linux/lib/Kconfig.debug, branch v6.8

lib/Kconfig.debug: TEST_IOV_ITER depends on MMU

2024-02-20T22:20:48Z

Trying to run the iov_iter unit test on a nommu system such as the qemu kc705-nommu emulation results in a crash. KTAP version 1 # Subtest: iov_iter # module: kunit_iov_iter 1..9 BUG: failure at mm/nommu.c:318/vmap()! Kernel panic - not syncing: BUG! The test calls vmap() directly, but vmap() is not supported on nommu systems, causing the crash. TEST_IOV_ITER therefore needs to depend on MMU. Link: https://lkml.kernel.org/r/20240208153010.1439753-1-linux@roeck-us.net Fixes: 2d71340ff1d4 ("iov_iter: Kunit tests for copying to/from an iterator") Signed-off-by: Guenter Roeck Cc: David Howells Cc: Signed-off-by: Andrew Morton

Merge tag 'riscv-for-linus-6.8-mw4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2024-01-20T19:06:04Z

Pull more RISC-V updates from Palmer Dabbelt: - Support for tuning for systems with fast misaligned accesses. - Support for SBI-based suspend. - Support for the new SBI debug console extension. - The T-Head CMOs now use PA-based flushes. - Support for enabling the V extension in kernel code. - Optimized IP checksum routines. - Various ftrace improvements. - Support for archrandom, which depends on the Zkr extension. - The build is no longer broken under NET=n, KUNIT=y for ports that don't define their own ipv6 checksum. * tag 'riscv-for-linus-6.8-mw4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (56 commits) lib: checksum: Fix build with CONFIG_NET=n riscv: lib: Check if output in asm goto supported riscv: Fix build error on rv32 + XIP riscv: optimize ELF relocation function in riscv RISC-V: Implement archrandom when Zkr is available riscv: Optimize hweight API with Zbb extension riscv: add dependency among Image(.gz), loader(.bin), and vmlinuz.efi samples: ftrace: Add RISC-V support for SAMPLE_FTRACE_DIRECT[_MULTI] riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support riscv: ftrace: Make function graph use ftrace directly riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY lib/Kconfig.debug: Update AS_HAS_NON_CONST_LEB128 comment and name riscv: Restrict DWARF5 when building with LLVM to known working versions riscv: Hoist linker relaxation disabling logic into Kconfig kunit: Add tests for csum_ipv6_magic and ip_fast_csum riscv: Add checksum library riscv: Add checksum header riscv: Add static key for misaligned accesses asm-generic: Improve csum_fold RISC-V: selftests: cbo: Ensure asm operands match constraints ...

lib/Kconfig.debug: Update AS_HAS_NON_CONST_LEB128 comment and name

2024-01-18T02:08:28Z

Fangrui noted that the comment around CONFIG_AS_HAS_NON_CONST_LEB128 could be made more accurate because explicit .sleb128 directives are not emitted, only .uleb128 directives are. Rename the symbol to CONFIG_AS_HAS_NON_CONST_ULEB128 as a result. Further clarifications include replacing "symbol deltas" with the more accurate "label differences", noting that this issue has been resolved in newer binutils (2.41+), and it only occurs when a port uses RISC-V style linker relaxation. Suggested-by: Fangrui Song Signed-off-by: Nathan Chancellor Reviewed-by: Charlie Jenkins Link: https://lore.kernel.org/r/20231205-riscv-restrict-dwarf5-llvm-v2-3-aedf00a382ac@kernel.org Signed-off-by: Palmer Dabbelt

riscv: Restrict DWARF5 when building with LLVM to known working versions

2024-01-18T02:08:27Z

LLVM prior to 18.0.0 would generate incorrect debug info for DWARF5 due to linker relaxation, which was worked around in clang by defaulting RISC-V to DWARF4 [1]. Unfortunately, this workaround does not work for the kernel because the DWARF version can be independently changed from the default in Kconfig. Do not allow DWARF5 to be selected for RISC-V when using linker relaxation (ld.lld >= 15.0.0) and a version of LLVM that does not have the fixes (the integrated assembler [2] and ld.lld [3] < 18.0.0) necessary to generate the correct debug info. Link: https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6 [1] Link: https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a [2] Link: https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77 [3] Signed-off-by: Nathan Chancellor Reviewed-by: Fangrui Song Link: https://lore.kernel.org/r/20231205-riscv-restrict-dwarf5-llvm-v2-2-aedf00a382ac@kernel.org Signed-off-by: Palmer Dabbelt

lib/Kconfig.debug: disable CONFIG_DEBUG_INFO_BTF for Hexagon

2024-01-12T23:20:45Z

pahole, which generates BTF, relies on elfutils to process DWARF debug info. Because kernel modules are relocatable files, elfutils needs to resolve relocations when processing the DWARF .debug sections. Hexagon is not supported in binutils or elfutils, so elfutils is unable to process relocations in kernel modules, causing pahole to crash during BTF generation. Do not allow CONFIG_DEBUG_INFO_BTF to be selected for Hexagon until it is supported in elfutils, so that there are no more cryptic build failures during BTF generation. Link: https://lkml.kernel.org/r/20240105-hexagon-disable-btf-v1-1-ddab073e7f74@kernel.org Signed-off-by: Nathan Chancellor Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202312192107.wMIKiZWw-lkp@intel.com/ Suggested-by: Nick Desaulniers Acked-by: Brian Cain Cc: Arnaldo Carvalho de Melo Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2024-01-09-10-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-01-09T19:46:20Z

Pull non-MM updates from Andrew Morton: "Quite a lot of kexec work this time around. Many singleton patches in many places. The notable patch series are: - nilfs2 folio conversion from Matthew Wilcox in 'nilfs2: Folio conversions for file paths'. - Additional nilfs2 folio conversion from Ryusuke Konishi in 'nilfs2: Folio conversions for directory paths'. - IA64 remnant removal in Heiko Carstens's 'Remove unused code after IA-64 removal'. - Arnd Bergmann has enabled the -Wmissing-prototypes warning everywhere in 'Treewide: enable -Wmissing-prototypes'. This had some followup fixes: - Nathan Chancellor has cleaned up the hexagon build in the series 'hexagon: Fix up instances of -Wmissing-prototypes'. - Nathan also addressed some s390 warnings in 's390: A couple of fixes for -Wmissing-prototypes'. - Arnd Bergmann addresses the same warnings for MIPS in his series 'mips: address -Wmissing-prototypes warnings'. - Baoquan He has made kexec_file operate in a top-down-fitting manner similar to kexec_load in the series 'kexec_file: Load kernel at top of system RAM if required' - Baoquan He has also added the self-explanatory 'kexec_file: print out debugging message if required'. - Some checkstack maintenance work from Tiezhu Yang in the series 'Modify some code about checkstack'. - Douglas Anderson has disentangled the watchdog code's logging when multiple reports are occurring simultaneously. The series is 'watchdog: Better handling of concurrent lockups'. - Yuntao Wang has contributed some maintenance work on the crash code in 'crash: Some cleanups and fixes'" * tag 'mm-nonmm-stable-2024-01-09-10-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (157 commits) crash_core: fix and simplify the logic of crash_exclude_mem_range() x86/crash: use SZ_1M macro instead of hardcoded value x86/crash: remove the unused image parameter from prepare_elf_headers() kdump: remove redundant DEFAULT_CRASH_KERNEL_LOW_SIZE scripts/decode_stacktrace.sh: strip unexpected CR from lines watchdog: if panicking and we dumped everything, don't re-enable dumping watchdog/hardlockup: use printk_cpu_sync_get_irqsave() to serialize reporting watchdog/softlockup: use printk_cpu_sync_get_irqsave() to serialize reporting watchdog/hardlockup: adopt softlockup logic avoiding double-dumps kexec_core: fix the assignment to kimage->control_page x86/kexec: fix incorrect end address passed to kernel_ident_mapping_init() lib/trace_readwrite.c:: replace asm-generic/io with linux/io nilfs2: cpfile: fix some kernel-doc warnings stacktrace: fix kernel-doc typo scripts/checkstack.pl: fix no space expression between sp and offset x86/kexec: fix incorrect argument passed to kexec_dprintk() x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs nilfs2: add missing set_freezable() for freezable kthread kernel: relay: remove relay_file_splice_read dead code, doesn't work docs: submit-checklist: remove all of "make namespacecheck" ...

