 'const void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
const struct tracing_map_sort_entry **pb = B;
^ ~
kernel/trace/tracing_map.c:853:40: error: initializing 'const struct tracing_map_sort_entry **' with an expression of type 'const void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
const struct tracing_map_sort_entry **pa = A;
^ ~
kernel/trace/tracing_map.c:854:40: error: initializing 'const struct tracing_map_sort_entry **' with an expression of type 'const void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
const struct tracing_map_sort_entry **pb = B;
^ ~
kernel/trace/tracing_map.c:884:40: error: initializing 'const struct tracing_map_sort_entry **' with an expression of type 'const void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
const struct tracing_map_sort_entry **pa = A;
^ ~
kernel/trace/tracing_map.c:885:40: error: initializing 'const struct tracing_map_sort_entry **' with an expression of type 'const void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
const struct tracing_map_sort_entry **pb = B;
^ ~
6 errors generated.
vim +839 kernel/trace/tracing_map.c
836
837 static int cmp_entries_dup(const void *A, const void *B)
838 {
> 839 const struct tracing_map_sort_entry **pa = A;
840 const struct tracing_map_sort_entry **pb = B;
841 const struct tracing_map_sort_entry *a = *pa;
842 const struct tracing_map_sort_entry *b = *pb;
843 int ret = 0;
844
845 if (memcmp(a->key, b->key, a->elt->map->key_size))
846 ret = 1;
847
848 return ret;
849 }
850
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi Kalesh,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on 348949d9a4440abdab3b1dc99a9bb660e8c7da7c]
url: https://github.com/0day-ci/linux/commits/Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
base: 348949d9a4440abdab3b1dc99a9bb660e8c7da7c
config: arm64-randconfig-r005-20211014 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
git checkout aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arm64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
kernel/trace/tracing_map.c: In function 'cmp_entries_dup':
>> kernel/trace/tracing_map.c:839:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
839 | const struct tracing_map_sort_entry **pa = A;
| ^
kernel/trace/tracing_map.c:840:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
840 | const struct tracing_map_sort_entry **pb = B;
| ^
kernel/trace/tracing_map.c: In function 'cmp_entries_sum':
kernel/trace/tracing_map.c:853:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
853 | const struct tracing_map_sort_entry **pa = A;
| ^
kernel/trace/tracing_map.c:854:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
854 | const struct tracing_map_sort_entry **pb = B;
| ^
kernel/trace/tracing_map.c: In function 'cmp_entries_key':
kernel/trace/tracing_map.c:884:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
884 | const struct tracing_map_sort_entry **pa = A;
| ^
kernel/trace/tracing_map.c:885:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
885 | const struct tracing_map_sort_entry **pb = B;
| ^
vim +/const +839 kernel/trace/tracing_map.c
836
837 static int cmp_entries_dup(const void *A, const void *B)
838 {
> 839 const struct tracing_map_sort_entry **pa = A;
840 const struct tracing_map_sort_entry **pb = B;
841 const struct tracing_map_sort_entry *a = *pa;
842 const struct tracing_map_sort_entry *b = *pb;
843 int ret = 0;
844
845 if (memcmp(a->key, b->key, a->elt->map->key_size))
846 ret = 1;
847
848 return ret;
849 }
850
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Thu, Oct 14, 2021 at 4:13 AM kernel test robot <[email protected]> wrote:
>
> Hi Kalesh,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on 348949d9a4440abdab3b1dc99a9bb660e8c7da7c]
>
> url: https://github.com/0day-ci/linux/commits/Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
> base: 348949d9a4440abdab3b1dc99a9bb660e8c7da7c
> config: arm64-randconfig-r005-20211014 (attached as .config)
> compiler: aarch64-linux-gcc (GCC) 11.2.0
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://github.com/0day-ci/linux/commit/aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Kalesh-Singh/tracing-cfi-Fix-cmp_entries_-functions-signature-mismatch/20211014-093824
> git checkout aca9efb61e0559ff7abff8c8bce5e1a65a73ccce
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arm64
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All warnings (new ones prefixed by >>):
>
> kernel/trace/tracing_map.c: In function 'cmp_entries_dup':
> >> kernel/trace/tracing_map.c:839:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 839 | const struct tracing_map_sort_entry **pa = A;
> | ^
> kernel/trace/tracing_map.c:840:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 840 | const struct tracing_map_sort_entry **pb = B;
> | ^
> kernel/trace/tracing_map.c: In function 'cmp_entries_sum':
> kernel/trace/tracing_map.c:853:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 853 | const struct tracing_map_sort_entry **pa = A;
> | ^
> kernel/trace/tracing_map.c:854:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 854 | const struct tracing_map_sort_entry **pb = B;
> | ^
> kernel/trace/tracing_map.c: In function 'cmp_entries_key':
> kernel/trace/tracing_map.c:884:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 884 | const struct tracing_map_sort_entry **pa = A;
> | ^
> kernel/trace/tracing_map.c:885:52: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 885 | const struct tracing_map_sort_entry **pb = B;
> | ^
>
I posted a v3 to address these:
https://lore.kernel.org/r/[email protected]/
Thanks,
Kalesh
>
> vim +/const +839 kernel/trace/tracing_map.c
>
> 836
> 837 static int cmp_entries_dup(const void *A, const void *B)
> 838 {
> > 839 const struct tracing_map_sort_entry **pa = A;
> 840 const struct tracing_map_sort_entry **pb = B;
> 841 const struct tracing_map_sort_entry *a = *pa;
> 842 const struct tracing_map_sort_entry *b = *pb;
> 843 int ret = 0;
> 844
> 845 if (memcmp(a->key, b->key, a->elt->map->key_size))
> 846 ret = 1;
> 847
> 848 return ret;
> 849 }
> 850
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/[email protected]
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].