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Subject[PATCH] Fix failure path in alloc_pid()
Date
The failure path removes the allocated PIDs from the wrong namespace.
This could lead to us inadvertently reusing PIDs in the leaf namespace
and leaking PIDs in parent namespaces.

Fixes: 95846ecf9dac ("pid: replace pid bitmap implementation with IDR API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/pid.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/pid.c b/kernel/pid.c
index b2f6c506035da..20881598bdfac 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -233,8 +233,10 @@ struct pid *alloc_pid(struct pid_namespace *ns)

out_free:
spin_lock_irq(&pidmap_lock);
- while (++i <= ns->level)
- idr_remove(&ns->idr, (pid->numbers + i)->nr);
+ while (++i <= ns->level) {
+ upid = pid->numbers + i;
+ idr_remove(&upid->ns->idr, upid->nr);
+ }

/* On failure to allocate the first pid, reset the state */
if (ns->pid_allocated == PIDNS_ADDING)
--
2.19.2
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