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>
---
kernel/fork.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 5115be549234..82f5d52fecf1 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1599,7 +1599,7 @@ static int copy_files(unsigned long clone_flags, struct
task_struct *tsk,
return 0;
}
-static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
+static int copy_sighand(u64 clone_flags, struct task_struct *tsk)
{
struct sighand_struct *sig;
--
2.39.5
