Josh Kunz <j...@google.com> writes:
> This patch series implements extended support for the `clone` system > call. As best I can tell, any option combination including `CLONE_VM` > should be supported with the addition of this patch series. The > implementation is described in greater detail in the patches themselves. > > Testing: > > * All targets built on x86_64. > * `make check` and `make check-tcg` are passing. Additional tests have > been added to `linux-test.c` to validate clone behavior. > > Caveats: > > * This series touches, but does not fix, several bits of code that are > racey (namely the sigact table and the fd trans table). > * `exit_group` does not perform the appropriate cleanup for non-thread > children created with `CLONE_VM`. CPUs for such children are never > cleaned up. The correct implementation of exit-group is non-trivial > (since it also needs to track/handle cleanup for threads in the > clone'd child process). Also, I don't fully understand the > interaction between QOM<->linux-user. When the QOM object gets unrefed for the final time it should cause a bunch of clean-up in the common vCPU management code where things like plugin cleanup are done. This was recently touched in 1f81ce90e31ef338ee53a0cea02344237bc470cc where I removed linux-user messing around with the active cpu list and left it to the core code to deal with. Previously it wasn't being properly unrealized. > My naive implementation based > on the current implementation `exit(2)` was regularly crashing. If > maintainers have suggestions for better ways to handle exit_group, > they would be greatly appreciated. > * execve does not clean up the CPUs of clone'd children, for the same > reasons as `exit_group`. > > Josh Kunz (5): > linux-user: Refactor do_fork to use new `qemu_clone` > linux-user: Make fd_trans task-specific. > linux-user: Make sigact_table part of the task state. > linux-user: Support CLONE_VM and extended clone options > linux-user: Add PDEATHSIG test for clone process hierarchy. > > linux-user/Makefile.objs | 2 +- > linux-user/clone.c | 565 ++++++++++++++++++++++++++++ > linux-user/clone.h | 27 ++ > linux-user/fd-trans-tbl.c | 13 + > linux-user/fd-trans-type.h | 17 + > linux-user/fd-trans.c | 3 - > linux-user/fd-trans.h | 75 ++-- > linux-user/main.c | 1 + > linux-user/qemu.h | 49 +++ > linux-user/signal.c | 84 ++++- > linux-user/syscall.c | 452 ++++++++++++---------- > tests/tcg/multiarch/Makefile.target | 3 + > tests/tcg/multiarch/linux-test.c | 227 ++++++++++- > 13 files changed, 1264 insertions(+), 254 deletions(-) > create mode 100644 linux-user/clone.c > create mode 100644 linux-user/clone.h > create mode 100644 linux-user/fd-trans-tbl.c > create mode 100644 linux-user/fd-trans-type.h -- Alex Bennée