Merge tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2024-01-09T18:36:07Z

Pull slab updates from Vlastimil Babka: - SLUB: delayed freezing of CPU partial slabs (Chengming Zhou) Freezing is an operation involving double_cmpxchg() that makes a slab exclusive for a particular CPU. Chengming noticed that we use it also in situations where we are not yet installing the slab as the CPU slab, because freezing also indicates that the slab is not on the shared list. This results in redundant freeze/unfreeze operation and can be avoided by marking separately the shared list presence by reusing the PG_workingset flag. This approach neatly avoids the issues described in 9b1ea29bc0d7 ("Revert "mm, slub: consider rest of partial list if acquire_slab() fails"") as we can now grab a slab from the shared list in a quick and guaranteed way without the cmpxchg_double() operation that amplifies the lock contention and can fail. As a result, lkp has reported 34.2% improvement of stress-ng.rawudp.ops_per_sec - SLAB removal and SLUB cleanups (Vlastimil Babka) The SLAB allocator has been deprecated since 6.5 and nobody has objected so far. We agreed at LSF/MM to wait until the next LTS, which is 6.6, so we should be good to go now. This doesn't yet erase all traces of SLAB outside of mm/ so some dead code, comments or documentation remain, and will be cleaned up gradually (some series are already in the works). Removing the choice of allocators has already allowed to simplify and optimize the code wiring up the kmalloc APIs to the SLUB implementation. * tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (34 commits) mm/slub: free KFENCE objects in slab_free_hook() mm/slub: handle bulk and single object freeing separately mm/slub: introduce __kmem_cache_free_bulk() without free hooks mm/slub: fix bulk alloc and free stats mm/slub: optimize free fast path code layout mm/slub: optimize alloc fastpath code layout mm/slub: remove slab_alloc() and __kmem_cache_alloc_lru() wrappers mm/slab: move kmalloc() functions from slab_common.c to slub.c mm/slab: move kmalloc_slab() to mm/slab.h mm/slab: move kfree() from slab_common.c to slub.c mm/slab: move struct kmem_cache_node from slab.h to slub.c mm/slab: move memcg related functions from slab.h to slub.c mm/slab: move pre/post-alloc hooks from slab.h to slub.c mm/slab: consolidate includes in the internal mm/slab.h mm/slab: move the rest of slub_def.h to mm/slab.h mm/slab: move struct kmem_cache_cpu declaration to slub.c mm/slab: remove mm/slab.c and slab_def.h mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs mm/slab: remove CONFIG_SLAB code from slab common code cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks ...

lib: add note about process exit message for DEBUG_STACK_USAGE

2023-12-29T20:22:26Z

DEBUG_STACK_USAGE doesn't only have an influence on the output of sysrq-T and sysrq-P, it also enables a message at process exit. See check_stack_usage() in kernel/exit.c where this is implemented. Link: https://lkml.kernel.org/r/20231219182808.210284-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Cc: Douglas Anderson Cc: Geert Uytterhoeven Cc: Kees Cook Cc: Marco Elver Cc: "Paul E. McKenney" Cc: Pengutronix Kernel Team Cc: Petr Mladek Cc: Randy Dunlap Cc: Stephen Boyd Cc: Zhaoyang Huang Signed-off-by: Andrew Morton

kcov: remove stale RANDOMIZE_BASE text

2023-12-20T23:02:57Z

The Kconfig help text for CONFIG_KCOV describes that recorded PC values will not be stable across machines or reboots when RANDOMIZE_BASE is selected. This was the case when KCOV was introduced in commit: 5c9a8750a6409c63 ("kernel: add kcov code coverage") However, this changed in commit: 4983f0ab7ffaad1e ("kcov: make kcov work properly with KASLR enabled") Since that commit KCOV always subtracts the KASLR offset from PC values, which ensures that these are stable across machines and across reboots even when RANDOMIZE_BASE is selected. Unfortunately, that commit failed to update the Kconfig help text, which still suggests disabling RANDOMIZE_BASE even though this is no longer necessary. Remove the stale Kconfig text. Link: https://lkml.kernel.org/r/20231204171807.3313022-1-mark.rutland@arm.com Reported-by: Borislav Petkov Signed-off-by: Mark Rutland Reviewed-by: Dmitry Vyukov Cc: Alexander Popov Cc: Andrey Konovalov Signed-off-by: Andrew Morton

cred: get rid of CONFIG_DEBUG_CREDENTIALS

2023-12-15T22:19:48Z

This code is rarely (never?) enabled by distros, and it hasn't caught anything in decades. Let's kill off this legacy debug code. Suggested-by: Linus Torvalds Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds