Messages in this thread | | | From | Bernd Edlinger <> | Subject | Re: [PATCH v2 4/5] exec: Move exec_mmap right after de_thread in flush_old_exec | Date | Mon, 9 Mar 2020 19:52:38 +0000 |
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On 3/9/20 8:45 PM, Eric W. Biederman wrote: > Bernd Edlinger <bernd.edlinger@hotmail.de> 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@hotmail.de> > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> > > Eric >
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