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2026-06-16Merge tag 'fbdev-for-7.2-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev Pull fbdev updates from Helge Deller: "Beside the removal of the Hercules monochrome ISA graphics driver and the corresponding text console driver, there is just the typical maintanance with smaller driver fixes and cleanups: Removal of drivers: - Hercules monochrome ISA graphics adapter driver (Ethan Nelson-Moore) - Hercules mdacon console driver (Ethan Nelson-Moore) Changes affecting many drivers at once: - possible memory leak fixes in various drivers (Abdun Nihaal) - many conversions to use strscpy() (David Laight) - Use named initializers in drivers (Uwe Kleine-König) Code fixes: - fbcon: don't suspend/resume when vc is graphics mode (Lu Yao) - modedb: fix a possible UAF in fb_find_mode() (Tuo Li) - modedb: Fix entry for 1920x1080-60 mode (Steffen Persvold) - arm: Export acorndata_8x8 font symbol for bootloader (Helge Deller) - omap2: fix use-after-free in omapfb_mmap (Hongling Zeng) Cleanups: - pxa168fb: use devm_ioremap_resource() (Alberto Arostegui) - provice helpers for fb_set_var() and fb_blank() and fbcon updates (Thomas Zimmermann) - fbcon: Use correct type for vc_resize() return value (Jiacheng Yu) - chipsfb: add missing MODULE_DESCRIPTION() macro (Rahman Mahmutović) - sunxvr2500: replace printk with device-aware logging functions (Rahman Mahmutović) - sm712: Fix operator precedence in big_swap macro (Li RongQing) - imxfb: Use of_device_get_match_data() (Rosen Penev) - atmel_lcdfb: Use of_device_get_match_data() (Rosen Penev) Documentation fixes: - grvga: Fix CLUT register address offset in comment (Eduardo Silva) - omap/dss: Fix stale modedb.c path (Costa Shulyupin) - correct CONFIG_FB_TILEBLITTING macro name in #endif comment (Ethan Nelson-Moore)" * tag 'fbdev-for-7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev: (43 commits) fbdev: modedb: Fix misaligned fields in the 1920x1080-60 mode fbdev: modedb: fix a possible UAF in fb_find_mode() fbdev: s3fb: Use strscpy() to copy strings into arrays fbdev: sm501fb: Fix buffer errors in OF binding code fbcon: correct CONFIG_FB_TILEBLITTING macro name in #endif comment fbdev/arm: Export acorndata_8x8 font symbol for bootloader fbdev: mmpfb: Use strscpy() to copy device name fbdev: sisfb: Replace strlen() strcpy() pair with strscpy() fbdev: rivafb: Use strscpy() to copy device name fbdev: cyber2000fb: Use strscpy() to copy device name fbdev: atmel_lcdfb: Use strscpy() to copy device name fbdev: Do not export fbcon from fbdev fbdev: Wrap fbcon updates from vga-switcheroo in helper fbdev: Wrap user-invoked calls to fb_blank() in helper fbdev: Wrap user-invoked calls to fb_set_var() in helper fbdev: omap2: fix use-after-free in omapfb_mmap docs: omap/dss: Fix stale modedb.c path fbdev: pxa168fb: use devm_ioremap_resource() for MMIO fbdev: grvga: Fix CLUT register address offset in comment fbdev: sunxvr2500: replace printk with device-aware logging functions ...
2026-06-16Merge tag 'gpio-updates-for-v7.2-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux Pull gpio updates from Bartosz Golaszewski: "There's one new driver, one legacy driver removed, a kunit test-suite for the GPIO core, support for new models in existing drivers and a slew of various changes in many places though I can't think of anything controversial that would stand out - it's been a relatively calm cycle. GPIO core: - Add an initial set of kunit test cases for the GPIO subsystem - Use the devres owner as the GPIO chip's parent in absence of any other parent - Fix const-correctness of GPIO chip SRCU guards - Provide new GPIO consumer interfaces: gpiod_is_single_ended() and fwnode_gpiod_get() - Quarantine all legacy GPIO APIs in linux/gpio/legacy.h - Use __ro_after_init where applicable New drivers: - Add driver for the GPIO controller on Waveshare DSI TOUCH panels Removed drivers: - Remove the obsolete ts5500 GPIO driver Driver updates: - Modernize gpio-timberdale: remove platform data support and use generic device property accessors - Extend test build coverage by enabling COMPILE_TEST for more GPIO drivers - Add some missing dependencies in Kconfig - Add support for sparse fixed direction to gpio-regmap - Remove dead code from gpio-nomadik - use BIT() in gpio-mxc - use bitmap_complement() in gpio-xilinx and gpio-pca953x - Use more appropriate printing functions where applicable - Use named initializers for platform_device_id and i2c_device_id arrays - Convert gpio-altera to using the generic GPIO chip helper library - Add support for new models to gpio-dwapb, gpio-zynq, gpio-usbio and gpio-tegra186 - Unify the naming convention for Qualcomm in GPIO drivers - Fix interrupt bank mapping to GPIO chips in gpio-mt7621 - Add support for the lines-initial-states property to gpio-74x164 - Switch to using dynamic GPIO base in gpio-ixp4xx - Move the handling of an OF quirk from ASoC to gpiolib-of.c where other such quirks live - Use handle_bad_irq() in gpio-ep93xx - Some other minor tweaks and refactorings Devicetree bindings: - Document the Waveshare GPIO controller for DSI TOUCH panels - Document new models: Tegra238 in gpio-tegra186 and EIO GPIO in gpio-zynq - Add new properties for gpio-dwapb and fairchild,74hc595 - Fix whitespace issues - Sort compatibles alphabetically in gpio-zynq Documentation: - Fix kerneldoc warnings in gpio-realtek-otto Misc: - Attach software nodes representing GPIO chips to the actual struct device objects associated with them in some legacy platforms enabling real firmware node lookup instead of string matching - Drop unneeded dependencies on OF_GPIO from bus and staging drivers" * tag 'gpio-updates-for-v7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (62 commits) gpio: nomadik: remove dead DB8540 code from <gpio/gpio-nomadik.h> gpio: mt7621: fix interrupt banks mapping on gpio chips bus: ts-nbus: drop unneeded dependency on OF_GPIO staging: media: max96712: drop unneeded dependency on OF_GPIO gpiolib: Replace strcpy() with memcpy() gpio: remove obsolete UAF FIXMEs from lookup paths gpio: core: fix const-correctness of gpio_chip_guard gpio: mxc: use BIT() macro gpio: realtek-otto: fix kernel-doc warnings gpio: max77620: Unify usage of space and comma in platform_device_id array gpio: Use named initializers for platform_device_id arrays gpio: cros-ec: Drop unused assignment of platform_device_id driver data ARM: omap1: enable real software node lookup of GPIOs on Nokia 770 ARM: omap1: use platform_device_register_full() for GPIO devices on OMAP 16xx ARM: omap1: drop unused variable from omap16xx_gpio_init() gpio: gpiolib: use seq_puts() for plain strings gpio: ts5500: remove obsolete driver gpio: add kunit test cases for the GPIO subsystem kunit: provide kunit_platform_device_unregister() kunit: provide kunit_platform_device_register_full() ...
2026-06-15Merge tag 'objtool-core-2026-06-14' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - A large series of KLP fixes and improvements, in preparation of the arm64 port (Josh Poimboeuf) - Fix a number of bugs and issues on specific distro, LTO, FineIBT and kCFI configs (Josh Poimboeuf) - Misc other fixes by Josh Poimboeuf and Joe Lawrence * tag 'objtool-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (53 commits) objtool/klp: Cache dont_correlate() result objtool: Improve and simplify prefix symbol detection objtool/klp: Fix kCFI prefix finding/cloning objtool: Grow __cfi_* prefix symbols for all CFI+CALL_PADDING objtool/klp: Fix position-dependent checksums for non-relocated jumps/calls objtool: Add insn_sym() helper objtool/klp: Add correlation debugging output objtool/klp: Rewrite symbol correlation algorithm objtool/klp: Calculate object checksums klp-build: Validate short-circuit prerequisites objtool/klp: Remove "objtool --checksum" klp-build: Use "objtool klp checksum" subcommand objtool/klp: Add "objtool klp checksum" subcommand objtool: Consolidate file decoding into decode_file() objtool/klp: Extricate checksum calculation from validate_branch() objtool: Add is_cold_func() helper objtool: Add is_alias_sym() helper objtool/klp: Handle Clang .data..Lanon anonymous data sections objtool/klp: Create empty checksum sections for function-less object files objtool: Include libsubcmd headers directly from source tree ...
2026-06-15Merge tag 'locking-core-2026-06-14' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "Futex updates: - Optimize futex hash bucket access patterns (Peter Zijlstra) - Large series to address the robust futex unlock race for real, by Thomas Gleixner: "The robust futex unlock mechanism is racy in respect to the clearing of the robust_list_head::list_op_pending pointer because unlock and clearing the pointer are not atomic. The race window is between the unlock and clearing the pending op pointer. If the task is forced to exit in this window, exit will access a potentially invalid pending op pointer when cleaning up the robust list. That happens if another task manages to unmap the object containing the lock before the cleanup, which results in an UAF. In the worst case this UAF can lead to memory corruption when unrelated content has been mapped to the same address by the time the access happens. User space can't solve this problem without help from the kernel. This series provides the kernel side infrastructure to help it along: 1) Combined unlock, pointer clearing, wake-up for the contended case 2) VDSO based unlock and pointer clearing helpers with a fix-up function in the kernel when user space was interrupted within the critical section. ... with help by André Almeida: - Add a note about robust list race condition (André Almeida) - Add self-tests for robust release operations (André Almeida) Context analysis updates: - Implement context analysis for 'struct rt_mutex'. (Bart Van Assche) - Bump required Clang version to 23 (Marco Elver) Guard infrastructure updates: - Series to remove NULL check from unconditional guards (Dmitry Ilvokhin) Lockdep updates: - Restore self-test migrate_disable() and sched_rt_mutex state on PREEMPT_RT (Karl Mehltretter) Membarriers updates: - Use per-CPU mutexes for targeted commands (Aniket Gattani) - Modernize membarrier_global_expedited with cleanup guards (Aniket Gattani) - Add rseq stress test for CFS throttle interactions (Aniket Gattani) percpu-rwsems updates: - Extract __percpu_up_read() to optimize inlining overhead (Dmitry Ilvokhin) Seqlocks updates: - Allow UBSAN_ALIGNMENT to fail optimizing (Heiko Carstens) Lock tracing: - Add contended_release tracepoint to sleepable locks such as mutexes, percpu-rwsems, rtmutexes, rwsems and semaphores (Dmitry Ilvokhin) MAINTAINERS updates: - MAINTAINERS: Add RUST [SYNC] entry (Boqun Feng) Misc updates and fixes by Randy Dunlap, YE WEI-HONG, Fabricio Parra, Dmitry Ilvokhin and Peter Zijlstra" * tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (36 commits) locking: Add contended_release tracepoint to sleepable locks locking/percpu-rwsem: Extract __percpu_up_read() tracing/lock: Remove unnecessary linux/sched.h include futex: Optimize futex hash bucket access patterns rust: sync: completion: Mark inline complete_all and wait_for_completion MAINTAINERS: Add RUST [SYNC] entry cleanup: Specify nonnull argument index selftests: futex: Add tests for robust release operations Documentation: futex: Add a note about robust list race condition x86/vdso: Implement __vdso_futex_robust_try_unlock() x86/vdso: Prepare for robust futex unlock support futex: Provide infrastructure to plug the non contended robust futex unlock race futex: Add robust futex unlock IP range futex: Add support for unlocking robust futexes futex: Cleanup UAPI defines x86: Select ARCH_MEMORY_ORDER_TSO uaccess: Provide unsafe_atomic_store_release_user() futex: Provide UABI defines for robust list entry modifiers futex: Move futex related mm_struct data into a struct futex: Make futex_mm_init() void ...
2026-06-15Merge tag 'timers-vdso-2026-06-13' of ↵Linus Torvalds
gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip Pull vdso updates from Thomas Gleixner: - Remove the redundant CONFIG_GENERIC_TIME_VSYSCALL after converting the remaining users over. - Rework and sanitize the MIPS VDSO handling, so it does not handle the time related VDSO if there is no VDSO capable clocksource available. Also stop mapping VDSO data pages unconditionally even if there is no usage possible. * tag 'timers-vdso-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: MIPS: VDSO: Fold MIPS_CLOCK_VSYSCALL into MIPS_GENERIC_GETTIMEOFDAY MIPS: VDSO: Gate microMIPS restriction on GCC version MIPS: VDSO: Fold MIPS_DISABLE_VDSO into MIPS_GENERIC_GETTIMEOFDAY clocksource/drivers/mips-gic-timer: Only use VDSO_CLOCKMODE_GIC when it is a available MIPS: csrc-r4k: Only use VDSO_CLOCKMODE_R4K when it is a available MIPS: VDSO: Only map the data pages when the vDSO is used MIPS: Introduce Kconfig MIPS_GENERIC_GETTIMEOFDAY vdso/datastore: Always provide symbol declarations MAINTAINERS: Add include/linux/vdso_datastore.h to vDSO block vdso/gettimeofday: Rename __arch_get_vdso_u_timens_data() vdso/treewide: Drop GENERIC_TIME_VSYSCALL vdso/vsyscall: Gate update_vsyscall() behind CONFIG_GENERIC_GETTIMEOFDAY riscv: vdso: Drop CONFIG_GENERIC_TIME_VSYSCALL guard around syscall fallbacks
2026-06-15Merge tag 'vfs-7.2-rc1.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "Features: - Reduce pipe->mutex contention by pre-allocating pages outside the lock in anon_pipe_write(). anon_pipe_write() called alloc_page() once per page while holding pipe->mutex. The allocation can sleep doing direct reclaim and runs memcg charging, which extends the critical section and stalls any concurrent reader on the same mutex. Now up to 8 pages are pre-allocated before the mutex is taken, leftovers are recycled into the per-pipe tmp_page[] cache before unlock, and any remainder is released after unlock, keeping the allocator out of the critical section on both sides. On a writers x readers sweep with 64KB writes against a 1 MB pipe throughput improves 6-28% and average write latency drops 5-22%; under memory pressure - when the cost of holding the mutex across reclaim is highest - throughput improves 21-48% and latency drops 17-33%. The microbenchmark is added to selftests. - uaccess/sockptr: fix the ignored_trailing logic in copy_struct_to_user() to behave as documented and the usize check in copy_struct_from_sockptr() for user pointers, and add copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr() helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC). - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real inode backing a dentry via d_real_inode(). On overlayfs the inode attached to the dentry doesn't carry the underlying device information; this is used by the filesystem restriction BPF program that was merged into systemd. - docs: add guidelines for submitting new filesystems, motivated by the maintenance burden abandoned and untestable filesystems impose on VFS developers, blocking infrastructure work like folio conversions and iomap migration. Fixes: - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() and drop the now-redundant assignments in callers. This began as a one-line dma-buf fix for a path_noexec() warning; a pseudo filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo() callers were audited: the only visible effect is on dma-buf where SB_I_NOEXEC silences the warning. - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs, qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a device with a sector size > PAGE_SIZE crashed roughly half of them; the rest had the same missing error handling pattern. Plus a follow-up releasing the superblock buffer_head when setting the minix v3 block size fails. - mount: honour SB_NOUSER in the new mount API. - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by switching the process-group paths of send_sigio() and send_sigurg() from read_lock(&tasklist_lock) to RCU, matching the single-PID path. - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing delegated NFS mounts (fsopen() in a container with the mount performed by a privileged daemon) that broke when non-init s_user_ns was tied to FS_USERNS_MOUNT. - selftests/namespaces: fix a hang in nsid_test where an unreaped grandchild kept the TAP pipe write-end open, a waitpid(-1) race in listns_efault_test, and a false FAIL on kernels without listns() where the tests should SKIP. - filelock: fix the break_lease() stub signature for CONFIG_FILE_LOCKING=n. - init/initramfs_test: wait for the async initramfs unpacking before running; the test and do_populate_rootfs() share the parser state. - fs/coredump: reduce redundant log noise in validate_coredump_safety(). - iomap: pass the correct length to fserror_report_io() in __iomap_write_begin(). - backing-file: fix the backing_file_open() kerneldoc. Cleanups: - initramfs: refactor the cpio hex header parsing to use hex2bin() instead of the hand-rolled simple_strntoul() which is reverted, and extend the initramfs KUnit tests to cover header fields with 0x prefixes. - Replace __get_free_pages() and friends with kmalloc()/kzalloc() across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2, isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the do_mounts init code - part of the larger work of replacing page allocator calls with kmalloc(). - Use clear_and_wake_up_bit() in unlock_buffer() and journal_end_buffer_io_sync() instead of open-coding the sequence. - Drop unused VFS exports: unexport drop_super_exclusive(), remove start_removing_user_path_at(), and fold __start_removing_path() into start_removing_path(). - fs/read_write: narrow the __kernel_write() export with EXPORT_SYMBOL_FOR_MODULES(). - vfs: uapi: retire octal and hex constants in favor of (1 << n) for the O_ flags. Finding a free bit for a new flag across the architectures was needlessly hard with the mixed bases. - dcache: add extra sanity checks of dead dentries in dentry_free() via a new DENTRY_WARN_ONCE() that also prints d_flags. - iov_iter: use kmemdup_array() in dup_iter() to harden the allocation against multiplication overflow. - fs/pipe: write to ->poll_usage only once. - vfs: remove an always-taken if-branch in find_next_fd(). - dcache: use kmalloc_flex() for struct external_name in __d_alloc(). - namei: use QSTR() instead of QSTR_INIT() in path_pts(). - sync_file_range: delete dead S_ISLNK code. - Comment fixes: retire a stale comment in fget_task_next() and fix assorted spelling mistakes" * tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits) backing-file: fix backing_file_open() kerneldoc parameter iomap: pass the correct len to fserror_report_io in __iomap_write_begin vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags bpf: add bpf_real_inode() kfunc fs/read_write: Do not export __kernel_write() to the entire world libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo() mount: honour SB_NOUSER in the new mount API fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling selftests/pipe: add pipe_bench microbenchmark fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write fs: retire stale comment in fget_task_next() fs: fix spelling mistakes in comment bfs: replace get_zeroed_page() with kzalloc() binfmt_misc: replace __get_free_page() with kmalloc() configfs: replace __get_free_pages() with kzalloc() fs/namespace: use __getname() to allocate mntpath buffer fs/select: replace __get_free_page() with kmalloc() ...
2026-06-15Merge tag 'kernel-7.2-rc1.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc kernel updates from Christian Brauner: "Fixes - rhashtable: give each instance its own lockdep class syzbot reported a circular locking dependency between ht->mutex and fs_reclaim via the simple_xattrs rhashtable being torn down during inode eviction. The predicted deadlock cannot occur: rhashtable_free_and_destroy() cancels the deferred worker before taking ht->mutex and acquisitions on distinct rhashtables are on distinct mutexes. Lockdep flags a cycle anyway because every ht->mutex in the kernel shared the single static lockdep class from rhashtable_init_noprof(). The lockdep key is lifted to a per-call-site static key so every rhashtable instance gets its own class. - selftests/clone3: fix misuse of the libcap library interface in the cap_checkpoint_restore test and remove unused variables - selftests/pid_namespace: compute the pid_max test limits dynamically instead of hardcoding values below the kernel-enforced minimum of PIDS_PER_CPU_MIN * num_possible_cpus() which made the tests fail on machines with many possible CPUs - selftests: fix the Makefile TARGETS entry for nsfs which wasn't adjusted when the tests moved under filesystems/ Cleanups - ipc/sem.c: use unsigned int for nsops to match the declaration in syscalls.h" * tag 'kernel-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: selftests/clone3: remove unused variables selftests/clone3: fix libcap interface usage ipc/sem.c: use unsigned int for nsops selftests: Fix Makefile target for nsfs rhashtable: give each instance its own lockdep class selftests/pid_namespace: compute pid_max test limits dynamically
2026-06-13Merge tag 'core-urgent-2026-06-13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull debugobjects fix from Ingo Molnar: - Fix potential debugobjects deadlock on PREEMPT_RT kernels (Waiman Long) * tag 'core-urgent-2026-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: debugobjects: Don't call fill_pool() in early boot hardirq context
2026-06-12vsprintf: Add upper case flavour to %p[mM]Andy Shevchenko
Some of the (ABI aware) code needs an upper case when printing MAC addresses. Introduce an extension for that into the existing %p[mM]. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Link: https://patch.msgid.link/20260603104351.152085-2-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek <pmladek@suse.com>
2026-06-11lib/crypto: gf128hash: mark clmul32() as noinline_for_stackArnd Bergmann
During randconfig testing, I came across a lot of warnings for the newly added carryless multiplication function triggering excessive stack usage from spilling temporary variables to the stack: lib/crypto/gf128hash.c:166:1: error: stack frame size (1192) exceeds limit (1024) in 'polyval_mul_generic' [-Werror,-Wframe-larger-than] In addition to the possible risk of overflowing the kernel stack, the generated object code surely performs very poorly. This only happens on architectures that don't provide uint128_t (which should be all 32-bit architectures on modern compilers), but though I tested random x86 and arm configs, I only saw this with arm's CONFIG_THUMB2_KERNEL, which adds more pressure to the register allocator. The testing was done using clang-22, I don't know if gcc has the same problem. Marking clmul32() as noinline_for_stack experimentally shows all of the affected builds to completely solve the problem, reducing the stack usage to a few bytes as expected. Since u64 arithmetic frequently leads to compilers badly optimizing 32-bit targets, keeping clmul32 out of line is likely to help on other 32-bit configurations as well when they run into this problem, though it may also result in a small performance degradation in configurations that would benefit from inlining. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Link: https://patch.msgid.link/20260611125952.3387258-1-arnd@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org>
2026-06-11lib/test_firmware: allocate the configured into_buf sizeSamuel Moelius
The batched into_buf test path allocates TEST_FIRMWARE_BUF_SIZE bytes unconditionally, but then passes test_fw_config->buf_size to request_firmware_into_buf() or request_partial_firmware_into_buf(). Userspace can set config_buf_size above TEST_FIRMWARE_BUF_SIZE before triggering a batched request. If the firmware file is large enough, the firmware loader writes past the end of the 1 KiB test buffer. Allocate the buffer with the same size that the test passes to the firmware API so config_buf_size remains the actual buffer size under test. Assisted-by: Codex:gpt-5.5-cyber-preview Link: https://lore.kernel.org/20260605003038.2005840-1-sam.moelius@trailofbits.com Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <kees@kernel.org> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Scott Branden <scott.branden@broadcom.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-09fbdev/arm: Export acorndata_8x8 font symbol for bootloaderHelge Deller
The text display code used in the Risc PC kernel image decompression code uses arch/arm/boot/compressed/font.c, which includes lib/fonts/font_acorn_8x8.c, which further includes <linux/font.h>. Since commit 97df8960240a ("lib/fonts: Provide helpers for calculating glyph pitch and size") <linux/font.h> contains inline functions that require __do_div64, which is not linked into the ARM kernel decompressor. This makes Risc PC zImages fail to build. Resolve this issue by defining the BOOTLOADER symbol and use it to avoid a static declaration of the acorndata_8x8 symbol. That way it can be referenced by the arm bootloader, and other static math functions and symbols (like __do_div64) stay static and don't get unneccesary included in the ARM kernel bootloader decompressor object file. Fixes: 97df8960240a ("lib/fonts: Provide helpers for calculating glyph pitch and size") Reported-by: Ethan Nelson-Moore <enelsonmoore@gmail.com> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Cc: linux-arm-kernel@lists.infradead.org Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Helge Deller <deller@gmx.de>
2026-06-08lib/test_hmm: check alloc_page_vma() return value and handle OOMQiang Liu
