From: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
To: bpf@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org, andrii@kernel.org,
daniel@iogearbox.net, ast@kernel.org, cascardo@canonical.com
Subject: [PATCH] selftests/bpf: only munmap the mmaped ringbuf pages
Date: Thu, 13 May 2021 22:23:06 -0300 [thread overview]
Message-ID: <20210514012306.39020-1-cascardo@canonical.com> (raw)
One the mmap tests will map a single page, then try to extend the
mapping by use of mremap, which should fail. Right after that, it unmaps
the extended area, which may end up unmapping other valid mapped areas,
this causing a segfault.
Only unmap the area that is expected to be mapped.
Fixes: b2fb299c9aa4 ("selftests/bpf: test ringbuf mmap read-only and read-write restrictions")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
tools/testing/selftests/bpf/prog_tests/ringbuf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index 197e30b83298..f9a8ae331963 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -146,7 +146,7 @@ void test_ringbuf(void)
ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_protect");
ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_protect");
ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 3 * page_size, MREMAP_MAYMOVE), "ro_remap");
- ASSERT_OK(munmap(mmap_ptr, 3 * page_size), "unmap_ro");
+ ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro");
/* only trigger BPF program for current process */
skel->bss->pid = getpid();
--
2.30.2
next reply other threads:[~2021-05-14 1:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 1:23 Thadeu Lima de Souza Cascardo [this message]
2021-05-14 18:07 ` [PATCH] selftests/bpf: only munmap the mmaped ringbuf pages Andrii Nakryiko
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