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commit a1d416bf9faf4f4871cb5a943614a07f80a7d70f upstream. Since commit38e0edb15b("mm/apply_to_range: call pte function with lazy updates") it's been possible for arch_[enter|leave]_lazy_mmu_mode() to be called without holding a page table lock (for the kernel mappings case), and therefore it is possible that preemption may occur while in the lazy mmu mode. The Sparc lazy mmu implementation is not robust to preemption since it stores the lazy mode state in a per-cpu structure and does not attempt to manage that state on task switch. Powerpc had the same issue and fixed it by explicitly disabling preemption in arch_enter_lazy_mmu_mode() and re-enabling in arch_leave_lazy_mmu_mode(). See commitb9ef323ea1("powerpc/64s: Disable preemption in hash lazy mmu mode"). Given Sparc's lazy mmu mode is based on powerpc's, let's fix it in the same way here. Link: https://lkml.kernel.org/r/20250303141542.3371656-4-ryan.roberts@arm.com Fixes:38e0edb15b("mm/apply_to_range: call pte function with lazy updates") Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Andreas Larsson <andreas@gaisler.com> Acked-by: Juergen Gross <jgross@suse.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juegren Gross <jgross@suse.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.