kernel/linux.git/arch/um/include, branch v6.18.34

ring-buffer: Flush and stop persistent ring buffer on panic

2026-06-01T15:50:44+00:00

commit a494d3c8d5392bcdff83c2a593df0c160ff9f322 upstream. On real hardware, panic and machine reboot may not flush hardware cache to memory. This means the persistent ring buffer, which relies on a coherent state of memory, may not have its events written to the buffer and they may be lost. Moreover, there may be inconsistency with the counters which are used for validation of the integrity of the persistent ring buffer which may cause all data to be discarded. To avoid this issue, stop recording of the ring buffer on panic and flush the cache of the ring buffer's memory. Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Cc: stable@vger.kernel.org Cc: Will Deacon Cc: Mathieu Desnoyers Cc: Ian Rogers Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) Acked-by: Catalin Marinas Acked-by: Geert Uytterhoeven Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

um: Disable KASAN_INLINE when STATIC_LINK is selected

2025-12-18T13:03:29+00:00

[ Upstream commit a3209bb94b36351f11e0d9e72ac44e5dd777a069 ] um doesn't support KASAN_INLINE together with STATIC_LINK. Instead of failing the build, disable KASAN_INLINE when STATIC_LINK is selected. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202511290451.x9GZVJ1l-lkp@intel.com/ Fixes: 1e338f4d99e6 ("kasan: introduce ARCH_DEFER_KASAN and unify static key across modes") Signed-off-by: Christophe Leroy (CS GROUP) Link: https://patch.msgid.link/2620ab0bbba640b6237c50b9c0dca1c7d1142f5d.1764410067.git.chleroy@kernel.org Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

Merge tag 'uml-for-linux-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2025-10-06T19:10:55+00:00

Pull uml updates from Johannes Berg: - minor preparations for SMP support - SPARSE_IRQ support for kunit - help output cleanups * tag 'uml-for-linux-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Remove unused ipi_pipe field from cpuinfo_um um: Remove unused cpu_data and current_cpu_data macros um: Stop tracking virtual CPUs via mm_cpumask() um: Centralize stub size calculations um: Remove outdated comment about STUB_DATA_PAGES um: Remove unused offset and child_err fields from stub_data um: Indent time-travel help messages um: Fix help message for ssl-non-raw um: vector: Fix indentation for help message um: Add missing trailing newline to help messages um: virtio-pci: implement .shutdown() um: Support SPARSE_IRQ

kasan: introduce ARCH_DEFER_KASAN and unify static key across modes

2025-09-21T21:21:58+00:00

Patch series "kasan: unify kasan_enabled() and remove arch-specific implementations", v6. This patch series addresses the fragmentation in KASAN initialization across architectures by introducing a unified approach that eliminates duplicate static keys and arch-specific kasan_arch_is_ready() implementations. The core issue is that different architectures have inconsistent approaches to KASAN readiness tracking: - PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready() - Only HW_TAGS mode had a unified static key (kasan_flag_enabled) - Generic and SW_TAGS modes relied on arch-specific solutions or always-on behavior This patch (of 2): Introduce CONFIG_ARCH_DEFER_KASAN to identify architectures [1] that need to defer KASAN initialization until shadow memory is properly set up, and unify the static key infrastructure across all KASAN modes. [1] PowerPC, UML, LoongArch selects ARCH_DEFER_KASAN. The core issue is that different architectures haveinconsistent approaches to KASAN readiness tracking: - PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready() - Only HW_TAGS mode had a unified static key (kasan_flag_enabled) - Generic and SW_TAGS modes relied on arch-specific solutions or always-on behavior This patch addresses the fragmentation in KASAN initialization across architectures by introducing a unified approach that eliminates duplicate static keys and arch-specific kasan_arch_is_ready() implementations. Let's replace kasan_arch_is_ready() with existing kasan_enabled() check, which examines the static key being enabled if arch selects ARCH_DEFER_KASAN or has HW_TAGS mode support. For other arch, kasan_enabled() checks the enablement during compile time. Now KASAN users can use a single kasan_enabled() check everywhere. Link: https://lkml.kernel.org/r/20250810125746.1105476-1-snovitoll@gmail.com Link: https://lkml.kernel.org/r/20250810125746.1105476-2-snovitoll@gmail.com Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049 Signed-off-by: Sabyrzhan Tasbolatov Reviewed-by: Christophe Leroy Reviewed-by: Ritesh Harjani (IBM) #powerpc Cc: Alexander Gordeev Cc: Alexander Potapenko Cc: Alexandre Ghiti Cc: Alexandre Ghiti Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Baoquan He Cc: David Gow Cc: Dmitriy Vyukov Cc: Heiko Carstens Cc: Huacai Chen Cc: Marco Elver Cc: Qing Zhang Cc: Sabyrzhan Tasbolatov Cc: Vincenzo Frascino Signed-off-by: Andrew Morton

um: Remove unused ipi_pipe field from cpuinfo_um

2025-09-10T12:23:58+00:00

It's no longer used after the removal of the SMP implementation in TT mode by commit 28fa468f5316 ("um: Remove broken SMP support"). While at it, remove the outdated comment. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Remove unused cpu_data and current_cpu_data macros

2025-09-10T12:23:55+00:00

These two macros have no users. Remove them. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Stop tracking virtual CPUs via mm_cpumask()

2025-09-10T12:23:53+00:00

In UML, each user address space is represented as a separate stub process on the host. Therefore, user address spaces do not require TLB management on UML virtual CPUs, and it's unnecessary to track which virtual CPUs they have executed on. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Centralize stub size calculations

2025-09-10T12:23:52+00:00

Currently, the stub size is calculated in multiple places. Define a macro that performs the calculation so that the code is easier to read and maintain. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Remove outdated comment about STUB_DATA_PAGES

2025-09-10T12:23:49+00:00

STUB_DATA_PAGES is no longer required to be a power of two since commit 91f0a0c5cc5b ("um: Calculate stub data address relative to stub code"). Remove the outdated comment. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg

um: Remove unused offset and child_err fields from stub_data

2025-09-10T12:23:47+00:00

They are no longer used. Remove them. Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg