kernel/drivers/misc/lkdtm, branch linux-6.9.y

lkdtm: Disable CFI checking for perms functions

2024-05-30T07:44:09Z

[ Upstream commit fb28a8862dc4b5bf8e44578338f35d9c6c68339d ] The EXEC_RODATA test plays a lot of tricks to live in the .rodata section, and once again ran into objtool's (completely reasonable) assumptions that executable code should live in an executable section. However, this manifested only under CONFIG_CFI_CLANG=y, as one of the .cfi_sites was pointing into the .rodata section. Since we're testing non-CFI execution properties in perms.c (and rodata.c), we can disable CFI for the involved functions, and remove the CFI arguments from rodata.c entirely. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202308301532.d7acf63e-oliver.sang@intel.com Fixes: 6342a20efbd8 ("objtool: Add elf_create_section_pair()") Link: https://lore.kernel.org/r/20240430234953.work.760-kees@kernel.org Signed-off-by: Kees Cook Signed-off-by: Sasha Levin

lkdtm/bugs: Improve warning message for compilers without counted_by support

2024-03-22T23:25:31Z

The current message for telling the user that their compiler does not support the counted_by attribute in the FAM_BOUNDS test does not make much sense either grammatically or semantically. Fix it to make it correct in both aspects. Signed-off-by: Nathan Chancellor Reviewed-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20240321-lkdtm-improve-lack-of-counted_by-msg-v1-1-0fbf7481a29c@kernel.org Signed-off-by: Kees Cook

Merge tag 'slab-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2024-03-13T03:14:54Z

Pull slab updates from Vlastimil Babka: - Freelist loading optimization (Chengming Zhou) When the per-cpu slab is depleted and a new one loaded from the cpu partial list, optimize the loading to avoid an irq enable/disable cycle. This results in a 3.5% performance improvement on the "perf bench sched messaging" test. - Kernel boot parameters cleanup after SLAB removal (Xiongwei Song) Due to two different main slab implementations we've had boot parameters prefixed either slab_ and slub_ with some later becoming an alias as both implementations gained the same functionality (i.e. slab_nomerge vs slub_nomerge). In order to eventually get rid of the implementation-specific names, the canonical and documented parameters are now all prefixed slab_ and the slub_ variants become deprecated but still working aliases. - SLAB_ kmem_cache creation flags cleanup (Vlastimil Babka) The flags had hardcoded #define values which became tedious and error-prone when adding new ones. Assign the values via an enum that takes care of providing unique bit numbers. Also deprecate SLAB_MEM_SPREAD which was only used by SLAB, so it's a no-op since SLAB removal. Assign it an explicit zero value. The removals of the flag usage are handled independently in the respective subsystems, with a final removal of any leftover usage planned for the next release. - Misc cleanups and fixes (Chengming Zhou, Xiaolei Wang, Zheng Yejian) Includes removal of unused code or function parameters and a fix of a memleak. * tag 'slab-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: slab: remove PARTIAL_NODE slab_state mm, slab: remove memcg_from_slab_obj() mm, slab: remove the corner case of inc_slabs_node() mm/slab: Fix a kmemleak in kmem_cache_destroy() mm, slab, kasan: replace kasan_never_merge() with SLAB_NO_MERGE mm, slab: use an enum to define SLAB_ cache creation flags mm, slab: deprecate SLAB_MEM_SPREAD flag mm, slab: fix the comment of cpu partial list mm, slab: remove unused object_size parameter in kmem_cache_flags() mm/slub: remove parameter 'flags' in create_kmalloc_caches() mm/slub: remove unused parameter in next_freelist_entry() mm/slub: remove full list manipulation for non-debug slab mm/slub: directly load freelist from cpu partial slab in the likely case mm/slub: make the description of slab_min_objects helpful in doc mm/slub: replace slub_$params with slab_$params in slub.rst mm/slub: unify all sl[au]b parameters with "slab_$param" Documentation: kernel-parameters: remove noaliencache

lkdtm/bugs: In lkdtm_HUNG_TASK() use BUG(), not BUG_ON(1)

2024-02-01T17:44:07Z

In commit edb6538da3df ("lkdtm/bugs: Adjust lkdtm_HUNG_TASK() to avoid tail call optimization") we marked lkdtm_HUNG_TASK() as __noreturn. The compiler gets unhappy if it thinks a __noreturn function might return, so there's a BUG_ON(1) at the end. Any human can see that the function won't return and the compiler can figure that out too. Except when it can't. The MIPS architecture defines HAVE_ARCH_BUG_ON and defines its own version of BUG_ON(). The MIPS version of BUG_ON() is not a macro but is instead an inline function. Apparently this prevents the compiler from realizing that the condition to BUG_ON() is constant and that the function will never return. Let's change the BUG_ON(1) to just BUG(), which it should have been to begin with. The only reason I used BUG_ON(1) to begin with was because I was used to using WARN_ON(1) when writing test code and WARN() and BUG() are oddly inconsistent in this manner. :-/ Fixes: edb6538da3df ("lkdtm/bugs: Adjust lkdtm_HUNG_TASK() to avoid tail call optimization") Signed-off-by: Douglas Anderson Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202401262204.wUFKRYZF-lkp@intel.com/ Acked-by: Arnd Bergmann Link: https://lore.kernel.org/r/20240126072852.1.Ib065e528a8620474a72f15baa2feead1f3d89865@changeid Signed-off-by: Kees Cook

lkdtm/bugs: Adjust lkdtm_HUNG_TASK() to avoid tail call optimization

2024-02-01T17:44:07Z

When testing with lkdtm_HUNG_TASK() and looking at the output, I expected to see lkdtm_HUNG_TASK() in the stack crawl but it wasn't there. Instead, the top function on at least some devices was schedule() due to tail call optimization. Let's do two things to help here: 1. We'll mark this as "__noreturn". On GCC at least this is documented to prevent tail call optimization. The docs [1] say "In order to preserve backtraces, GCC will never turn calls to noreturn functions into tail calls." 2. We'll add a BUG_ON(1) at the end which means that schedule() is no longer a tail call. Note that this is potentially important because if we _did_ end up returning from schedule() due to some weird issue then we'd potentially be violating the "noreturn" that we told the compiler about. BUG is the right thing to do here. [1] https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20240122164935.2.I26e8f68c312824fcc80c19d4e91de2d2bef958f0@changeid Signed-off-by: Kees Cook

lkdtm: Make lkdtm_do_action() return to avoid tail call optimization

2024-02-01T17:44:07Z

The comments for lkdtm_do_action() explicitly call out that it shouldn't be inlined because we want it to show up in stack crawls. However, at least with some compilers / options it's still vanishing due to tail call optimization. Let's add a return value to the function to make it harder for the compiler to do tail call optimization here. Now that we have a return value, we can actually use it in the callers, which is a minor improvement in the code. Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20240122164935.1.I345e485f36babad76370c59659a706723750d950@changeid Signed-off-by: Kees Cook

mm/slub: unify all sl[au]b parameters with "slab_$param"

2024-01-22T09:31:08Z

Since the SLAB allocator has been removed, so we can clean up the sl[au]b_$params. With only one slab allocator left, it's better to use the generic "slab" term instead of "slub" which is an implementation detail, which is pointed out by Vlastimil Babka. For more information please see [1]. Hence, we are going to use "slab_$param" as the primary prefix. This patch is changing the following slab parameters - slub_max_order - slub_min_order - slub_min_objects - slub_debug to - slab_max_order - slab_min_order - slab_min_objects - slab_debug as the primary slab parameters for all references of them in docs and comments. But this patch won't change variables and functions inside slub as we will have wider slub/slab change. Meanwhile, "slub_$params" can also be passed by command line, which is to keep backward compatibility. Also mark all "slub_$params" as legacy. Remove the separate descriptions for slub_[no]merge, append legacy tip for them at the end of descriptions of slab_[no]merge. [1] https://lore.kernel.org/linux-mm/7512b350-4317-21a0-fab3-4101bc4d8f7a@suse.cz/ Signed-off-by: Xiongwei Song Reviewed-by: Vlastimil Babka Signed-off-by: Vlastimil Babka

lkdtm: Add kfence read after free crash type

2023-12-01T17:51:43Z

Add the ability to allocate memory from kfence and trigger a read after free on that memory to validate that kfence is working properly. This is used by ChromeOS integration tests to validate that kfence errors can be collected on user devices and parsed properly. Cc: Alexander Potapenko Acked-by: Marco Elver Cc: Dmitry Vyukov Cc: Andrew Morton Cc: kasan-dev@googlegroups.com Signed-off-by: Stephen Boyd Link: https://lore.kernel.org/r/20231129214413.3156334-1-swboyd@chromium.org Signed-off-by: Kees Cook

Merge tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2023-11-08T17:21:18Z

Pull RISC-V updates from Palmer Dabbelt: - Support for cbo.zero in userspace - Support for CBOs on ACPI-based systems - A handful of improvements for the T-Head cache flushing ops - Support for software shadow call stacks - Various cleanups and fixes * tag 'riscv-for-linus-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (31 commits) RISC-V: hwprobe: Fix vDSO SIGSEGV riscv: configs: defconfig: Enable configs required for RZ/Five SoC riscv: errata: prefix T-Head mnemonics with th. riscv: put interrupt entries into .irqentry.text riscv: mm: Update the comment of CONFIG_PAGE_OFFSET riscv: Using TOOLCHAIN_HAS_ZIHINTPAUSE marco replace zihintpause riscv/mm: Fix the comment for swap pte format RISC-V: clarify the QEMU workaround in ISA parser riscv: correct pt_level name via pgtable_l5/4_enabled RISC-V: Provide pgtable_l5_enabled on rv32 clocksource: timer-riscv: Increase rating of clock_event_device for Sstc clocksource: timer-riscv: Don't enable/disable timer interrupt lkdtm: Fix CFI_BACKWARD on RISC-V riscv: Use separate IRQ shadow call stacks riscv: Implement Shadow Call Stack riscv: Move global pointer loading to a macro riscv: Deduplicate IRQ stack switching riscv: VMAP_STACK overflow detection thread-safe RISC-V: cacheflush: Initialize CBO variables on ACPI systems RISC-V: ACPI: RHCT: Add function to get CBO block sizes ...

lkdtm: Fix CFI_BACKWARD on RISC-V

2023-10-27T21:43:10Z

On RISC-V, the return address is before the current frame pointer, unlike on most other architectures. Use the correct offset on RISC-V to fix the CFI_BACKWARD test. Signed-off-by: Sami Tolvanen Acked-by: Kees Cook Tested-by: Nathan Chancellor Link: https://lore.kernel.org/r/20230927224757.1154247-14-samitolvanen@google.com Signed-off-by: Palmer Dabbelt