From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 1ED151A0023 for ; Fri, 20 Nov 2015 15:15:42 +1100 (AEDT) From: Michael Neuling To: mpe@ellerman.id.au, benh@kernel.crashing.org Cc: mikey@neuling.org, sam.bobroff@au1.ibm.com, linuxppc-dev@ozlabs.org, paulus@samba.org Subject: [PATCH v2 3/3] selftests/powerpc: Add TM signal with invalid stack test Date: Fri, 20 Nov 2015 15:15:34 +1100 Message-Id: <1447992934-18905-4-git-send-email-mikey@neuling.org> In-Reply-To: <1447992934-18905-1-git-send-email-mikey@neuling.org> References: <1447992934-18905-1-git-send-email-mikey@neuling.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Test the kernels signal generation code to ensure it can handle an invalid stack pointer when transactional. Signed-off-by: Michael Neuling --- tools/testing/selftests/powerpc/tm/.gitignore | 1 + tools/testing/selftests/powerpc/tm/Makefile | 2 +- .../testing/selftests/powerpc/tm/tm-signal-stack.c | 73 ++++++++++++++++++++++ 3 files changed, 75 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/powerpc/tm/tm-signal-stack.c diff --git a/tools/testing/selftests/powerpc/tm/.gitignore b/tools/testing/selftests/powerpc/tm/.gitignore index 61c318f..e666821 100644 --- a/tools/testing/selftests/powerpc/tm/.gitignore +++ b/tools/testing/selftests/powerpc/tm/.gitignore @@ -1,3 +1,4 @@ tm-resched-dscr tm-syscall tm-signal-msr-resv +tm-signal-stack diff --git a/tools/testing/selftests/powerpc/tm/Makefile b/tools/testing/selftests/powerpc/tm/Makefile index 0c28db7..0e45c7e 100644 --- a/tools/testing/selftests/powerpc/tm/Makefile +++ b/tools/testing/selftests/powerpc/tm/Makefile @@ -1,4 +1,4 @@ -TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv +TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack all: $(TEST_PROGS) diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-stack.c b/tools/testing/selftests/powerpc/tm/tm-signal-stack.c new file mode 100644 index 0000000..62f2a5f --- /dev/null +++ b/tools/testing/selftests/powerpc/tm/tm-signal-stack.c @@ -0,0 +1,73 @@ +/* + * Copyright 2015, Michael Neuling, IBM Corp. + * Licensed under GPLv2. + * + * Test the kernel's signal delievery code to ensure that we don't + * trelaim twice in the kernel signal delivery code. This can happen + * if we trigger a signal when in a transaction and the stack pointer + * is bogus. + * + * This test case registers a SEGV handler, sets the stack pointer + * (r1) to NULL, starts a transaction and then generates a SEGV. The + * SEGV should be handled but we exit here as the stack pointer is + * invalid and hance we can't sigreturn. We only need to check that + * this flow doesn't crash the kernel. + */ + +#include +#include +#include +#include +#include +#include + +#include "utils.h" + +void signal_segv(int signum) +{ + /* This should never actually run since stack is foobar */ + exit(1); +} + +int tm_signal_stack() +{ + int pid; + + pid = fork(); + if (pid < 0) + exit(1); + + if (pid) { /* Parent */ + /* + * It's likely the whole machine will crash here so if + * the child ever exits, we are good. + */ + wait(NULL); + return 0; + } + + /* + * The flow here is: + * 1) register a signal handler (so signal delievery occurs) + * 2) make stack pointer (r1) = NULL + * 3) start transaction + * 4) cause segv + */ + if (signal(SIGSEGV, signal_segv) == SIG_ERR) + exit(1); + asm volatile("li 1, 0 ;" /* stack ptr == NULL */ + "1:" + ".long 0x7C00051D ;" /* tbegin */ + "beq 1b ;" /* retry forever */ + ".long 0x7C0005DD ; ;" /* tsuspend */ + "ld 2, 0(1) ;" /* trigger segv" */ + : : : "memory"); + + /* This should never get here due to above segv */ + return 1; +} + +int main(void) +{ + return test_harness(tm_signal_stack, "tm_signal_stack"); +} -- 2.5.0