On 01.09.25 15:09, Simon Schuster via B4 Relay wrote:
From: Simon Schuster schuster.simon@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 0x100000000ULLThis 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: stable@vger.kernel.org # linux-5.5+ Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com
(stripping To list)
Acked-by: David Hildenbrand david@redhat.com