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

Merge tag 'x86_alternatives_for_v7.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-08-19T01:11:25+00:00

Pull x86 alternatives update from Borislav Petkov:

 - Remove the smp_locks alternatives machinery which was used to patch
   out lock prefixes when running a SMP kernel on a uniprocessor machine

* tag 'x86_alternatives_for_v7.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/alternative: Drop smp_locks glue

x86/alternative: Drop smp_locks glue

2026-07-13T16:23:36+00:00

This was there to be able to patch out locking instructions when running
a SMP kernel build on a UP CPU. The times are long gone when single-CPU
x86 machines were relevant so drop that machinery and simplify the code
considerably.

LOCK_PREFIX needs to stay for when one wants to do a UP build for
whatever reason. That'll go away when CONFIG_SMP becomes unconditional.

Kill a bunch of leftover, unused prototypes while at it.

Signed-off-by: Borislav Petkov (AMD) 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Mike Rapoport (Microsoft) 
Link: https://lore.kernel.org/r/20260328081634.797552-1-rppt@kernel.org

ptrace, treewide: Rename ptrace_report_syscall_entry() to ptrace_report_syscall_permit_entry()

2026-07-12T10:38:02+00:00

The return value of that function is boolean and tells the caller whether
to permit the syscall processing or not.

Rename the function so the purpose is clear and make the return type bool.

Signed-off-by: Thomas Gleixner 
Tested-by: Mukesh Kumar Chaurasiya (IBM) 
Reviewed-by: Jinjie Ruan 
Reviewed-by: Radu Rendec 
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) 
Acked-by: Oleg Nesterov 
Acked-by: Magnus Lindholm 
Link: https://patch.msgid.link/20260707190254.280015701@kernel.org

seccomp, treewide: Rename and convert __secure_computing() to return boolean

2026-07-12T10:38:02+00:00

The return value of __secure_computing() currently uses 0 to indicate
that a system call should be allowed, and -1 to indicate that it should
be blocked/killed. This 0/-1 pattern is non-intuitive for a security
check function and makes the control flow at the call sites less readable.

Furthermore, any potential future changes to these return values would
require a high-risk, error-prone audit of all its users across different
architectures.

Sanitize this logic by converting the return type of __secure_computing()
to a proper boolean, where 'true' explicitly means 'allow' and 'false'
means 'fail/deny'.

Update all the two dozen or so call sites across the tree to align with
this new boolean semantic. No functional changes are intended, as the
callers still return -1 to the lower-level assembly entry code upon
seccomp denial.

Rename the function to __seccomp_permit_syscall() so that the purpose is
entirely clear.

[ tglx: Rename the function ]

Suggested-by: Thomas Gleixner 
Suggested-by: Mark Rutland 
Signed-off-by: Jinjie Ruan 
Signed-off-by: Thomas Gleixner 
Tested-by: Mukesh Kumar Chaurasiya (IBM) 
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) 
Acked-by: Oleg Nesterov 
Link: https://patch.msgid.link/20260707190254.230735780@kernel.org

genirq/proc: Increase default interrupt number precision to four

2026-05-26T14:21:14+00:00

Quite some architectures have four character wide acronyms for architecture
specific interrupts like IPI, NMI, etc.

The default precision of printing the Linux device interrupt numbers is
three, which causes quite some code to play games with adding or omitting
space after the acronym and the colon in order to keep the per CPU numbers
properly aligned.

Increase the default number precision to four in the core code and get rid
of the space games all over the place. At the same time align all
architecture specific descriptor texts left so that they show up in the
same column as the interrupt chip names, which makes the output more
uniform accross architectures. Fix up the GDB script to this new scheme as
well.

Signed-off-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260517194931.839482411@kernel.org

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

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

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: 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

um: Fix potential race condition in TLB sync

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

During the TLB sync, we need to traverse and modify the page table,
so we should hold the page table lock. Since full SMP support for
threads within the same process is still missing, let's disable the
split page table lock for simplicity.

Fixes: 1e4ee5135d81 ("um: Add initial SMP support")
Signed-off-by: Tiwei Bie 
Link: https://patch.msgid.link/20260302235224.1915380-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg