On Thu, Nov 18, 2021 at 1:58 PM Eric W. Biederman ebiederm@xmission.com wrote:
SA_IMMUTABLE fixed issues with force_sig_seccomp and the introduction for force_sig_fatal where the exit previously could not be interrupted but now it can. Unfortunately it added that behavior to all force_sig functions under the right conditions which debuggers usage of SIG_TRAP and debuggers handling of SIGSEGV.
Solve that by limiting SA_IMMUTABLE to just the cases that historically debuggers have not been able to intercept.
The first patch changes force_sig_info_to_task to take a flag that requests which behavior is desired.
The second patch adds force_exit_sig which replaces force_fatal_sig in the cases where historically userspace would only find out about the ``signal'' after the process has exited.
The first one with the hunk changing force_fatal_sig removed should be suitable for backporting to v5.15. v5.15 does not implement force_fatal_sig.
This should be enough to fix the regressions.
Kyle if you can double check me that I have properly fixed these issues that would be appreciated.
Any other review or suggestions to improve the names would be appreciated. I think I have named things reasonably well but I am very close to the code so it is easy for me to miss things.
Eric W. Biederman (2): signal: Don't always set SA_IMMUTABLE for forced signals signal: Replace force_fatal_sig with force_exit_sig when in doubt
arch/m68k/kernel/traps.c | 2 +- arch/powerpc/kernel/signal_32.c | 2 +- arch/powerpc/kernel/signal_64.c | 4 ++-- arch/s390/kernel/traps.c | 2 +- arch/sparc/kernel/signal_32.c | 4 ++-- arch/sparc/kernel/windows.c | 2 +- arch/x86/entry/vsyscall/vsyscall_64.c | 2 +- arch/x86/kernel/vm86_32.c | 2 +- include/linux/sched/signal.h | 1 + kernel/entry/syscall_user_dispatch.c | 4 ++-- kernel/signal.c | 36 ++++++++++++++++++++++++++++------- 11 files changed, 42 insertions(+), 19 deletions(-)
Eric
rr's test suite passes with both diffs applied
Tested-by: Kyle Huey khuey@kylehuey.com
- Kyle