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authorLinus Torvalds <torvalds@linux-foundation.org>2020-05-10 11:39:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-10 11:39:31 -0700
commitbd2049f87107906e4f8dc443ff307c44951d5768 (patch)
parent27d2dcb1b95c8c39da417839c11eda2e665cd389 (diff)
parent8101b5a1531f3390b3a69fa7934c70a8fd6566ad (diff)
Merge tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Thomas Gleixner: "A single fix for the fallout of the recent futex uacess rework. With those changes GCC9 fails to analyze arch_futex_atomic_op_inuser() correctly and emits a 'maybe unitialized' warning. While we usually ignore compiler stupidity the conditional store is pointless anyway because the correct case has to store. For the fault case the extra store does no harm" * tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ARM: futex: Address build warning
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h
index e133da303a98..a9151884bc85 100644
--- a/arch/arm/include/asm/futex.h
+++ b/arch/arm/include/asm/futex.h
@@ -165,8 +165,13 @@ arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
- if (!ret)
- *oval = oldval;
+ /*
+ * Store unconditionally. If ret != 0 the extra store is the least
+ * of the worries but GCC cannot figure out that __futex_atomic_op()
+ * is either setting ret to -EFAULT or storing the old value in
+ * oldval which results in a uninitialized warning at the call site.
+ */
+ *oval = oldval;
return ret;