Messages in this thread | | | Date | Tue, 10 Mar 2020 20:15:02 +0100 | From | Christian Brauner <> | Subject | Re: [PATCH] pidfd: Stop taking cred_guard_mutex |
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On Tue, Mar 10, 2020 at 01:52:05PM -0500, Eric W. Biederman wrote: > > During exec some file descriptors are closed and the files struct is > unshared. But all of that can happen at other times and it has the > same protections during exec as at ordinary times. So stop taking the > cred_guard_mutex as it is useless. > > Furthermore he cred_guard_mutex is a bad idea because it is deadlock > prone, as it is held in serveral while waiting possibly indefinitely > for userspace to do something. > > Cc: Sargun Dhillon <sargun@sargun.me> > Cc: Christian Brauner <christian.brauner@ubuntu.com> > Cc: Arnd Bergmann <arnd@arndb.de> > Fixes: 8649c322f75c ("pid: Implement pidfd_getfd syscall") > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> > --- > kernel/pid.c | 6 ------ > 1 file changed, 6 deletions(-) > > Christian if you don't have any objections I will take this one through > my tree.
Sure. Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
> > I tried to figure out why this code path takes the cred_guard_mutex and > the archive on lore.kernel.org was not helpful in finding that part of > the conversation.
Let me think a little harder and hopefully get back to you with a sensible explanation.
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