From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: laurent@vivier.eu, richard.purdie@linuxfoundation.org,
mjt@tls.msk.ru, iii@linux.ibm.com
Subject: [PATCH v2 5/5] tests/tcg: Check that shmat() does not break /proc/self/maps
Date: Wed, 28 Feb 2024 10:25:18 -1000 [thread overview]
Message-ID: <20240228202518.33180-6-richard.henderson@linaro.org> (raw)
In-Reply-To: <20240228202518.33180-1-richard.henderson@linaro.org>
From: Ilya Leoshkevich <iii@linux.ibm.com>
Add a regression test for a recently fixed issue, where shmat()
desynced the guest and the host view of the address space and caused
open("/proc/self/maps") to SEGV.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <jwyuvao4apydvykmsnvacwshdgy3ixv7qvkh4dbxm3jkwgnttw@k4wpaayou7oq>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
tests/tcg/multiarch/linux/linux-shmat-maps.c | 55 ++++++++++++++++++++
1 file changed, 55 insertions(+)
create mode 100644 tests/tcg/multiarch/linux/linux-shmat-maps.c
diff --git a/tests/tcg/multiarch/linux/linux-shmat-maps.c b/tests/tcg/multiarch/linux/linux-shmat-maps.c
new file mode 100644
index 0000000000..0ccf7a973a
--- /dev/null
+++ b/tests/tcg/multiarch/linux/linux-shmat-maps.c
@@ -0,0 +1,55 @@
+/*
+ * Test that shmat() does not break /proc/self/maps.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include <assert.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <unistd.h>
+
+int main(void)
+{
+ char buf[128];
+ int err, fd;
+ int shmid;
+ ssize_t n;
+ void *p;
+
+ shmid = shmget(IPC_PRIVATE, 1, IPC_CREAT | 0600);
+ assert(shmid != -1);
+
+ /*
+ * The original bug required a non-NULL address, which skipped the
+ * mmap_find_vma step, which could result in a host mapping smaller
+ * than the target mapping. Choose an address at random.
+ */
+ p = shmat(shmid, (void *)0x800000, SHM_RND);
+ if (p == (void *)-1) {
+ /*
+ * Because we are now running the testcase for all guests for which
+ * we have a cross-compiler, the above random address might conflict
+ * with the guest executable in some way. Rather than stopping,
+ * continue with a system supplied address, which should never fail.
+ */
+ p = shmat(shmid, NULL, 0);
+ assert(p != (void *)-1);
+ }
+
+ fd = open("/proc/self/maps", O_RDONLY);
+ assert(fd != -1);
+ do {
+ n = read(fd, buf, sizeof(buf));
+ assert(n >= 0);
+ } while (n != 0);
+ close(fd);
+
+ err = shmdt(p);
+ assert(err == 0);
+ err = shmctl(shmid, IPC_RMID, NULL);
+ assert(err == 0);
+
+ return EXIT_SUCCESS;
+}
--
2.34.1
next prev parent reply other threads:[~2024-02-28 20:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-28 20:25 [PATCH v2 0/5] linux-user: Rewrite target_shmat Richard Henderson
2024-02-28 20:25 ` [PATCH v2 1/5] linux-user/x86_64: Handle the vsyscall page in open_self_maps_{2, 4} Richard Henderson
2024-02-29 9:48 ` Philippe Mathieu-Daudé
2024-02-28 20:25 ` [PATCH v2 2/5] linux-user/loongarch64: Remove TARGET_FORCE_SHMLBA Richard Henderson
2024-02-28 20:25 ` [PATCH v2 3/5] linux-user: Add strace for shmat Richard Henderson
2024-03-01 13:34 ` Philippe Mathieu-Daudé
2024-02-28 20:25 ` [PATCH v2 4/5] linux-user: Rewrite target_shmat Richard Henderson
2024-02-28 20:25 ` Richard Henderson [this message]
2024-02-29 12:27 ` [PATCH v2 0/5] " Richard Purdie
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