https://pagure.io/libaio/pull-request/23

From f68c69b6cbc1260a6034997d5f146e3d0a197ed8 Mon Sep 17 00:00:00 2001
From: Xiongchuan Tan <xc-tan@outlook.com>
Date: Jun 28 2022 15:53:38 +0000
Subject: As of June 28th, 2022, the RISC-V spec[1] reserves the PTE permission bit

combination of "write+!read", and the kernel would have incoherent behavior in
the last test case of "harness/cases/5.t". Since it leads to undefined behavior,
until further spec update, this test case should be disabled for RISC-V.

A patch to disallow such permission in mmap() can be found here[2].

[1]: https://github.com/riscv/riscv-isa-manual/releases/download/Priv-v1.12/riscv-privileged-20211203.pdf
[2]: https://www.spinics.net/lists/kernel/msg4412421.html

---

diff --git a/harness/cases/5.t b/harness/cases/5.t
index b0a7c56..8d6c959 100644
--- a/harness/cases/5.t
+++ b/harness/cases/5.t
@@ -37,6 +37,14 @@ int test_main(void)
 	status |= attempt_rw(rwfd, buf, SIZE,  0,  READ, -EFAULT);
 
 	res = munmap(buf, page_size);			assert(res == 0);
+
+	/* As of  June 28th, 2022,  the RISC-V spec Volume 2 Section 4.3
+	 * version "20211203 Privileged Architecture v1.12, Ratified"
+	 * reserves the usage of  the PTE permission bit combination  of
+	 * "write+!read",   so the next test leads to undefined behavior
+	 * and should be disabled. */
+#ifndef __riscv
+
 	buf = mmap(0, page_size, PROT_WRITE, MAP_SHARED, rwfd, 0);
 	assert(buf != (char *)-1);
 
@@ -48,6 +56,8 @@ int test_main(void)
 	status |= attempt_rw(rwfd, buf, SIZE,  0,  READ, SIZE);
 	status |= attempt_rw(rwfd, buf, SIZE,  0, WRITE, res);
 
+#endif
+
 	return status;
 }
 

