[PATCH 5/7] uprobes: Fix utask->xol_vaddr leak in pre_ssout()

[Oleg Nesterov <oleg@redhat.com>]

pre_ssout() should do xol_free_insn_slot() if arch_uprobe_pre_xol()
fails, otherwise nobody will free the allocated slot.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 kernel/events/uprobes.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2ed6239..bd94d2c 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1306,6 +1306,7 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
 {
 	struct uprobe_task *utask;
 	unsigned long xol_vaddr;
+	int err;
 
 	utask = current->utask;
 
@@ -1316,7 +1317,13 @@ pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
 	utask->xol_vaddr = xol_vaddr;
 	utask->vaddr = bp_vaddr;
 
-	return arch_uprobe_pre_xol(&uprobe->arch, regs);
+	err = arch_uprobe_pre_xol(&uprobe->arch, regs);
+	if (unlikely(err)) {
+		xol_free_insn_slot(current);
+		return err;
+	}
+
+	return 0;
 }
 
 /*
-- 
1.5.5.1