Hi Andrew,
On 12/04/2014 12:25 AM, Andrew Morton wrote:
On Wed, 03 Dec 2014 15:41:21 +0300 Andrey Ryabinin <a.ryabi...@samsung.com>
wrote:
Use the 'unsigned long' type for 'zero' variable to fix this.
Changing type to 'unsigned long' shouldn't affect any other users
of this variable.
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Fixes: ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
Signed-off-by: Andrey Ryabinin <a.ryabi...@samsung.com>
---
kernel/sysctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 15f2511..45c45c9 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -120,7 +120,7 @@ static int sixty = 60;
static int __maybe_unused neg_one = -1;
-static int zero;
+static unsigned long zero;
static int __maybe_unused one = 1;
static int __maybe_unused two = 2;
static int __maybe_unused four = 4;
Yeah, this is ghastly.
Look at
{
.procname = "numa_balancing",
.data = NULL, /* filled in by handler */
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = sysctl_numa_balancing,
.extra1 = &zero,
.extra2 = &one,
},
Now extra1 points at a long and extra2 points at an int.
sysctl_numa_balancing() calls proc_dointvec_minmax() and I think your
patch just broke big-endian 64-bit machines. "sched_autogroup_enabled"
breaks as well.
What about getting rid of "extra1" and "extra2" as well and replace it
with "min" and "max"?
I've attached an idea
and change proc_dointvec_minmax() and a million other functions to take
`union sysctl_payload *' arguments. But I haven't thought about it much.
Another idea: why do we pass "int *" instead of "int"?
With "int", we could use
.int_min = 0;
.int_max = 1;
--
Manfred
>From 7a210bec3d9dc3382ef0d6809a7742856373bbee Mon Sep 17 00:00:00 2001
From: Manfred Spraul <manf...@colorfullife.com>
Date: Thu, 4 Dec 2014 07:03:39 +0100
Subject: [PATCH] Allow type safe & documented sysctl
Idea from Andrew:
- add a union into struct ctl_table instead of the void *
- further idea: replace "extra1" and "extra2" with min/max
- use it for ipc
Notes:
- not tested
- not coding style reviewed
- open FIXME in ipc_sysctl.c
Signed-off-by: Manfred Spraul <manf...@colorfullife.com>
---
include/linux/sysctl.h | 16 ++++++++++++++--
ipc/ipc_sysctl.c | 34 ++++++++++++++++++----------------
2 files changed, 32 insertions(+), 18 deletions(-)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index b7361f8..acc7581 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -111,8 +111,20 @@ struct ctl_table
struct ctl_table *child; /* Deprecated */
proc_handler *proc_handler; /* Callback for text formatting */
struct ctl_table_poll *poll;
- void *extra1;
- void *extra2;
+ union {
+ void *extra1;
+ int *int_min;
+ long *long_min;
+ unsigned int *uint_min;
+ unsigned long *ulong_min;
+ };
+ union {
+ void *extra2;
+ int *int_max;
+ long *long_max;
+ unsigned int *uint_max;
+ unsigned long *ulong_max;
+ };
};
struct ctl_node {
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index c3f0326..50a6e1c 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -167,6 +167,7 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.shm_ctlmax),
.mode = 0644,
.proc_handler = proc_ipc_doulongvec_minmax,
+ /* FIXME: Why no ulong_min & ulong_max ?? */
},
{
.procname = "shmall",
@@ -174,6 +175,7 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.shm_ctlall),
.mode = 0644,
.proc_handler = proc_ipc_doulongvec_minmax,
+ /* FIXME: Why no ulong_min & ulong_max ?? */
},
{
.procname = "shmmni",
@@ -188,8 +190,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax_orphans,
- .extra1 = &zero,
- .extra2 = &one,
+ .int_min = &zero,
+ .int_max = &one,
},
{
.procname = "msgmax",
@@ -197,8 +199,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.msg_ctlmax),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &int_max,
+ .int_min = &zero,
+ .int_max = &int_max,
},
{
.procname = "msgmni",
@@ -206,8 +208,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.msg_ctlmni),
.mode = 0644,
.proc_handler = proc_ipc_callback_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &int_max,
+ .int_min = &zero,
+ .int_max = &int_max,
},
{
.procname = "msgmnb",
@@ -215,8 +217,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &int_max,
+ .int_min = &zero,
+ .int_max = &int_max,
},
{
.procname = "sem",
@@ -231,8 +233,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_ipcauto_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &one,
+ .int_min = &zero,
+ .int_max = &one,
},
#ifdef CONFIG_CHECKPOINT_RESTORE
{
@@ -241,8 +243,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &int_max,
+ .int_min = &zero,
+ .int_max = &int_max,
},
{
.procname = "msg_next_id",
@@ -250,8 +252,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &int_max,
+ .int_min = &zero,
+ .int_max = &int_max,
},
{
.procname = "shm_next_id",
@@ -259,8 +261,8 @@ static struct ctl_table ipc_kern_table[] = {
.maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &int_max,
+ .int_min = &zero,
+ .int_max = &int_max,
},
#endif
{}
--
1.9.3
