From d69cba5c719b0c551f6380ec5da4ed8c20a3815a Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 15 Aug 2021 23:29:15 +0200
Subject: [PATCH] futex: Reorder sanity checks in futex_requeue()
Git-commit: d69cba5c719b0c551f6380ec5da4ed8c20a3815a
Patch-mainline: v5.15-rc1
References: bsc#1190137 bsc#1189998
No point in allocating memory when the input parameters are bogus.
Validate all parameters before proceeding.
Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.581789253@linutronix.de
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
kernel/futex.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 8d8bad5e07bb..a5232f62de75 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1933,13 +1933,6 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
if (uaddr1 == uaddr2)
return -EINVAL;
- /*
- * requeue_pi requires a pi_state, try to allocate it now
- * without any locks in case it fails.
- */
- if (refill_pi_state_cache())
- return -ENOMEM;
-
/*
* futex_requeue() allows the caller to define the number
* of waiters to wake up via the @nr_wake argument. With
@@ -1963,6 +1956,13 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
*/
if (nr_wake != 1)
return -EINVAL;
+
+ /*
+ * requeue_pi requires a pi_state, try to allocate it now
+ * without any locks in case it fails.
+ */
+ if (refill_pi_state_cache())
+ return -ENOMEM;
}
retry:
--
2.26.2