Check alloc_page_vma() return status for page allocation failures, free allocated pages and return VM_FAULT_OOM on error. Handle return codes of dmirror_devmem_fault_alloc_and_copy(), call migrate_vma_finalize() to remove migration entries from migrate_vma_setup(). Link: https://lore.kernel.org/20260521021858.21511-1-liuqiangneo@163.com Signed-off-by: Qiang Liu <liuqiang@kylinos.cn> Cc: Alistair Popple <apopple@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Leon Romanovsky <leon@kernel.org> [akpm@linux-foundation.org: fix dmirror_devmem_fault_alloc_and_copy() retval handling] Link: https://lore.kernel.org/oe-kbuild-all/202606011329.zWs2BKy4-lkp@intel.com/ Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-08lib/test_hmm: fix memory leak in dmirror_migrate_to_system()Hao Ge
Move the kvcalloc() calls after the early return checks to avoid leaking src_pfns and dst_pfns when end < start or mmget_not_zero() fails. Link: https://lore.kernel.org/20260528011336.20797-1-hao.ge@linux.dev Fixes: 775465fd26a3 ("lib/test_hmm: add zone device private THP test infrastructure") Signed-off-by: Hao Ge <hao.ge@linux.dev> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reported-by: Sashiko <sashiko-bot@kernel.org> Reviewed-by: Balbir Singh <balbirs@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Leon Romanovsky <leon@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-07rhashtable: Fix rhashtable_next_key() build warningsMykyta Yatsenko
rhashtable.o builds with warnings as rhashtable_next_key() kdoc from lib/rhashtable.c does not have the arguments descriptions. Move rhashtable_next_key() kdoc from header to c file, matching other functions. Move rhashtable_next_key() next to the other forward declarations in the header file. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202606061925.WI4bYI8k-lkp@intel.com/ Fixes: 8f4fa9f89b72 ("rhashtable: Add rhashtable_next_key() API") Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20260606-rhash_fixes_1-v1-1-932ab036e6bc@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-06debugobjects: Don't call fill_pool() in early boot hardirq contextWaiman Long
When booting a debug PREEMPT_RT kernel on an ARM64 system, a "inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage" lockdep warning message was reported to the console. During early boot, interrupts are enabled before the scheduler is enabled. In this window (before SYSTEM_SCHEDULING is set) interrupts can fire and in the hard interrupt context handler attempt to fill the pool This can lead to a deadlock when the interrupt occurred when the interrupt hits a region which holds a lock that is required to be taken in the allocation path. Add a new can_fill_pool() helper and reorder the exception rule and forbid this scenario by excluding allocations from hard interrupt context. Fixes: 06e0ae988f6e ("debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING") Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260605173038.495075-1-longman@redhat.com
2026-06-05rhashtable: Add selftest for rhashtable_next_key()Mykyta Yatsenko
Insert n elements, then verify: - NULL prev_key walks from the beginning, visiting all n - non-existing prev_key returns ERR_PTR(-ENOENT) Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Link: https://lore.kernel.org/r/20260605-rhash-v7-2-5b8e05f8630d@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05rhashtable: Add rhashtable_next_key() APIMykyta Yatsenko
Introduce a simpler iteration mechanism for rhashtable that lets the caller continue from an arbitrary position by supplying the previous key, without the per-iterator state of the rhashtable_walk_* API. void *rhashtable_next_key(struct rhashtable *ht, const void *prev_key); Caller holds RCU; passes NULL prev_key for the first element or the previously returned key to advance. Walks tbl->future_tbl chain so in-flight rehashes are observed. Best-effort: in case of concurrent resize, provides no guarantees: - may produce duplicate elements - may skip any amount of elements - termination of the loop is not guaranteed in case of sustained rehash. Callers are advised to bound loop externally or avoid inserting new elements during such loop. Returns ERR_PTR(-ENOENT) if prev_key is not found. Behavior on tables with duplicate keys is undefined. rhltable is not supported — returns ERR_PTR(-EOPNOTSUPP). Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Link: https://lore.kernel.org/r/20260605-rhash-v7-1-5b8e05f8630d@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-04raid6: use kmalloc() in raid6_select_algo()Mike Rapoport (Microsoft)
raid6_select_algo() allocates 8 pages for buffer that is used as a scratch area for selection of the best algorithm. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API than ancient __get_free_pages(). kmalloc() does not require ugly casts and kfree() does not need to know the size of the freed object. There is no performance difference because kmalloc() redirects allocations of such size to the page allocator. Replace __get_free_pages() call with kmalloc(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Link: https://lore.kernel.org/20260528-lib-v4-2-4e3ad1277279@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@kernel.org> Cc: Li Nan <linan122@huawei.com> Cc: Song Liu <song@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-04xor: use kmalloc() in calibrate_xor_blocks()Mike Rapoport (Microsoft)
Patch series "lib/raid: replace __get_free_pages() call with kmalloc()", v4. The xor benchmark allocates 4 pages for a scratch buffer that is used purely as a CPU-only XOR working area. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API than ancient __get_free_pages(). kmalloc() does not require ugly casts and kfree() does not need to know the size of the freed object. There is no performance difference because kmalloc() redirects allocations of such size to the page allocator. Replace __get_free_pages() call with kmalloc(). This patch (of 2): The xor benchmark allocates 4 pages for a scratch buffer that is used purely as a CPU-only XOR working area. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API than ancient __get_free_pages(). kmalloc() does not require ugly casts and kfree() does not need to know the size of the freed object. There is no performance difference because kmalloc() redirects allocations of such size to the page allocator. Replace __get_free_pages() call with kmalloc(). Link: https://lore.kernel.org/20260528-lib-v4-0-4e3ad1277279@kernel.org Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Link: https://lore.kernel.org/20260528-lib-v4-1-4e3ad1277279@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Hannes Reinecke <hare@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Li Nan <linan122@huawei.com> Cc: Song Liu <song@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-04lib: kunit_iov_iter: repeatedly call alloc_pages_bulk()Thomas Weißschuh
alloc_pages_bulk() is not guaranteed to return all requested pages in a single call. Call it repeatedly until all pages have been allocated or no more progress is being made. Link: https://lore.kernel.org/20260526-kunit_iov_iter-alloc_bulk-v2-1-24fbcd995c61@weissschuh.net Fixes: 2d71340ff1d4 ("iov_iter: Kunit tests for copying to/from an iterator") Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Cc: "Christian A. Ehrhardt" <lk@c--e.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-04vdso/gettimeofday: Rename __arch_get_vdso_u_timens_data()Thomas Weißschuh
Originally this function was supposed to work the same way as __arch_get_vdso_u_time_data() and be overridden on some architectures. However the actually used implementation, which just adds PAGE_SIZE, does not need this override mechanism. Adjust the name to reflect the true nature of the function. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260519-vdso-arch_get_vdso_u_timens_data-v1-1-43f0d62716e8@linutronix.de
2026-06-04lib/fonts: Look up glyph data with font_data_glyph_buf()Thomas Zimmermann
Add font_data_glyph_buf() to retrieve a character's glyph data or NULL otherwise. Console fonts can currently contain 256 or 512 glyphs. The kernel-internal characters are of type char, unsigned short or unsigned int. Catch all of them by accepting unsigned int. Callers possibly have to cast from signed to unsigned types to reach all glyphs in a font. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://patch.msgid.link/20260529140759.529929-2-tzimmermann@suse.de
2026-06-03mm/slab: improve kmem_cache_alloc_bulkChristoph Hellwig
The kmem_cache_alloc_bulk return value is weird. It returns the number of allocated objects, but that must always be 0 or the requested number based on the implementations and the handling in the callers, but that assumption is not actually documented anywhere, which confuses automated review tools. Fix this by returning a bool if the allocation succeeded and adding a kerneldoc comment explaining the API. [rob.clark@oss.qualcomm.com: fixups in msm_iommu_pagetable_prealloc_allocate() ] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com> # skbuff Link: https://patch.msgid.link/20260528093437.2519248-2-hch@lst.de Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
2026-06-03lib/vsprintf: replace min_t/max_t with min/maxThorsten Blum
Use the simpler min()/max() macros since the values are all compatible. Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Link: https://patch.msgid.link/20260518123145.79411-3-thorsten.blum@linux.dev Signed-off-by: Petr Mladek <pmladek@suse.com>
2026-06-03lockdep/selftests: Restore sched_rt_mutex state on PREEMPT_RTKarl Mehltretter
The WW-mutex selftests deliberately exercise failing lock paths. On PREEMPT_RT, some of those paths enter the RT-mutex scheduler helpers. The change referenced by the Fixes tag made those helpers track RT-mutex scheduling state in current->sched_rt_mutex. The bit is normally cleared by the matching post-schedule helper, but some WW-mutex selftests disable the runtime debug_locks flag before that happens. With debug_locks cleared, lockdep_assert() does not evaluate the expression that clears the bit, leaving stale state for the next testcase. With CONFIG_PREEMPT_RT=y and CONFIG_DEBUG_LOCKING_API_SELFTESTS=y, that stale state produces warnings such as: WARNING: kernel/sched/core.c:7557 at rt_mutex_pre_schedule+0x26/0x2d RIP: 0010:rt_mutex_pre_schedule+0x26/0x2d Save and restore current->sched_rt_mutex around each testcase, matching the existing PREEMPT_RT cleanup for task-local migration and RCU state. Fixes: d14f9e930b90 ("locking/rtmutex: Use rt_mutex specific scheduler helpers") Assisted-by: Codex:gpt-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20260523185123.17482-3-kmehltretter@gmail.com
2026-06-03lockdep/selftests: Restore migrate_disable() state on PREEMPT_RTKarl Mehltretter
The lockdep selftests deliberately run unbalanced locking patterns. dotest() restores the task state they leave behind before running the next testcase. On PREEMPT_RT, spin_lock() uses migrate_disable() instead of disabling preemption. dotest() cleans up the resulting migration-disabled state, but that cleanup is still guarded by CONFIG_SMP. That used to match the scheduler data model, where migration_disabled was also CONFIG_SMP-only. The commit referenced below made SMP scheduler state unconditional, so CONFIG_SMP=n PREEMPT_RT kernels with CONFIG_DEBUG_LOCKING_API_SELFTESTS=y report success from the selftests and then trip over stale current->migration_disabled state: releasing a pinned lock bad: scheduling from the idle thread! Kernel panic - not syncing: Fatal exception Save and restore current->migration_disabled for every PREEMPT_RT build. Fixes: cac5cefbade9 ("sched/smp: Make SMP unconditional") Assisted-by: Codex:gpt-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20260523185123.17482-2-kmehltretter@gmail.com
2026-06-02lib/test_vmalloc: add vrealloc test caseShivam Kalra
Introduce a new test case "vrealloc_test" that exercises the vrealloc() shrink and in-place grow paths: - Grow beyond allocated pages (triggers full reallocation). - Shrink crossing a page boundary (frees tail pages). - Shrink within the same page (no page freeing). - Grow within the already allocated page count (in-place). Data integrity is validated after each realloc step by checking that the first byte of the original allocation is preserved. The test is gated behind run_test_mask bit 12 (id 4096). Link: https://lore.kernel.org/20260519-vmalloc-shrink-v14-5-70b96ee3e9c9@zohomail.in Signed-off-by: Shivam Kalra <shivamkalra98@zohomail.in> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02lib/test_hmm: fix error path in dmirror_devmem_fault()Qiang Liu
Handle migrate_vma_setup() failure via goto err for unified cleanup. Link: https://lore.kernel.org/20260515070312.130435-1-liuqiangneo@163.com Signed-off-by: Qiang Liu <liuqiang@kylinos.cn> Reviewed-by: Alistair Popple <apopple@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Leon Romanovsky <leon@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02lib/test_hmm: use kvfree() to free kvcalloc() allocationsHao Ge
Coccinelle scripts/coccinelle/api/kfree_mismatch.cocci reports the following warnings: lib/test_hmm.c:1256:15-16: WARNING kvmalloc is used to allocate this memory at line 1191 lib/test_hmm.c:1257:15-16: WARNING kvmalloc is used to allocate this memory at line 1196 Fix this by replacing kfree() with kvfree() to correctly handle the vmalloc() fallback path of kvcalloc(). Link: https://lore.kernel.org/20260513082525.154036-1-hao.ge@linux.dev Fixes: 775465fd26a3 ("lib/test_hmm: add zone device private THP test infrastructure") Signed-off-by: Hao Ge <hao.ge@linux.dev> Acked-by: Balbir Singh <balbirs@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Leon Romanovsky <leon@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02lib/test_meminit: use && for boolsAlexander Potapenko
As pointed out by Dan Carpenter, test_kmemcache() was using a bitwise AND on two bools instead of a boolean AND. Fix this for the sake of code cleanliness. Link: https://lore.kernel.org/20260504100637.1535762-1-glider@google.com Fixes: 5015a300a522 ("lib: introduce test_meminit module") Signed-off-by: Alexander Potapenko <glider@google.com> Reported-by: Dan Carpenter <error27@gmail.com> Closes: https://lore.kernel.org/kernel-janitors/afOcIan1ap9kD26M@stanley.mountain/ Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02maple_tree: document that "last" in mtree_insert_range() is inclusiveSteven Rostedt
The kernel doc of mtree_insert_range() does not state if the address represented by the "last" parameter is inclusive or exclusive. This can lead to bugs by code that assumes it is exclusive. Explicitly state that the parameter is inclusive. Link: https://lore.kernel.org/20260512175623.4c5ca8d2@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: "Liam R. Howlett" <liam@infradead.org> Acked-by: SeongJae Park <sj@kernel.org> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andrew Ballance <andrewjballance@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-02vdso/datastore: Mark vdso_k_*_data pointers as __ro_after_initThomas Weißschuh
These pointers are only modified once in vdso_setup_data_pages(), during the init phase. Make them read-only after that. Drop __refdata as that would conflict with __ro_after_init. Modpost does accept the reference from a __ro_after_init symbol to an __init one. Fixes: 05988dba1179 ("vdso/datastore: Allocate data pages dynamically") Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260513-vdso-ro-after-init-v1-1-4b51f74015a4@linutronix.de
2026-06-01liveupdate: Reference count incoming FLB dataDavid Matlack
Increment the incoming FLB refcount in liveupdate_flb_get_incoming() so that the FLB structure cannot be freed while the caller is actively using it. Add an additional liveupdate_flb_put_incoming() function so the caller can explicitly indicate when it is done using the FLB data. During a Live Update, a subsystem might need to hold onto the incoming File-Lifecycle-Bound (FLB) data for an extended period, such as during device enumeration. Incrementing the reference count guarantees that the data remains valid and accessible until the subsystem releases it, preventing future use-after-free bugs. Fixes: cab056f2aae7 ("liveupdate: luo_flb: introduce File-Lifecycle-Bound global state") Signed-off-by: David Matlack <dmatlack@google.com> Reviewed-by: Samiullah Khawaja <skhawaja@google.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://lore.kernel.org/r/20260423174032.3140399-3-dmatlack@google.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-05-29Merge tag 'iommu-fixes-v7.1-rc5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux Pull iommu fixes from Joerg Roedel: - Fix compile warning with gcc-16.1 - Intel VT-d: Simplify calculate_psi_aligned_address() - MAINTAINERS updates * tag 'iommu-fixes-v7.1-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux: MAINTAINERS: Add my employer to my entries MAINTAINERS: Add Vasant Hegde to reviewers of AMD IOMMU iommu, debugobjects: avoid gcc-16.1 section mismatch warnings iommu/vt-d: Simplify calculate_psi_aligned_address()
2026-05-28lib/nmi_backtrace: print out the CPUs which fail to respond to NMIFeng Tang
When debugging RCU stall cases, usually all CPUs will respond to the NMI and print out the backtrace. But in some nasty or hardware related cases, some CPUs may fail to respond in 10 seconds, and very likely this is sign of severe issues. Paul McKenney has implemented the NMI backtrace stall check for x86, and for other architectures, it should be also helpful to at least print out those CPUs which failed to repond to the NMI, so that users can get an early heads-up for possible CPU hard stall. [feng.tang@linux.alibaba.com: avoid hard-coding "10" in two places and in a comment] Link: https://lore.kernel.org/ag-1ciG0FSomBf7q@U-2FWC9VHC-2323.local [akpm@linux-foundation.org: use __stringify()] Link: https://lore.kernel.org/20260521030336.92172-1-feng.tang@linux.alibaba.com Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28string: use min in sized_strscpyThorsten Blum
Use min() and drop the limit variable to simplify sized_strscpy(). Link: https://lore.kernel.org/20260514165601.527883-3-thorsten.blum@linux.dev Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Cc: Andy Shevchenko <andy@kernel.org> Cc: Kees Cook <kees@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28lib/uuid_kunit: add tests for the four random UUID/GUID generatorsStepan Ionichev
uuid_kunit currently exercises only guid_parse() and uuid_parse() (plus their invalid-input paths). The four random generators exported from lib/uuid.c -- generate_random_uuid(), generate_random_guid(), uuid_gen() and guid_gen() -- have no direct kunit coverage. Random output cannot be compared against a fixed expected value, but RFC 4122 section 4.4 specifies two invariants that any version-4 random UUID/GUID must satisfy: - version 4 in the high nibble of the version byte (byte 6 in the wire uuid_t layout, byte 7 in the byte-swapped guid_t layout); - variant DCE 1.1 (binary 10x) in the high bits of byte 8. Add four test cases that invoke each generator several times and verify these bit patterns hold. The same checks catch a regression in either the mask/OR sequence in the generators or the layout constants. Run the loop a handful of times to cover the small but non-zero chance that an unmasked random byte happens to satisfy the version/variant pattern by accident on a single call. Link: https://lore.kernel.org/20260516120915.40544-1-sozdayvek@gmail.com Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Gow <david@davidgow.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28error-inject: use IS_ERR() check for debugfs_create_file()Ingyu Jang
debugfs_create_file() returns an error pointer on failure, never NULL, so the !file check in ei_debugfs_init() never triggers and the debugfs_remove() cleanup cannot run. Use IS_ERR() and propagate the actual error via PTR_ERR(). Link: https://lore.kernel.org/20260514193214.2432769-1-ingyujang25@korea.ac.kr Signed-off-by: Ingyu Jang <ingyujang25@korea.ac.kr> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6_kunit: randomize buffer alignmentChristoph Hellwig
Add code to add random alignment to the buffers to test the case where they are not page aligned, and to move the buffers to the end of the allocation so that they are next to the vmalloc guard page. This does not include the recovery buffers as the recovery requires page alignment. Link: https://lore.kernel.org/20260518051804.462141-19-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6_kunit: randomize parameters and increase limitsChristoph Hellwig
The current test has double-quadratic behavior in the selection for the updated ("XORed") disks, and in the selection of updated pointers, which makes scaling it to more tests difficult. At the same time it only ever tests with the maximum number of disks, which leaves a coverage hole for smaller ones. Fix this by randomizing the total number, failed disks and regions to update, and increasing the upper number of tests disks. Link: https://lore.kernel.org/20260518051804.462141-18-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6_kunit: cleanup dataptr handlingChristoph Hellwig
Move the global dataptr array into test_recover() as all sites that fill data or parity can use test_buffers directly, and this localized the override for the failed slots to the recovery testing routine. Link: https://lore.kernel.org/20260518051804.462141-17-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6_kunit: dynamically allocate data buffers using vmallocChristoph Hellwig
Use vmalloc for the data buffers instead of using static .data allocations. This provides for better out of bounds checking and avoids wasting kernel memory after the test has run. vmalloc is used instead of kmalloc to provide for better out of bounds access checking as in other kunit tests. Link: https://lore.kernel.org/20260518051804.462141-16-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6_kunit: use KUNIT_CASE_PARAMChristoph Hellwig
The raid6 test combines various generation and recovery algorithms. Use KUNIT_CASE_PARAM and provide a generator that iterates over the possible combinations instead of looping inside a single test instance. Link: https://lore.kernel.org/20260518051804.462141-15-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6: update top of file commentsChristoph Hellwig
Drop the pointless mention of the file name, and use standard formatting for the top of file comments. Link: https://lore.kernel.org/20260518051804.462141-14-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6: use static_call for raid6_recov_2data and raid6_recov_datapChristoph Hellwig
Avoid expensive indirect calls for the recovery routines as well. Link: https://lore.kernel.org/20260518051804.462141-13-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6: use static_call for gen_syndrom and xor_syndromChristoph Hellwig
Avoid indirect calls for P/Q parity generation. Link: https://lore.kernel.org/20260518051804.462141-12-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6: rework registration of optimized algorithmsChristoph Hellwig
Replace the static array of algorithms with a call to an architecture helper to register algorithms. This serves two purposes: it avoid having to register all algorithms in a single central place, and it removes the need for the priority field by just registering the algorithms that the architecture considers suitable for the currently running CPUs. [hch@lst.de: register avx512 after avx2] Link: https://lore.kernel.org/20260527074539.2292913-3-hch@lst.de Link: https://lore.kernel.org/20260518051804.462141-11-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6: hide internalsChristoph Hellwig
Split out two new headers from the public pq.h: - lib/raid/raid6/algos.h contains the algorithm lists private to lib/raid/raid6 - include/linux/raid/pq_tables.h contains the tables also used by async_tx providers. The public include/linux/pq.h is now limited to the public interface for the consumers of the RAID6 PQ API. [hch@lst.de: remove duplicate ccflags-y line] Link: https://lore.kernel.org/20260527074539.2292913-2-hch@lst.de Link: https://lore.kernel.org/20260518051804.462141-10-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-05-28raid6: warn when using less than four devicesChristoph Hellwig
Quoting H. Peter Anvin who came up with the RAID6 P/Q algorithm, and who wrote the initial implementation, then still part of the md driver: The RAID-6 code has *never* supported only 3 units, and if it ever worked for *any* of the implementations it was purely by accident. Speaking as the original author I should know; this was deliberate as in some cases the degenerate case (3) would have required extra trays in the code to no user benefit. While md never allowed less than 4 devices, btrfs does. This new warning will trigger for such file systems, but given how it already causes havoc that is a good thing. If btrfs wants to fix third, it should switch to transparently use three-way mirroring underneath, which will work as P and Q are copies of the single data device by the definition of the Linux RAID 6 P/Q algorithm. Link: https://lore.kernel.org/20260518051804.462141-9-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64 Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>