On 09/12, Jürg Billeter wrote: > > On Tue, 2017-09-12 at 19:05 +0200, Oleg Nesterov wrote: > > On 09/09, Jürg Billeter wrote: > > > Unlike > > > PR_SET_PDEATHSIG, this is inherited across fork to allow killing a whole > > > subtree without race conditions. > > > > but I am still not sure this is right... at least I can't understand the > > "without race conditions" above. > > > > IOW, the child can do prctl(PR_SET_PDEATHSIG_PROC, SIGKILL) right after > > fork(), > > why this is not enough to kill a whole subtree without race conditions? > > What if the parent dies between fork() and prctl()?
The child will be killed? Sorry, can't understand... > it also makes it relatively easy to enforce > PDEATHSIG_PROC for all descendants of a process. this is clear, > > Say, CLONE_PARENT. Should it succeed if ->pdeath_signal_proc != 0 ? > > Yes, I don't see an issue with that. The new process will be a sibling > and inheriting pdeath_signal_proc seems sensible to me for this. I meant, the process created by clone(CLONE_PARENT) won't be killed by pdeath_signal if the creator process exits, exactly because it won't be its child. Not that I think this is wrong. Oleg.
