Oleg Nesterov <oleg@xxxxxxxxxx> writes: > On 05/05, Eric W. Biederman wrote: >> >> Eric W. Biederman (11): signal: Rename send_signal send_signal_locked >> signal: Replace __group_send_sig_info with send_signal_locked >> ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP ptrace/xtensa: >> Replace PT_SINGLESTEP with TIF_SINGLESTEP ptrace: Remove >> arch_ptrace_attach signal: Use lockdep_assert_held instead of >> assert_spin_locked ptrace: Reimplement PTRACE_KILL by always sending >> SIGKILL ptrace: Document that wait_task_inactive can't fail ptrace: >> Admit ptrace_stop can generate spuriuos SIGTRAPs ptrace: Don't change >> __state ptrace: Always take siglock in ptrace_resume >> >> Peter Zijlstra (1): >> sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state > > I can't comment 5/12. to be honest I didn't even try to look into > arch/ia64/. I just looked at arch_ptrace_attach again and I spotted what looks like a fairly easy analysis that is mostly arch-generic code that shows this is dead code on ia64. On ia64 arch_ptrace_attach is ptrace_attach_sync_user_rbs, and does nothing if __state is not TASK_STOPPED. When arch_ptrace_attach is called after ptrace_traceme __state is TASK_RUNNING pretty much by definition as we are running in the child. Therefore ptrace_attach_sync_user_rbs does nothing in that case. When arch_ptrace_attach is called after ptrace_attach __state there are two possibilities. If the tracee was already in TASK_STOPPED before the ptrace_attach, the tracee will be in TASK_TRACED. Otherwise the tracee will be in TASK_TRACED or on it's way to stopping in TASK_TRACED. Unless I totally misread ptrace_attach. There is no way that after a successful ptrace_attach for the tracee to be in TASK_STOPPED. This makes ptrace_attach_sync_user_rbs a big noop, AKA dead code. So it can be removed. > But other than that I see no problems in this version. However, I'd > like to actually apply the whole series and read the changed code > carefully, but sorry, I don't think I can do this before Monday. No rush. I don't expect the merge window will open for a while yet. Eric
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