On Thu, Jan 26, 2023 at 01:30:08AM +0100, Oleg Nesterov wrote: > On 01/24, Gregory Price wrote: > > > > Adds PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH to ptrace options, and > > modify Syscall User Dispatch to suspend interception when enabled. > > > > This is modeled after the SUSPEND_SECCOMP feature, which suspends > > SECCOMP interposition. Without doing this, software like CRIU will > > inject system calls into a process and be intercepted by Syscall > > User Dispatch, either causing a crash (due to blocked signals) or > > the delivery of those signals to a ptracer (not the intended behavior). > > Cough... Gregory, I am sorry ;) > > but can't we drop this patch to ? > > CRIU needs to do PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG and check > config->mode anyway as we discussed. > > Then it can simply set *config->selector = SYSCALL_DISPATCH_FILTER_ALLOW > with the same effect, no? > > Oleg. > After further investigation, I believe we can drop 1/2, but for a different reason: It's actually insane behavior during the quiesce phase. Quiesce allows the program to run until a particular state, which means we can't turn it off lest we interfere with intended behavior - (cough cough prior review said this cough cough i'm dumb). I'll drop patch 1/2 and resubmit (there's an unused variable warning i need to clean up). Thanks again for the reviews all ~Gregory
