[PATCH 00/10] uprobes: longjmp fixes

[Oleg Nesterov <oleg@redhat.com>]

Hello.

Currently ret-probes can't work (the application will likely crash)
if the probed function does not return, and this is even documented
in handle_trampoline().

This series tries to make the first step to fix the problem on x86:
it assumes that the probed functions use the same stack.

TODO: sigaltstack() can obviously break this assumption.

NOTE: I don't think it is possible to make this logic 100% correct,
the user-space can do everything with its stack. For example, the
application can do longjmp-like tricks to implement the coroutines,
the kernel can do nothing in this case. The application (or debugger)
should cooperate somehow to let the kernel know whats going on.

Jan, David, Pratyush, Ananth, do you think your architecure can reuse
the hacks/hooks added by this series and do something like x86 does?
If not, we will probably need "plan B" mentioned in 08/10, but I'd
like to avoid this if possible. Or any other thoughts?

Oleg.

 arch/arm/include/asm/uprobes.h     |    3 +
 arch/arm/probes/uprobes/core.c     |    3 +-
 arch/powerpc/include/asm/uprobes.h |    3 +
 arch/powerpc/kernel/uprobes.c      |    3 +-
 arch/s390/include/asm/uprobes.h    |    3 +
 arch/s390/kernel/uprobes.c         |    3 +-
 arch/x86/include/asm/uprobes.h     |    4 +
 arch/x86/kernel/uprobes.c          |   15 +++-
 include/linux/uprobes.h            |    5 +-
 kernel/events/uprobes.c            |  170 +++++++++++++++++++++---------------
 10 files changed, 136 insertions(+), 76 deletions(-)