Skip to main content

Browse the archive

https://github.com/torvalds/linux
02 December 2022, 17:28:11 UTC
Revision a4412fdd49dc011bcc2c0d81ac4cab7457092650 authored by Steven Rostedt (Google) on 21 November 2022, 15:44:03 UTC, committed by Linus Torvalds on 01 December 2022, 21:14:21 UTC 
error-injection: Add prompt for function error injection
 
The config to be able to inject error codes into any function annotated
with ALLOW_ERROR_INJECTION() is enabled when FUNCTION_ERROR_INJECTION is
enabled.  But unfortunately, this is always enabled on x86 when KPROBES
is enabled, and there's no way to turn it off.

As kprobes is useful for observability of the kernel, it is useful to
have it enabled in production environments.  But error injection should
be avoided.  Add a prompt to the config to allow it to be disabled even
when kprobes is enabled, and get rid of the "def_bool y".

This is a kernel debug feature (it's in Kconfig.debug), and should have
never been something enabled by default.

Cc: stable@vger.kernel.org
Fixes: 540adea3809f6 ("error-injection: Separate error-injection from kprobe")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 355479c
Raw File
Tip revision: a4412fdd49dc011bcc2c0d81ac4cab7457092650 authored by Steven Rostedt (Google) on 21 November 2022, 15:44:03 UTC
error-injection: Add prompt for function error injection
Tip revision: a4412fd
binfmt_elf_test.c 
// SPDX-License-Identifier: GPL-2.0-only
#include <kunit/test.h>

static void total_mapping_size_test(struct kunit *test)
{
	struct elf_phdr empty[] = {
		{ .p_type = PT_LOAD, .p_vaddr = 0, .p_memsz = 0, },
		{ .p_type = PT_INTERP, .p_vaddr = 10, .p_memsz = 999999, },
	};
	/*
	 * readelf -lW /bin/mount | grep '^  .*0x0' | awk '{print "\t\t{ .p_type = PT_" \
	 *				$1 ", .p_vaddr = " $3 ", .p_memsz = " $6 ", },"}'
	 */
	struct elf_phdr mount[] = {
		{ .p_type = PT_PHDR, .p_vaddr = 0x00000040, .p_memsz = 0x0002d8, },
		{ .p_type = PT_INTERP, .p_vaddr = 0x00000318, .p_memsz = 0x00001c, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x00000000, .p_memsz = 0x0033a8, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x00004000, .p_memsz = 0x005c91, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x0000a000, .p_memsz = 0x0022f8, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x0000d330, .p_memsz = 0x000d40, },
		{ .p_type = PT_DYNAMIC, .p_vaddr = 0x0000d928, .p_memsz = 0x000200, },
		{ .p_type = PT_NOTE, .p_vaddr = 0x00000338, .p_memsz = 0x000030, },
		{ .p_type = PT_NOTE, .p_vaddr = 0x00000368, .p_memsz = 0x000044, },
		{ .p_type = PT_GNU_PROPERTY, .p_vaddr = 0x00000338, .p_memsz = 0x000030, },
		{ .p_type = PT_GNU_EH_FRAME, .p_vaddr = 0x0000b490, .p_memsz = 0x0001ec, },
		{ .p_type = PT_GNU_STACK, .p_vaddr = 0x00000000, .p_memsz = 0x000000, },
		{ .p_type = PT_GNU_RELRO, .p_vaddr = 0x0000d330, .p_memsz = 0x000cd0, },
	};
	size_t mount_size = 0xE070;
	/* https://lore.kernel.org/linux-fsdevel/YfF18Dy85mCntXrx@fractal.localdomain */
	struct elf_phdr unordered[] = {
		{ .p_type = PT_LOAD, .p_vaddr = 0x00000000, .p_memsz = 0x0033a8, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x0000d330, .p_memsz = 0x000d40, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x00004000, .p_memsz = 0x005c91, },
		{ .p_type = PT_LOAD, .p_vaddr = 0x0000a000, .p_memsz = 0x0022f8, },
	};

	/* No headers, no size. */
	KUNIT_EXPECT_EQ(test, total_mapping_size(NULL, 0), 0);
	KUNIT_EXPECT_EQ(test, total_mapping_size(empty, 0), 0);
	/* Empty headers, no size. */
	KUNIT_EXPECT_EQ(test, total_mapping_size(empty, 1), 0);
	/* No PT_LOAD headers, no size. */
	KUNIT_EXPECT_EQ(test, total_mapping_size(&empty[1], 1), 0);
	/* Empty PT_LOAD and non-PT_LOAD headers, no size. */
	KUNIT_EXPECT_EQ(test, total_mapping_size(empty, 2), 0);

	/* Normal set of PT_LOADS, and expected size. */
	KUNIT_EXPECT_EQ(test, total_mapping_size(mount, ARRAY_SIZE(mount)), mount_size);
	/* Unordered PT_LOADs result in same size. */
	KUNIT_EXPECT_EQ(test, total_mapping_size(unordered, ARRAY_SIZE(unordered)), mount_size);
}

static struct kunit_case binfmt_elf_test_cases[] = {
	KUNIT_CASE(total_mapping_size_test),
	{},
};

static struct kunit_suite binfmt_elf_test_suite = {
	.name = KBUILD_MODNAME,
	.test_cases = binfmt_elf_test_cases,
};

kunit_test_suite(binfmt_elf_test_suite);
back to top