On 3/9/20 8:45 PM, Eric W. Biederman wrote: > Bernd Edlinger <bernd.edlinger@xxxxxxxxxx> writes: > >> On 3/8/20 10:38 PM, Eric W. Biederman wrote: >>> >>> This consolidation allows the creation of a mutex to replace >>> cred_guard_mutex that is not held of possible indefinite userspace >> >> can you also reword this "held of" thing here as well? > > Done: > > exec: Move exec_mmap right after de_thread in flush_old_exec > > I have read through the code in exec_mmap and I do not see anything > that depends on sighand or the sighand lock, or on signals in anyway > so this should be safe. > > This rearrangement of code has two siginficant benefits. It makes watch out: sig_i_nificant > the determination of passing the point of no return by testing bprm->mm > accurate. All failures prior to that point in flush_old_exec are > either truly recoverable or they are fatal. > > Futher this consolidates all of the possible indefinite waits for Add some r to "Futher", please? > userspace together at the top of flush_old_exec. The possible wait > for a ptracer on PTRACE_EVENT_EXIT, the possible wait for a page fault > to be resolved in clear_child_tid, and the possible wait for a page > fault in exit_robust_list. > > This consolidation allows the creation of a mutex to replace > cred_guard_mutex that is not held over possible indefinite userspace > waits. Which will allow removing deadlock scenarios from the kernel. > > Reviewed-by: Bernd Edlinger <bernd.edlinger@xxxxxxxxxx> > Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > Eric >
