The following patches make it possible to use swapcontext() in a sighandler that works on sigaltstack. The approach is inspired by Andy Lutomirski's suggestion that sigaltstack should disarm itself after saving into uc_stack: https://lkml.org/lkml/2016/2/1/594 I add the SS_AUTODISARM flag that does exactly that. On sighandler exit, the sigaltstack is restored from uc_stack. Another possible name could be SS_ONESHOT, but, since it gets always re-enabled, I choose SS_AUTODISARM. [PATCH 1/2] sigaltstack: implement SS_AUTODISARM flag This patch implements SS_AUTODISARM flag [PATCH 2/2] selftests: Add test for sigaltstack(SS_AUTODISARM) This patch adds the selftest code for new functionality CC: linux-kernel@xxxxxxxxxxxxxxx CC: linux-api@xxxxxxxxxxxxxxx CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx> CC: Oleg Nesterov <oleg@xxxxxxxxxx> CC: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Diffstat: include/linux/sched.h | 8 + include/linux/signal.h | 4 include/uapi/linux/signal.h | 3 kernel/fork.c | 2 kernel/signal.c | 23 ++-- tools/testing/selftests/Makefile | 1 tools/testing/selftests/sigaltstack/Makefile | 8 + tools/testing/selftests/sigaltstack/sas.c | 151 +++++++++++++++++++++++++++ 8 files changed, 187 insertions(+), 13 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
