linux.git/tools/testing/selftests/x86/fsgsbase.c, branch vsnprintf

selftests/x86: remove (or use) unused variables and functions

2024-07-11T17:23:55+00:00

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

...quite a few functions are variables are generating "unused" warnings.
Fix the warnings by deleting the unused items.

One item, the "nerrs" variable in vsdo_restorer.c's main(), is unused
but probably wants to be returned from main(), as a non-zero result.
That result is also unused right now, so another option would be to
delete it entirely, but this way, main() also gets fixed. It was missing
a return value.

Acked-by: Muhammad Usama Anjum 
Signed-off-by: John Hubbard 
Signed-off-by: Shuah Khan

selftests/x86/fsgsbase: Fix GS == 1, 2, and 3 tests

2020-11-24T12:46:16+00:00

Setting GS to 1, 2, or 3 causes a nonsensical part of the IRET microcode
to change GS back to zero on a return from kernel mode to user mode. The
result is that these tests fail randomly depending on when interrupts
happen. Detect when this happens and let the test pass.

Signed-off-by: Andy Lutomirski 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/7567fd44a1d60a9424f25b19a998f12149993b0d.1604346596.git.luto@kernel.org

selftests/x86/fsgsbase: Test PTRACE_PEEKUSER for GSBASE with invalid LDT GS

2020-08-26T18:54:18+00:00

This tests commit:

  8ab49526b53d ("x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task")

Unpatched kernels will OOPS.

Signed-off-by: Andy Lutomirski 
Signed-off-by: Ingo Molnar 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/c618ae86d1f757e01b1a8e79869f553cb88acf9a.1598461151.git.luto@kernel.org

selftests/x86/fsgsbase: Reap a forgotten child

2020-08-26T18:54:17+00:00

The ptrace() test forgot to reap its child.  Reap it.

Signed-off-by: Andy Lutomirski 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/e7700a503f30e79ab35a63103938a19893dbeff2.1598461151.git.luto@kernel.org

selftests/x86/fsgsbase: Add a missing memory constraint

2020-07-01T13:27:20+00:00

The manual call to set_thread_area() via int $0x80 was missing any
indication that the descriptor was a pointer, causing gcc to
occasionally generate wrong code.  Add the missing constraint.

Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Link: https://lkml.kernel.org/r/432968af67259ca92d68b774a731aff468eae610.1593192140.git.luto@kernel.org

selftests/x86/fsgsbase: Fix a comment in the ptrace_write_gsbase test

2020-07-01T13:27:20+00:00

A comment was unclear.  Fix it.

Fixes: 5e7ec8578fa3 ("selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE")
Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Link: https://lkml.kernel.org/r/901034a91a40169ec84f1f699ea86704dff762e4.1593192140.git.luto@kernel.org

selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE

2020-06-18T13:47:07+00:00

This validates that GS selector and base are independently preserved in
ptrace commands.

Suggested-by: Andy Lutomirski 
Signed-off-by: Chang S. Bae 
Signed-off-by: Sasha Levin 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Tony Luck 
Link: https://lkml.kernel.org/r/20200528201402.1708239-17-sashal@kernel.org

selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write

2020-06-18T13:47:06+00:00

The test validates that the selector is not changed when a ptracer writes
the ptracee's GS base.

Originally-by: Andy Lutomirski 
Signed-off-by: Chang S. Bae 
Signed-off-by: Sasha Levin 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Tony Luck 
Link: https://lkml.kernel.org/r/20200528201402.1708239-16-sashal@kernel.org

Revert "x86/ptrace: Prevent ptrace from clearing the FS/GS selector" and fix the test

2019-07-15T15:12:31+00:00

This reverts commit 48f5e52e916b55fb73754833efbacc7f8081a159.

The ptrace ABI change was a prerequisite to the proposed design for
FSGSBASE.  Since FSGSBASE support has been reverted, and since I'm not
convinced that the ABI was ever adequately tested, revert the ABI change as
well.

This also modifies the test case so that it tests the preexisting behavior.

Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Link: https://lkml.kernel.org/r/fca39c478ea7fb15bc76fe8a36bd180810a067f6.1563200250.git.luto@kernel.org

selftests/x86/fsgsbase: Fix some test case bugs

2019-07-03T14:24:56+00:00

This refactors do_unexpected_base() to clean up some code.  It also
fixes the following bugs in test_ptrace_write_gsbase():

 - Incorrect printf() format string caused crashes.

 - Hardcoded 0x7 for the gs selector was not reliably correct.

It also documents the fact that the test is expected to fail on old
kernels.

Fixes: a87730cc3acc ("selftests/x86/fsgsbase: Test ptracer-induced GSBASE write with FSGSBASE")
Fixes: 1b6858d5a2eb ("selftests/x86/fsgsbase: Test ptracer-induced GSBASE write")
Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Cc:  "BaeChang Seok" 
Cc: Borislav Petkov 
Cc: Peter Zijlstra 
Cc: "H . Peter Anvin" 
Cc: Andi Kleen 
Cc: H. Peter Anvin 
Cc: "BaeChang Seok" 
Link: https://lkml.kernel.org/r/bab29c84f2475e2c30ddb00f1b877fcd7f4f96a8.1562125333.git.luto@kernel.org