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authorAndy Lutomirski <luto@kernel.org>2016-05-03 10:31:51 -0700
committerIngo Molnar <mingo@kernel.org>2016-05-04 08:34:14 +0200
commit0318bc8a919ded355eaa5078689924a15c1bf52a (patch)
treeff92690aed065f4e6078d66e6f9c5c8374359c37
parent158b67b5c5ccda9b909f18028a3cd17185ca1efd (diff)
signals/sigaltstack: Report current flag bits in sigaltstack()
sigaltstack()'s reported previous state uses a somewhat odd convention, but the concept of flag bits is new, and we can do the flag bits sensibly. Specifically, let's just report them directly. This will allow saving and restoring the sigaltstack state using sigaltstack() to work correctly. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Amanieu d'Antras <amanieu@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Stas Sergeev <stsp@list.ru> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: linux-api@vger.kernel.org Link: http://lkml.kernel.org/r/94b291ec9fd47741a9264851e316e158ded0b00d.1462296606.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/signal.c3
-rw-r--r--tools/testing/selftests/sigaltstack/sas.c19
2 files changed, 18 insertions, 4 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index bf97ea5775ae..ab122a2cee41 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3099,7 +3099,8 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
oss.ss_sp = (void __user *) current->sas_ss_sp;
oss.ss_size = current->sas_ss_size;
- oss.ss_flags = sas_ss_flags(sp);
+ oss.ss_flags = sas_ss_flags(sp) |
+ (current->sas_ss_flags & SS_FLAG_BITS);
if (uss) {
void __user *ss_sp;
diff --git a/tools/testing/selftests/sigaltstack/sas.c b/tools/testing/selftests/sigaltstack/sas.c
index a98c3ef8141f..4280d0699792 100644
--- a/tools/testing/selftests/sigaltstack/sas.c
+++ b/tools/testing/selftests/sigaltstack/sas.c
@@ -113,6 +113,19 @@ int main(void)
perror("mmap()");
return EXIT_FAILURE;
}
+
+ err = sigaltstack(NULL, &stk);
+ if (err) {
+ perror("[FAIL]\tsigaltstack()");
+ exit(EXIT_FAILURE);
+ }
+ if (stk.ss_flags == SS_DISABLE) {
+ printf("[OK]\tInitial sigaltstack state was SS_DISABLE\n");
+ } else {
+ printf("[FAIL]\tInitial sigaltstack state was %i; should have been SS_DISABLE\n", stk.ss_flags);
+ return EXIT_FAILURE;
+ }
+
stk.ss_sp = sstack;
stk.ss_size = SIGSTKSZ;
stk.ss_flags = SS_ONSTACK | SS_AUTODISARM;
@@ -151,12 +164,12 @@ int main(void)
perror("[FAIL]\tsigaltstack()");
exit(EXIT_FAILURE);
}
- if (stk.ss_flags != 0) {
- printf("[FAIL]\tss_flags=%i, should be 0\n",
+ if (stk.ss_flags != SS_AUTODISARM) {
+ printf("[FAIL]\tss_flags=%i, should be SS_AUTODISARM\n",
stk.ss_flags);
exit(EXIT_FAILURE);
}
- printf("[OK]\tsigaltstack is enabled after signal\n");
+ printf("[OK]\tsigaltstack is still SS_AUTODISARM after signal\n");
printf("[OK]\tTest passed\n");
return 0;