On 01.09.25 15:09, Simon Schuster via B4 Relay wrote:
From: Simon Schuster <schuster.si...@siemens-energy.com>

With the introduction of clone3 in commit 7f192e3cd316 ("fork: add
clone3") the effective bit width of clone_flags on all architectures was
increased from 32-bit to 64-bit. However, the signature of the copy_*
helper functions (e.g., copy_sighand) used by copy_process was not
adapted.

As such, they truncate the flags on any 32-bit architectures that
supports clone3 (arc, arm, csky, m68k, microblaze, mips32, openrisc,
parisc32, powerpc32, riscv32, x86-32 and xtensa).

For copy_sighand with CLONE_CLEAR_SIGHAND being an actual u64
constant, this triggers an observable bug in kernel selftest
clone3_clear_sighand:

         if (clone_flags & CLONE_CLEAR_SIGHAND)

in function copy_sighand within fork.c will always fail given:

         unsigned long /* == uint32_t */ clone_flags
         #define CLONE_CLEAR_SIGHAND 0x100000000ULL

This commit fixes the bug by always passing clone_flags to copy_sighand
via their declared u64 type, invariant of architecture-dependent integer
sizes.

Fixes: b612e5df4587 ("clone3: add CLONE_CLEAR_SIGHAND")
Cc: sta...@vger.kernel.org # linux-5.5+
Signed-off-by: Simon Schuster <schuster.si...@siemens-energy.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoa...@oracle.com>
---

(stripping To list)

Acked-by: David Hildenbrand <da...@redhat.com>

--
Cheers

David / dhildenb


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