On May 7, 2016 8:02 AM, "Stas Sergeev" <[email protected]> wrote: > > 03.05.2016 20:31, Andy Lutomirski пишет: > >> The handling for old kernels was wrong. Fix it. >> >> Reported-by: Ingo Molnar <[email protected]> >> Cc: Stas Sergeev <[email protected]> >> Cc: Al Viro <[email protected]> >> Cc: Andrew Morton <[email protected]> >> Cc: Andy Lutomirski <[email protected]> >> Cc: Borislav Petkov <[email protected]> >> Cc: Brian Gerst <[email protected]> >> Cc: Denys Vlasenko <[email protected]> >> Cc: H. Peter Anvin <[email protected]> >> Cc: Linus Torvalds <[email protected]> >> Cc: Oleg Nesterov <[email protected]> >> Cc: Pavel Emelyanov <[email protected]> >> Cc: Peter Zijlstra <[email protected]> >> Cc: Shuah Khan <[email protected]> >> Cc: Thomas Gleixner <[email protected]> >> Cc: [email protected] >> Cc: [email protected] >> Signed-off-by: Andy Lutomirski <[email protected]> >> --- >> tools/testing/selftests/sigaltstack/sas.c | 21 ++++++++++++++------- >> 1 file changed, 14 insertions(+), 7 deletions(-) >> >> diff --git a/tools/testing/selftests/sigaltstack/sas.c >> b/tools/testing/selftests/sigaltstack/sas.c >> index 57da8bfde60b..a98c3ef8141f 100644 >> --- a/tools/testing/selftests/sigaltstack/sas.c >> +++ b/tools/testing/selftests/sigaltstack/sas.c >> @@ -15,6 +15,7 @@ >> #include <alloca.h> >> #include <string.h> >> #include <assert.h> >> +#include <errno.h> >> #ifndef SS_AUTODISARM >> #define SS_AUTODISARM (1 << 4) >> @@ -117,13 +118,19 @@ int main(void) >> stk.ss_flags = SS_ONSTACK | SS_AUTODISARM; >> err = sigaltstack(&stk, NULL); >> if (err) { >> - perror("[FAIL]\tsigaltstack(SS_ONSTACK | SS_AUTODISARM)"); >> - stk.ss_flags = SS_ONSTACK; >> - } >> - err = sigaltstack(&stk, NULL); >> - if (err) { >> - perror("[FAIL]\tsigaltstack(SS_ONSTACK)"); >> - return EXIT_FAILURE; >> + if (errno == EINVAL) { >> + printf("[NOTE]\tThe running kernel doesn't support >> SS_AUTODISARM\n"); >> + /* >> + * If test cases for the !SS_AUTODISARM variant were >> + * added, we could still run them. We don't have any >> + * test cases like that yet, so just exit and report >> + * success. >> + */ > > But that was the point, please see how it handles the > old kernels: > > $ ./sas > [FAIL] sigaltstack(SS_ONSTACK | SS_AUTODISARM): Invalid argument > [RUN] signal USR1 > [FAIL] ss_flags=1, should be SS_DISABLE > [RUN] switched to user ctx > [RUN] signal USR2 > [FAIL] sigaltstack re-used > [FAIL] Stack corrupted > [RUN] Aborting
This is useful as a demonstration of why the feature is useful, but it doesn't indicate that anything is wrong with old kernels per she. That's why I changed it to simply report that the feature is missing.
