[v9][PATCH 2/9] Have alloc_pidmap() return actual error code
From: Sukadev Bhattiprolu <hidden>
Date: 2009-10-25 03:37:50
Subsystem:
exec & binfmt api, elf, memory management - core, scheduler, the rest · Maintainers:
Kees Cook, Andrew Morton, David Hildenbrand, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
Subject: [v9][PATCH 2/9] Have alloc_pidmap() return actual error code alloc_pidmap() can fail either because all pid numbers are in use or because memory allocation failed. With support for setting a specific pid number, alloc_pidmap() would also fail if either the given pid number is invalid or in use. Rather than have callers assume -ENOMEM, have alloc_pidmap() return the actual error. Signed-off-by: Sukadev Bhattiprolu <redacted> Acked-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> Reviewed-by: Oren Laadan <redacted> --- kernel/fork.c | 5 +++-- kernel/pid.c | 14 +++++++++----- 2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 4c20fff..93626b2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -1156,10 +1156,11 @@ static struct task_struct *copy_process(unsigned long clone_flags, goto bad_fork_cleanup_io; if (pid != &init_struct_pid) { - retval = -ENOMEM; pid = alloc_pid(p->nsproxy->pid_ns); - if (!pid) + if (IS_ERR(pid)) { + retval = PTR_ERR(pid); goto bad_fork_cleanup_io; + } if (clone_flags & CLONE_NEWPID) { retval = pid_ns_prepare_proc(p->nsproxy->pid_ns);
diff --git a/kernel/pid.c b/kernel/pid.c
index 7d4bb6e..c4d9914 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c@@ -150,7 +150,7 @@ static int alloc_pidmap_page(struct pidmap *map) static int alloc_pidmap(struct pid_namespace *pid_ns) { int i, offset, max_scan, pid, last = pid_ns->last_pid; - int rc; + int rc = -EAGAIN; struct pidmap *map; pid = last + 1;
@@ -189,12 +189,14 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) } else { map = &pid_ns->pidmap[0]; offset = RESERVED_PIDS; - if (unlikely(last == offset)) + if (unlikely(last == offset)) { + rc = -EAGAIN; break; + } } pid = mk_pid(pid_ns, map, offset); } - return -1; + return rc; } int next_pidmap(struct pid_namespace *pid_ns, int last)
@@ -263,8 +265,10 @@ struct pid *alloc_pid(struct pid_namespace *ns) struct upid *upid; pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL); - if (!pid) + if (!pid) { + pid = ERR_PTR(-ENOMEM); goto out; + } tmp = ns; for (i = ns->level; i >= 0; i--) {
@@ -299,7 +303,7 @@ out_free: free_pidmap(pid->numbers + i); kmem_cache_free(ns->pid_cachep, pid); - pid = NULL; + pid = ERR_PTR(nr); goto out; }
--