kernel/linux.git/arch/um, branch master

Merge tag 'uml-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2026-04-20T23:36:46+00:00

Pull uml updates from Johannes Berg: "Mostly cleanups and small things, notably: - musl libc compatibility - vDSO installation fix - TLB sync race fix for recent SMP support - build fix for 32-bit with Clang 20/21" * tag 'uml-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Disable GCOV_PROFILE_ALL on 32-bit UML with Clang 20/21 um: drivers: call kernel_strrchr() explicitly in cow_user.c um: Replace strncpy() with strnlen()+memcpy_and_pad() in strncpy_chunk_from_user() x86/um: fix vDSO installation um: Remove CONFIG_FRAME_WARN from x86_64_defconfig um: Fix pte_read() and pte_exec() for kernel mappings um: Fix potential race condition in TLB sync um: time-travel: clean up kernel-doc warnings um: avoid struct sigcontext redefinition with musl um: fix address-of CMSG_DATA() rvalue in stub

Merge tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-17T03:11:56+00:00

Pull non-MM updates from Andrew Morton: - "pid: make sub-init creation retryable" (Oleg Nesterov) Make creation of init in a new namespace more robust by clearing away some historical cruft which is no longer needed. Also some documentation fixups - "selftests/fchmodat2: Error handling and general" (Mark Brown) Fix and a cleanup for the fchmodat2() syscall selftest - "lib: polynomial: Move to math/ and clean up" (Andy Shevchenko) - "hung_task: Provide runtime reset interface for hung task detector" (Aaron Tomlin) Give administrators the ability to zero out /proc/sys/kernel/hung_task_detect_count - "tools/getdelays: use the static UAPI headers from tools/include/uapi" (Thomas Weißschuh) Teach getdelays to use the in-kernel UAPI headers rather than the system-provided ones - "watchdog/hardlockup: Improvements to hardlockup" (Mayank Rungta) Several cleanups and fixups to the hardlockup detector code and its documentation - "lib/bch: fix undefined behavior from signed left-shifts" (Josh Law) A couple of small/theoretical fixes in the bch code - "ocfs2/dlm: fix two bugs in dlm_match_regions()" (Junrui Luo) - "cleanup the RAID5 XOR library" (Christoph Hellwig) A quite far-reaching cleanup to this code. I can't do better than to quote Christoph: "The XOR library used for the RAID5 parity is a bit of a mess right now. The main file sits in crypto/ despite not being cryptography and not using the crypto API, with the generic implementations sitting in include/asm-generic and the arch implementations sitting in an asm/ header in theory. The latter doesn't work for many cases, so architectures often build the code directly into the core kernel, or create another module for the architecture code. Change this to a single module in lib/ that also contains the architecture optimizations, similar to the library work Eric Biggers has done for the CRC and crypto libraries later. After that it changes to better calling conventions that allow for smarter architecture implementations (although none is contained here yet), and uses static_call to avoid indirection function call overhead" - "lib/list_sort: Clean up list_sort() scheduling workarounds" (Kuan-Wei Chiu) Clean up this library code by removing a hacky thing which was added for UBIFS, which UBIFS doesn't actually need - "Fix bugs in extract_iter_to_sg()" (Christian Ehrhardt) Fix a few bugs in the scatterlist code, add in-kernel tests for the now-fixed bugs and fix a leak in the test itself - "kdump: Enable LUKS-encrypted dump target support in ARM64 and PowerPC" (Coiby Xu) Enable support of the LUKS-encrypted device dump target on arm64 and powerpc - "ocfs2: consolidate extent list validation into block read callbacks" (Joseph Qi) Cleanup, simplify, and make more robust ocfs2's validation of extent list fields (Kernel test robot loves mounting corrupted fs images!) * tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (127 commits) ocfs2: validate group add input before caching ocfs2: validate bg_bits during freefrag scan ocfs2: fix listxattr handling when the buffer is full doc: watchdog: fix typos etc update Sean's email address ocfs2: use get_random_u32() where appropriate ocfs2: split transactions in dio completion to avoid credit exhaustion ocfs2: remove redundant l_next_free_rec check in __ocfs2_find_path() ocfs2: validate extent block list fields during block read ocfs2: remove empty extent list check in ocfs2_dx_dir_lookup_rec() ocfs2: validate dx_root extent list fields during block read ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY ocfs2: handle invalid dinode in ocfs2_group_extend .get_maintainer.ignore: add Askar ocfs2: validate bg_list extent bounds in discontig groups checkpatch: exclude forward declarations of const structs tools/accounting: handle truncated taskstats netlink messages taskstats: set version in TGID exit notifications ocfs2/heartbeat: fix slot mapping rollback leaks on error paths arm64,ppc64le/kdump: pass dm-crypt keys to kdump kernel ...

um: Disable GCOV_PROFILE_ALL on 32-bit UML with Clang 20/21

2026-04-10T07:28:59+00:00

Clang 20 and 21 miscompute __builtin_object_size() when -fprofile-arcs is active on 32-bit UML targets, which passes incorrect object size calculations for local variables through always_inline copy_to_user() and check_copy_size(), causing spurious compile-time errors: include/linux/ucopysize.h:52:4: error: call to '__bad_copy_from' declared with 'error' attribute: copy source size is too small The regression was introduced in LLVM commit 02b8ee281947 ("[llvm] Improve llvm.objectsize computation by computing GEP, alloca and malloc parameters bound"), which shipped in Clang 20. It was fixed in LLVM by commit 45b697e610fd ("[MemoryBuiltins] Consider index type size when aggregating gep offsets"), which was backported to the LLVM 22.x release branch. The bug requires 32-bit UML + GCOV_PROFILE_ALL (which uses -fprofile-arcs), though the exact trigger depends on optimizer decisions influenced by other enabled configs. Prevent the bad combination by disabling UML's ARCH_HAS_GCOV_PROFILE_ALL on 32-bit when using Clang 20.x or 21.x. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202604030531.O6FveVgn-lkp@intel.com/ Suggested-by: Nathan Chancellor Assisted-by: Claude:claude-opus-4-6[1m] Signed-off-by: Kees Cook Link: https://patch.msgid.link/20260409052038.make.995-kees@kernel.org Signed-off-by: Johannes Berg

um: drivers: call kernel_strrchr() explicitly in cow_user.c

2026-04-08T07:25:22+00:00

Building ARCH=um on glibc >= 2.43 fails: arch/um/drivers/cow_user.c: error: implicit declaration of function 'strrchr' [-Wimplicit-function-declaration] glibc 2.43's C23 const-preserving strrchr() macro does not survive UML's global -Dstrrchr=kernel_strrchr remap from arch/um/Makefile. Call kernel_strrchr() directly in cow_user.c so the source no longer depends on the -D rewrite. Fixes: 2c51a4bc0233 ("um: fix strrchr() problems") Suggested-by: Johannes Berg Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260408070102.2325572-1-michael.bommarito@gmail.com [remove unnecessary 'extern'] Signed-off-by: Johannes Berg

arch, mm: consolidate empty_zero_page

2026-04-05T20:53:01+00:00

Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of ZERO_PAGE() to 4. Every architecture defines empty_zero_page that way or another, but for the most of them it is always a page aligned page in BSS and most definitions of ZERO_PAGE do virt_to_page(empty_zero_page). Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to the core MM and drop these definitions in architectures that do not implement colored zero page (MIPS and s390). ZERO_PAGE() remains a macro because turning it to a wrapper for a static inline causes severe pain in header dependencies. For the most part the change is mechanical, with these being noteworthy: * alpha: aliased empty_zero_page with ZERO_PGE that was also used for boot parameters. Switching to a generic empty_zero_page removes the aliasing and keeps ZERO_PGE for boot parameters only * arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of ZERO_PAGE() is kept intact. * m68k/parisc/um: allocated empty_zero_page from memblock, although they do not support zero page coloring and having it in BSS will work fine. * sparc64 can have empty_zero_page in BSS rather allocate it, but it can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE() but instead of allocating it, make mem_map_zero point to empty_zero_page. * sh: used empty_zero_page for boot parameters at the very early boot. Rename the parameters page to boot_params_page and let sh use the generic empty_zero_page. * hexagon: had an amusing comment about empty_zero_page /* A handy thing to have if one has the RAM. Declared in head.S */ that unfortunately had to go :) Link: https://lkml.kernel.org/r/20260211103141.3215197-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Helge Deller [parisc] Tested-by: Helge Deller [parisc] Reviewed-by: Christophe Leroy (CS GROUP) Acked-by: Dave Hansen Acked-by: Catalin Marinas Acked-by: Magnus Lindholm [alpha] Acked-by: Dinh Nguyen [nios2] Acked-by: Andreas Larsson [sparc] Acked-by: David Hildenbrand (Arm) Acked-by: Liam R. Howlett Cc: "Borislav Petkov (AMD)" Cc: David S. Miller Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Huacai Chen Cc: Ingo Molnar Cc: Johannes Berg Cc: John Paul Adrian Glaubitz Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Hocko Cc: Michal Simek Cc: Palmer Dabbelt Cc: Richard Weinberger Cc: Russell King Cc: Stafford Horne Cc: Suren Baghdasaryan Cc: Vineet Gupta Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

xor: make xor.ko self-contained in lib/raid/

2026-04-03T06:36:20+00:00

Move the asm/xor.h headers to lib/raid/xor/$(SRCARCH)/xor_arch.h and include/linux/raid/xor_impl.h to lib/raid/xor/xor_impl.h so that the xor.ko module implementation is self-contained in lib/raid/. As this remove the asm-generic mechanism a new kconfig symbol is added to indicate that a architecture-specific implementations exists, and xor_arch.h should be included. Link: https://lkml.kernel.org/r/20260327061704.3707577-22-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Eric Biggers Tested-by: Eric Biggers Cc: Albert Ou Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Andreas Larsson Cc: Anton Ivanov Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Chris Mason Cc: Christian Borntraeger Cc: Dan Williams Cc: David S. Miller Cc: David Sterba Cc: Heiko Carstens Cc: Herbert Xu Cc: "H. Peter Anvin" Cc: Huacai Chen Cc: Ingo Molnar Cc: Jason A. Donenfeld Cc: Johannes Berg Cc: Li Nan Cc: Madhavan Srinivasan Cc: Magnus Lindholm Cc: Matt Turner Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Richard Henderson Cc: Richard Weinberger Cc: Russell King Cc: Song Liu Cc: Sven Schnelle Cc: Ted Ts'o Cc: Vasily Gorbik Cc: WANG Xuerui Cc: Will Deacon Signed-off-by: Andrew Morton

um/xor: cleanup xor.h

2026-04-03T06:36:16+00:00

Since commit c055e3eae0f1 ("crypto: xor - use ktime for template benchmarking") the benchmarking works just fine even for TT_MODE_INFCPU, so drop the workarounds. Note that for CPUs supporting AVX2, which includes almost everything built in the last 10 years, the AVX2 implementation is forced anyway. CONFIG_X86_32 is always correctly set for UM in arch/x86/um/Kconfig, so don't override it either. Link: https://lkml.kernel.org/r/20260327061704.3707577-5-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Richard Weinberger Reviewed-by: Eric Biggers Tested-by: Eric Biggers Cc: Albert Ou Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Andreas Larsson Cc: Anton Ivanov Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Chris Mason Cc: Christian Borntraeger Cc: Dan Williams Cc: David S. Miller Cc: David Sterba Cc: Heiko Carstens Cc: Herbert Xu Cc: "H. Peter Anvin" Cc: Huacai Chen Cc: Ingo Molnar Cc: Jason A. Donenfeld Cc: Johannes Berg Cc: Li Nan Cc: Madhavan Srinivasan Cc: Magnus Lindholm Cc: Matt Turner Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Richard Henderson Cc: Russell King Cc: Song Liu Cc: Sven Schnelle Cc: Ted Ts'o Cc: Vasily Gorbik Cc: WANG Xuerui Cc: Will Deacon Signed-off-by: Andrew Morton

um: Replace strncpy() with strnlen()+memcpy_and_pad() in strncpy_chunk_from_user()

2026-03-27T07:21:09+00:00

Replace the deprecated[1] strncpy() with strnlen() on the source followed by memcpy_and_pad(). This function is a chunk callback for UML's strncpy_from_user() implementation, called by buffer_op() to process userspace memory one page at a time. The source is a kernel-mapped userspace address that is not guaranteed to be NUL-terminated; "len" bounds how many bytes to read from it. By measuring the source string length first with strnlen(), we avoid reading past the NUL terminator in the source. memcpy_and_pad() then copies the string content and zero-fills the remainder of the chunk, preserving the original strncpy() behavior exactly: copy up to the first NUL, then pad with zeros to the full length. strtomem_pad() would be the idiomatic helper for this strnlen() + memcpy_and_pad() pattern, but it requires a compile-time-determinable destination size (via ARRAY_SIZE()). Here the destination is a char * into a caller-provided buffer and the chunk length is a runtime value, so the explicit two-step is necessary. No behavioral change: the same bytes are written to the destination (string content followed by zero padding), the pointer advances by the same amount, and the NUL-found return condition is unchanged. Link: https://github.com/KSPP/linux/issues/90 [1] Signed-off-by: Kees Cook Link: https://patch.msgid.link/20260323171713.work.839-kees@kernel.org Signed-off-by: Johannes Berg

um: Remove CONFIG_FRAME_WARN from x86_64_defconfig

2026-03-21T09:43:10+00:00

The CONFIG_FRAME_WARN=1024 setting in x86_64_defconfig originates from arch/um/defconfig, which was split into i386_defconfig and x86_64_defconfig by commit e40f04d040c6 ("arch/um: make it work with defconfig and x86_64"). Currently, it's even smaller than the default on 32bit (i.e., 1280). It's no longer suitable for 64bit. Building with x86_64_defconfig triggers the following warning: lib/maple_tree.c: In function ‘mas_wr_bnode’: lib/maple_tree.c:3740:1: warning: the frame size of 1056 bytes is larger than 1024 bytes [-Wframe-larger-than=] 3740 | } | ^ Since we have a larger CONFIG_KERNEL_STACK_ORDER on 64bit (twice that of 32bit) by default, we could increase CONFIG_FRAME_WARN accordingly. Let's remove the CONFIG_FRAME_WARN=1024 setting from x86_64_defconfig and just use the default value (2048 for 64bit) defined in lib/Kconfig.debug, as we do for 32bit. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260308060406.2772832-1-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg

um: Fix pte_read() and pte_exec() for kernel mappings

2026-03-21T09:42:24+00:00

The pte_read() and pte_exec() helpers are only used during the TLB sync to determine the read/exec permissions for mmap. However, for kernel mappings, they will always return 0. This leads to kern_map() having to unconditionally set the exec flag to 1 and the read flag unexpectedly always being 0. Remove the unnecessary check for the _PAGE_USER bit in these helpers to ensure that the kernel mapping permissions can be correctly determined. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260302235224.1915380-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg