kernel/linux.git/tools/testing/selftests/x86, branch v6.12.80

selftests/x86: Add a test to detect infinite SIGTRAP handler loop

2025-06-27T10:11:38+00:00

commit f287822688eeb44ae1cf6ac45701d965efc33218 upstream. When FRED is enabled, if the Trap Flag (TF) is set without an external debugger attached, it can lead to an infinite loop in the SIGTRAP handler. To avoid this, the software event flag in the augmented SS must be cleared, ensuring that no single-step trap remains pending when ERETU completes. This test checks for that specific scenario—verifying whether the kernel correctly prevents an infinite SIGTRAP loop in this edge case when FRED is enabled. The test should _always_ pass with IDT event delivery, thus no need to disable the test even when FRED is not enabled. Signed-off-by: Xin Li (Intel) Signed-off-by: Dave Hansen Tested-by: Sohil Mehta Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250609084054.2083189-3-xin%40zytor.com Signed-off-by: Greg Kroah-Hartman

selftest/x86/bugs: Add selftests for ITS

2025-05-18T06:24:59+00:00

commit 7a9b709e7cc5ce1ffb84ce07bf6d157e1de758df upstream. Below are the tests added for Indirect Target Selection (ITS): - its_sysfs.py - Check if sysfs reflects the correct mitigation status for the mitigation selected via the kernel cmdline. - its_permutations.py - tests mitigation selection with cmdline permutations with other bugs like spectre_v2 and retbleed. - its_indirect_alignment.py - verifies that for addresses in .retpoline_sites section that belong to lower half of cacheline are patched to ITS-safe thunk. Typical output looks like below: Site 49: function symbol: __x64_sys_restart_syscall+0x1f <0xffffffffbb1509af> # vmlinux: 0xffffffff813509af: jmp 0xffffffff81f5a8e0 # kcore: 0xffffffffbb1509af: jmpq *%rax # ITS thunk NOT expected for site 49 # PASSED: Found *%rax # Site 50: function symbol: __resched_curr+0xb0 <0xffffffffbb181910> # vmlinux: 0xffffffff81381910: jmp 0xffffffff81f5a8e0 # kcore: 0xffffffffbb181910: jmp 0xffffffffc02000fc # ITS thunk expected for site 50 # PASSED: Found 0xffffffffc02000fc -> jmpq *%rax - its_ret_alignment.py - verifies that for addresses in .return_sites section that belong to lower half of cacheline are patched to its_return_thunk. Typical output looks like below: Site 97: function symbol: collect_event+0x48 <0xffffffffbb007f18> # vmlinux: 0xffffffff81207f18: jmp 0xffffffff81f5b500 # kcore: 0xffffffffbb007f18: jmp 0xffffffffbbd5b560 # PASSED: Found jmp 0xffffffffbbd5b560 # Site 98: function symbol: collect_event+0xa4 <0xffffffffbb007f74> # vmlinux: 0xffffffff81207f74: jmp 0xffffffff81f5b500 # kcore: 0xffffffffbb007f74: retq # PASSED: Found retq Some of these tests have dependency on tools like virtme-ng[1] and drgn[2]. When the dependencies are not met, the test will be skipped. [1] https://github.com/arighi/virtme-ng [2] https://github.com/osandov/drgn Co-developed-by: Tao Zhang Signed-off-by: Tao Zhang Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Signed-off-by: Greg Kroah-Hartman

Documentation/srso: Document a method for checking safe RET operates properly

2024-08-27T07:16:35+00:00

Add a method to quickly verify whether safe RET operates properly on a given system using perf tool. Also, add a selftest which does the same thing. Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240731160531.28640-1-bp@kernel.org

Merge tag 'probes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2024-07-18T19:19:20+00:00

Pull probes updates from Masami Hiramatsu: "Uprobes: - x86/shstk: Make return uprobe work with shadow stack - Add uretprobe syscall which speeds up the uretprobe 10-30% faster. This syscall is automatically used from user-space trampolines which are generated by the uretprobe. If this syscall is used by normal user program, it will cause SIGILL. Note that this is currently only implemented on x86_64. (This also has two fixes for adjusting the syscall number to avoid conflict with new *attrat syscalls.) - uprobes/perf: fix user stack traces in the presence of pending uretprobe. This corrects the uretprobe's trampoline address in the stacktrace with correct return address - selftests/x86: Add a return uprobe with shadow stack test - selftests/bpf: Add uretprobe syscall related tests. - test case for register integrity check - test case with register changing case - test case for uretprobe syscall without uprobes (expected to fail) - test case for uretprobe with shadow stack - selftests/bpf: add test validating uprobe/uretprobe stack traces - MAINTAINERS: Add uprobes entry. This does not specify the tree but to clarify who maintains and reviews the uprobes Kprobes: - tracing/kprobes: Test case cleanups. Replace redundant WARN_ON_ONCE() + pr_warn() with WARN_ONCE() and remove unnecessary code from selftest - tracing/kprobes: Add symbol counting check when module loads. This checks the uniqueness of the probed symbol on modules. The same check has already done for kernel symbols (This also has a fix for build error with CONFIG_MODULES=n) Cleanup: - Add MODULE_DESCRIPTION() macros for fprobe and kprobe examples" * tag 'probes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: MAINTAINERS: Add uprobes entry selftests/bpf: Change uretprobe syscall number in uprobe_syscall test uprobe: Change uretprobe syscall scope and number tracing/kprobes: Fix build error when find_module() is not available tracing/kprobes: Add symbol counting check when module loads selftests/bpf: add test validating uprobe/uretprobe stack traces perf,uprobes: fix user stack traces in the presence of pending uretprobes tracing/kprobe: Remove cleanup code unrelated to selftest tracing/kprobe: Integrate test warnings into WARN_ONCE selftests/bpf: Add uretprobe shadow stack test selftests/bpf: Add uretprobe syscall call from user space test selftests/bpf: Add uretprobe syscall test for regs changes selftests/bpf: Add uretprobe syscall test for regs integrity selftests/x86: Add return uprobe shadow stack test uprobe: Add uretprobe syscall to speed up return probe uprobe: Wire up uretprobe system call x86/shstk: Make return uprobe work with shadow stack samples: kprobes: add missing MODULE_DESCRIPTION() macros fprobe: add missing MODULE_DESCRIPTION() macro

selftests/x86: fix printk warnings reported by clang

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

These warnings are all of the form, "the format specified a short (signed or unsigned) int, but the value is a full length int". Acked-by: Muhammad Usama Anjum Signed-off-by: John Hubbard Signed-off-by: Shuah Khan

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: avoid -no-pie warnings from clang during compilation

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

When building with clang, via: make LLVM=1 -C tools/testing/selftests ...clang warns that -no-pie is "unused during compilation". This occurs because clang only wants to see -no-pie during linking. Here, we don't have a separate linking stage, so a compiler warning is unavoidable without (wastefully) restructuring the Makefile. Avoid the warning by simply disabling that warning, for clang builds. Acked-by: Muhammad Usama Anjum Signed-off-by: John Hubbard Signed-off-by: Shuah Khan

selftests/x86: build sysret_rip.c with clang

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

When building with clang, via: make LLVM=1 -C tools/testing/selftests ...the build fails because clang's inline asm doesn't support all of the features that are used in the asm() snippet in sysret_rip.c. Fix this by moving the asm code into the clang_helpers_64.S file, where it can be built with the assembler's full set of features. Acked-by: Muhammad Usama Anjum Signed-off-by: John Hubbard Signed-off-by: Shuah Khan

selftests/x86: build fsgsbase_restore.c with clang

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

When building with clang, via: make LLVM=1 -C tools/testing/selftests Fix this by moving the inline asm to "pure" assembly, in two new files: clang_helpers_32.S, clang_helpers_64.S. As a bonus, the pure asm avoids the need for ifdefs, and is now very simple and easy on the eyes. Acked-by: Muhammad Usama Anjum Signed-off-by: John Hubbard Signed-off-by: Shuah Khan

selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp

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

Use fisttps instead of fisttp to specify correctly that the output variable is of size short. test_FISTTP.c:28:3: error: ambiguous instructions require an explicit suffix (could be 'fisttps', or 'fisttpl') 28 | " fisttp res16""\n" | ^ :3:2: note: instantiated into assembly here 3 | fisttp res16 | ^ ...followed by three more cases of the same warning for other lines. [jh: removed a bit of duplication from the warnings report, above, and fixed a typo in the title] Signed-off-by: Muhammad Usama Anjum Signed-off-by: John Hubbard Signed-off-by: Shuah Khan