Commit 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
made use of enum pid_type in prctl's arg4; however, this type
and the associated enumeration definitions are not exposed to userspace.
Try to fix that by providing enum __kernel_pidtype and tying in-kernel
enum pid_type definitions to it. Note that enum pid_type cannot be exposed
as is, since "enum pid_type" is already exists in various projects [1]
(notably gcc and strace), and "enum __pid_type" is defined by glibc and uclibc
for fcntl(F_SETOWN_EX) owner ID type; there is also __kernel_pid_t,
that looks too similar to __kernel_pid_type.
[1] https://codesearch.debian.net/search?q=enum+pid_type
Complements: 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
Signed-off-by: Eugene Syromiatnikov <[email protected]>
---
v3:
- Fixed header guard macro: s/_UAPI_LINUX_PID_H/_UAPI_LINUX_PIDTYPE_H/,
as noted by Dmitry Levin.
v2: https://lore.kernel.org/lkml/[email protected]/
- Header file is renamed from pid.h to pidtype.h to avoid collisions
with include/linux/pid.h when included from uapi headers;
- The enum type has renamed from __kernel_pid_type to __kernel_pidtype
to avoid possible confusion with __kernel_pid_t.
v1: https://lore.kernel.org/lkml/[email protected]/
---
.../admin-guide/hw-vuln/core-scheduling.rst | 7 ++++---
include/linux/pid.h | 12 +++++++-----
include/uapi/linux/pidtype.h | 20 ++++++++++++++++++++
include/uapi/linux/prctl.h | 1 +
4 files changed, 32 insertions(+), 8 deletions(-)
create mode 100644 include/uapi/linux/pidtype.h
diff --git a/Documentation/admin-guide/hw-vuln/core-scheduling.rst b/Documentation/admin-guide/hw-vuln/core-scheduling.rst
index 7b410ae..0989c48 100644
--- a/Documentation/admin-guide/hw-vuln/core-scheduling.rst
+++ b/Documentation/admin-guide/hw-vuln/core-scheduling.rst
@@ -61,9 +61,10 @@ arg3:
``pid`` of the task for which the operation applies.
arg4:
- ``pid_type`` for which the operation applies. It is of type ``enum pid_type``.
- For example, if arg4 is ``PIDTYPE_TGID``, then the operation of this command
- will be performed for all tasks in the task group of ``pid``.
+ ``pid_type`` for which the operation applies. It is of type
+ ``enum __kernel_pidtype``. For example, if arg4 is ``__PIDTYPE_TGID``,
+ then the operation of this command will be performed for all tasks
+ in the task group of ``pid``.
arg5:
userspace pointer to an unsigned long for storing the cookie returned by
diff --git a/include/linux/pid.h b/include/linux/pid.h
index fa10acb..57cce71 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -5,14 +5,16 @@
#include <linux/rculist.h>
#include <linux/wait.h>
#include <linux/refcount.h>
+#include <uapi/linux/pidtype.h>
enum pid_type
{
- PIDTYPE_PID,
- PIDTYPE_TGID,
- PIDTYPE_PGID,
- PIDTYPE_SID,
- PIDTYPE_MAX,
+ PIDTYPE_PID = __PIDTYPE_PID,
+ PIDTYPE_TGID = __PIDTYPE_TGID,
+ PIDTYPE_PGID = __PIDTYPE_PGID,
+ PIDTYPE_SID = __PIDTYPE_SID,
+
+ PIDTYPE_MAX = __PIDTYPE_MAX
};
/*
diff --git a/include/uapi/linux/pidtype.h b/include/uapi/linux/pidtype.h
new file mode 100644
index 0000000..759aa29
--- /dev/null
+++ b/include/uapi/linux/pidtype.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_PIDTYPE_H
+#define _UAPI_LINUX_PIDTYPE_H
+
+/*
+ * Type of a process-related ID. So far, it is used only
+ * for prctl(PR_SCHED_CORE); not to be confused with type field
+ * of f_owner_ex structure argument of fcntl(F_SETOWN_EX).
+ */
+enum __kernel_pidtype
+{
+ __PIDTYPE_PID,
+ __PIDTYPE_TGID,
+ __PIDTYPE_PGID,
+ __PIDTYPE_SID,
+
+ __PIDTYPE_MAX /* Non-UAPI */
+};
+
+#endif /* _UAPI_LINUX_PIDTYPE_H */
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 967d9c5..0af570b 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -3,6 +3,7 @@
#define _LINUX_PRCTL_H
#include <linux/types.h>
+#include <linux/pidtype.h> /* enum __kernel_pidtype */
/* Values to pass as first argument to prctl() */
--
2.1.4
On Sat, Aug 07, 2021 at 02:09:05PM +0200, Eugene Syromiatnikov wrote:
> Commit 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
> made use of enum pid_type in prctl's arg4; however, this type
> and the associated enumeration definitions are not exposed to userspace.
> Try to fix that by providing enum __kernel_pidtype and tying in-kernel
> enum pid_type definitions to it. Note that enum pid_type cannot be exposed
> as is, since "enum pid_type" is already exists in various projects [1]
Grammar: "enum pid_type" already exists.
> (notably gcc and strace), and "enum __pid_type" is defined by glibc and uclibc
> for fcntl(F_SETOWN_EX) owner ID type; there is also __kernel_pid_t,
> that looks too similar to __kernel_pid_type.
>
> [1] https://codesearch.debian.net/search?q=enum+pid_type
>
> Complements: 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
> Signed-off-by: Eugene Syromiatnikov <[email protected]>
Reviewed-by: Dmitry V. Levin <[email protected]>
--
ldv