diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-09-03 18:43:06 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-09-03 18:43:06 -0700 |
commit | 8381979dfa056dee4df83d1b98740b68776ae8ac (patch) | |
tree | 14cba0617b988a4933122639b9113500c0aac030 /tools/testing/selftests/x86 | |
parent | e28f0104343d0c132fa37f479870c9e43355fee4 (diff) | |
parent | 8891adc61dce2a8a41fc0c23262b681c3ec4b73a (diff) |
Merge branch 'gate-page-refcount' (patches from Dave Hansen)
Merge gate page refcount fix from Dave Hansen:
"During the conversion over to pin_user_pages(), gate pages were missed.
The fix is pretty simple, and is accompanied by a new test from Andy
which probably would have caught this earlier"
* emailed patches from Dave Hansen <dave.hansen@linux.intel.com>:
selftests/x86/test_vsyscall: Improve the process_vm_readv() test
mm: fix pin vs. gup mismatch with gate pages
Diffstat (limited to 'tools/testing/selftests/x86')
-rw-r--r-- | tools/testing/selftests/x86/test_vsyscall.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c index c41f24b517f4..65c141ebfbbd 100644 --- a/tools/testing/selftests/x86/test_vsyscall.c +++ b/tools/testing/selftests/x86/test_vsyscall.c @@ -462,6 +462,17 @@ static int test_vsys_x(void) return 0; } +/* + * Debuggers expect ptrace() to be able to peek at the vsyscall page. + * Use process_vm_readv() as a proxy for ptrace() to test this. We + * want it to work in the vsyscall=emulate case and to fail in the + * vsyscall=xonly case. + * + * It's worth noting that this ABI is a bit nutty. write(2) can't + * read from the vsyscall page on any kernel version or mode. The + * fact that ptrace() ever worked was a nice courtesy of old kernels, + * but the code to support it is fairly gross. + */ static int test_process_vm_readv(void) { #ifdef __x86_64__ @@ -477,8 +488,12 @@ static int test_process_vm_readv(void) remote.iov_len = 4096; ret = process_vm_readv(getpid(), &local, 1, &remote, 1, 0); if (ret != 4096) { - printf("[OK]\tprocess_vm_readv() failed (ret = %d, errno = %d)\n", ret, errno); - return 0; + /* + * We expect process_vm_readv() to work if and only if the + * vsyscall page is readable. + */ + printf("[%s]\tprocess_vm_readv() failed (ret = %d, errno = %d)\n", vsyscall_map_r ? "FAIL" : "OK", ret, errno); + return vsyscall_map_r ? 1 : 0; } if (vsyscall_map_r) { @@ -488,6 +503,9 @@ static int test_process_vm_readv(void) printf("[FAIL]\tIt worked but returned incorrect data\n"); return 1; } + } else { + printf("[FAIL]\tprocess_rm_readv() succeeded, but it should have failed in this configuration\n"); + return 1; } #endif |