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| author | Puranjay Mohan <puranjay@kernel.org> | 2024-04-24 10:02:10 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-04-26 09:45:18 -0700 |
| commit | 7cd6750d9a560fa69bb640a7280479d6a67999ad (patch) | |
| tree | abcf803874950c1abaeacc544d3a317d2ff8d2fb | |
| parent | b599d7d26d6ad1fc9975218574bc2ca6d0293cfd (diff) | |
| download | net-7cd6750d9a560fa69bb640a7280479d6a67999ad.tar.gz | |
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>
| -rw-r--r-- | tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 3 |
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 39ad96a18123f6..edcd26106557b4 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; } } |