On 07/25/2014 12:18 PM, Jan Stancek wrote:
> Using glibc wrapper on kernel with smaller CONFIG_NR_CPUS (for example
> 255) leads to segmentation fault in glibc, because it triggers check,
> which is verifying that there are no bits set beyond size of kernel cpu
> mask:
>
> int
> __sched_setaffinity_new (pid_t pid, size_t cpusetsize, const cpu_set_t
> *cpuset)
> ...
> /* We now know the size of the kernel cpumask_t. Make sure the user
> does not request to set a bit beyond that. */
> for (size_t cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
> if (((char *) cpuset)[cnt] != '\0') --> CRASH HERE
>
> Call this syscall directly with ltp_syscall().
>
> Reported-by: Xiaoguang Wang <wangxg.f...@cn.fujitsu.com>
> Signed-off-by: Jan Stancek <jstan...@redhat.com>
Acked-by: Stanislav Kholmanskikh <stanislav.kholmansk...@oracle.com>
> ---
> .../sched_setaffinity/sched_setaffinity01.c | 11 ++++++++---
> 1 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git
> a/testcases/kernel/syscalls/sched_setaffinity/sched_setaffinity01.c
> b/testcases/kernel/syscalls/sched_setaffinity/sched_setaffinity01.c
> index 0ac4478..33a90b8 100644
> --- a/testcases/kernel/syscalls/sched_setaffinity/sched_setaffinity01.c
> +++ b/testcases/kernel/syscalls/sched_setaffinity/sched_setaffinity01.c
> @@ -42,6 +42,7 @@
> #include "usctest.h"
> #include "safe_macros.h"
> #include "sched_setaffinity.h"
> +#include "linux_syscall_numbers.h"
>
> char *TCID = "sched_setaffinity01";
>
> @@ -151,9 +152,13 @@ int main(int argc, char *argv[])
> for (lc = 0; TEST_LOOPING(lc); lc++) {
> tst_count = 0;
> for (i = 0; i < TST_TOTAL; i++) {
> - TEST(sched_setaffinity(*(test_cases[i].pid),
> - *(test_cases[i].mask_size),
> - *(test_cases[i].mask)));
> + /* Avoid calling glibc wrapper function, as it may
> + * try to read/validate data in cpu mask. This test
> + * is passing invalid pointer on purpose. */
> + TEST(ltp_syscall(__NR_sched_setaffinity,
> + *(test_cases[i].pid),
> + *(test_cases[i].mask_size),
> + *(test_cases[i].mask)));
>
> if (TEST_RETURN != -1)
> tst_resm(TFAIL,
>
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