sukadev@xxxxxxxxxx writes: > From: Cedric Le Goater <clg@xxxxxxxxxx> > Subject: [RFC][PATCH 6/6]: Enable unsharing pid namespace. > > Enable unsharing of pid namespace - i.e allow creating and using > a new pid namespace and attaching multiple struct pid_nrs per > process, one for each namespace. > > Signed-off-by: Cedric Le Goater <clg@xxxxxxxxxx> > Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx> > > --- > include/linux/sched.h | 1 + > kernel/fork.c | 22 ++++++++++++++++++---- > kernel/nsproxy.c | 5 ++++- > kernel/pid.c | 18 ++++++++++++++++++ > 4 files changed, 41 insertions(+), 5 deletions(-) > > Index: lx26-20-mm2b/kernel/pid.c > =================================================================== > --- lx26-20-mm2b.orig/kernel/pid.c 2007-03-09 14:56:53.000000000 -0800 > +++ lx26-20-mm2b/kernel/pid.c 2007-03-09 15:03:05.000000000 -0800 > @@ -546,6 +546,24 @@ void free_pid_ns(struct kref *kref) > struct pid_namespace *ns; > > ns = container_of(kref, struct pid_namespace, kref); > + > + if (ns != &init_pid_ns) { A cleaned up version of this would make sense. We don't need to test that ns != init_pid_ns. Maybe BUG_ON(ns == &init_pid_ns); Or do you foresee freeing the initial pid namespace? > + /* BEGIN: to be removed soon */ > + int i; > + int nr_free = atomic_read(&ns->pidmap[0].nr_free); > + > + BUG_ON( nr_free != (BITS_PER_PAGE - 1)); > + > + if (unlikely(PIDMAP_ENTRIES != 1)) { > + for (i = 1; i < PIDMAP_ENTRIES; i++) { > + nr_free = atomic_read(&ns->pidmap[i].nr_free); > + BUG_ON(nr_free != BITS_PER_PAGE); > + } > + } What makes the first page in the pidmap special? None of the pages should have an allocated bit if we are freeing the pid namespace.... > + /* END: to be removed soon */ > + kfree(ns->pidmap[0].page); This is wrong. While a pid namespace is exists we don't free the page so you need to loop through all of the pidmap entries and free them. > + } > + > kfree(ns); > } > > Index: lx26-20-mm2b/include/linux/sched.h > =================================================================== > --- lx26-20-mm2b.orig/include/linux/sched.h 2007-03-09 14:56:12.000000000 -0800 > +++ lx26-20-mm2b/include/linux/sched.h 2007-03-09 14:56:53.000000000 -0800 > @@ -26,6 +26,7 @@ > #define CLONE_STOPPED 0x02000000 /* Start in stopped state */ > #define CLONE_NEWUTS 0x04000000 /* New utsname group? */ > #define CLONE_NEWIPC 0x08000000 /* New ipcs */ > +#define CLONE_NEWPID 0x10000000 /* New pid namespace */ Good. Although it may make sense to submit this as a separate patch. We should be able to reserve the number now. > Index: lx26-20-mm2b/kernel/fork.c > =================================================================== > --- lx26-20-mm2b.orig/kernel/fork.c 2007-03-09 14:56:12.000000000 -0800 > +++ lx26-20-mm2b/kernel/fork.c 2007-03-09 15:05:39.000000000 -0800 > @@ -57,6 +57,7 @@ > #include <asm/mmu_context.h> > #include <asm/cacheflush.h> > #include <asm/tlbflush.h> > +#include <linux/pid_namespace.h> I don't see do_fork support only unshare support which seems completely backwards to me. > @@ -1609,6 +1610,7 @@ asmlinkage long sys_unshare(unsigned lon > struct nsproxy *new_nsproxy = NULL, *old_nsproxy = NULL; > struct uts_namespace *uts, *new_uts = NULL; > struct ipc_namespace *ipc, *new_ipc = NULL; > + struct pid_nr *new_pid_nr = NULL; > > check_unshare_flags(&unshare_flags); > > @@ -1616,7 +1618,7 @@ asmlinkage long sys_unshare(unsigned lon > err = -EINVAL; > if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| > CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| > - CLONE_NEWUTS|CLONE_NEWIPC)) > + CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWPID)) > goto bad_unshare_out; > > if ((err = unshare_thread(unshare_flags))) > @@ -1637,18 +1639,20 @@ asmlinkage long sys_unshare(unsigned lon > goto bad_unshare_cleanup_semundo; > if ((err = unshare_ipcs(unshare_flags, &new_ipc))) > goto bad_unshare_cleanup_uts; > + if ((err = unshare_pid_ns(unshare_flags, &new_pid_nr))) > + goto bad_unshare_cleanup_ipc; > > - if (new_ns || new_uts || new_ipc) { > + if (new_ns || new_uts || new_ipc || new_pid_nr) { > old_nsproxy = current->nsproxy; > new_nsproxy = dup_namespaces(old_nsproxy); > if (!new_nsproxy) { > err = -ENOMEM; > - goto bad_unshare_cleanup_ipc; > + goto bad_unshare_cleanup_pid; > } > } > > if (new_fs || new_ns || new_mm || new_fd || new_ulist || > - new_uts || new_ipc) { > + new_uts || new_ipc || new_pid_nr) { > > task_lock(current); > > @@ -1696,12 +1700,22 @@ asmlinkage long sys_unshare(unsigned lon > new_ipc = ipc; > } > > + if (new_pid_nr) { > + pid = task_pid_ns(current); > + set_task_pid_ns(current, new_pid_nr->pid_ns); > + new_pid_nr = NULL; > + } > + > task_unlock(current); > } > > if (new_nsproxy) > put_nsproxy(new_nsproxy); > > +bad_unshare_cleanup_pid: > + if (new_pid_nr) > + free_pidmap_pid_nr(new_pid_nr); > + > bad_unshare_cleanup_ipc: > if (new_ipc) > put_ipc_ns(new_ipc); > Index: lx26-20-mm2b/kernel/nsproxy.c > =================================================================== > --- lx26-20-mm2b.orig/kernel/nsproxy.c 2007-03-09 14:56:12.000000000 -0800 > +++ lx26-20-mm2b/kernel/nsproxy.c 2007-03-09 15:03:05.000000000 -0800 > @@ -83,13 +83,16 @@ int copy_namespaces(int flags, struct ta > struct nsproxy *old_ns = tsk->nsproxy; > struct nsproxy *new_ns; > int err = 0; > + int ns_all; > > if (!old_ns) > return 0; > > get_nsproxy(old_ns); > > - if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC))) > + ns_all = CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWPID; > + This doesn't quite seem to make sense why the extra intermediate variable? > + if (!(flags & ns_all)) > return 0; > Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxx https://lists.osdl.org/mailman/listinfo/containers