From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 26 Nov 2020 20:29:01 +0000 (-0500)
Subject: Fix: counter: cast UINT*_MAX to 64-bit signed type before negative
X-Git-Url: http://git.efficios.com/?p=deliverable%2Flttng-ust.git;a=commitdiff_plain;h=a40716088ab08fa708b2b2ba5024c3c62eee8805

Fix: counter: cast UINT*_MAX to 64-bit signed type before negative

(long long)-UINT32_MAX leads to value 1 which is not what we expect.
This is due to implicit type promotion from unsigned to signed 32-bit
integer.

Apply this to 8-bit and 16-bit types as well even though they are
not affected by this issue to keep things regular.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I8e05f270eae71cb15848075c4dfae80e8070fd80
---

diff --git a/libcounter/counter-api.h b/libcounter/counter-api.h
index 0a7c0ade..d18fa16e 100644
--- a/libcounter/counter-api.h
+++ b/libcounter/counter-api.h
@@ -104,7 +104,7 @@ static inline int __lttng_counter_add(const struct lib_counter_config *config,
 		}
 		if (v > 0 && (v >= UINT8_MAX || n < old))
 			overflow = true;
-		else if (v < 0 && (v <= -UINT8_MAX || n > old))
+		else if (v < 0 && (v <= -(int64_t) UINT8_MAX || n > old))
 			underflow = true;
 		break;
 	}
@@ -143,7 +143,7 @@ static inline int __lttng_counter_add(const struct lib_counter_config *config,
 		}
 		if (v > 0 && (v >= UINT16_MAX || n < old))
 			overflow = true;
-		else if (v < 0 && (v <= -UINT16_MAX || n > old))
+		else if (v < 0 && (v <= -(int64_t) UINT16_MAX || n > old))
 			underflow = true;
 		break;
 	}
@@ -182,7 +182,7 @@ static inline int __lttng_counter_add(const struct lib_counter_config *config,
 		}
 		if (v > 0 && (v >= UINT32_MAX || n < old))
 			overflow = true;
-		else if (v < 0 && (v <= -UINT32_MAX || n > old))
+		else if (v < 0 && (v <= -(int64_t) UINT32_MAX || n > old))
 			underflow = true;
 		break;
 	}