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authorPuranjay Mohan <puranjay@kernel.org>2024-04-24 13:02:10 +0300
committerAlexei Starovoitov <ast@kernel.org>2024-04-26 19:45:18 +0300
commit7cd6750d9a560fa69bb640a7280479d6a67999ad (patch)
treeabcf803874950c1abaeacc544d3a317d2ff8d2fb /tools
parentb599d7d26d6ad1fc9975218574bc2ca6d0293cfd (diff)
downloadlinux-7cd6750d9a560fa69bb640a7280479d6a67999ad.tar.xz
selftests/bpf: Test PROBE_MEM of VSYSCALL_ADDR on x86-64
The vsyscall is a legacy API for fast execution of system calls. It maps a page at address VSYSCALL_ADDR into the userspace program. This address is in the top 10MB of the address space: ffffffffff600000 - ffffffffff600fff | 4 kB | legacy vsyscall ABI The last commit fixes the x86-64 BPF JIT to skip accessing addresses in this memory region. Add this address to bpf_testmod_return_ptr() so we can make sure that it is fixed. After this change and without the previous commit, subprogs_extable selftest will crash the kernel. Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Link: https://lore.kernel.org/r/20240424100210.11982-4-puranjay@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 39ad96a18123..edcd26106557 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -205,6 +205,9 @@ __weak noinline struct file *bpf_testmod_return_ptr(int arg)
case 5: return (void *)~(1ull << 30); /* trigger extable */
case 6: return &f; /* valid addr */
case 7: return (void *)((long)&f | 1); /* kernel tricks */
+#ifdef CONFIG_X86_64
+ case 8: return (void *)VSYSCALL_ADDR; /* vsyscall page address */
+#endif
default: return NULL;
}
}