[PATCH] stackleak: let stack_erasing_sysctl take a kernel pointer buffer

From: Tobias Klauser
Date: Tue Aug 25 2020 - 04:58:57 EST


Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of stack_erasing_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:

kernel/stackleak.c:31:50: warning: incorrect type in argument 3 (different address spaces)
kernel/stackleak.c:31:50: expected void *
kernel/stackleak.c:31:50: got void [noderef] __user *buffer

Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Tobias Klauser <tklauser@xxxxxxxxxx>
---
include/linux/stackleak.h | 2 +-
kernel/stackleak.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h
index 3d5c3271a9a8..a59db2f08e76 100644
--- a/include/linux/stackleak.h
+++ b/include/linux/stackleak.h
@@ -25,7 +25,7 @@ static inline void stackleak_task_init(struct task_struct *t)

#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
int stack_erasing_sysctl(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos);
+ void *buffer, size_t *lenp, loff_t *ppos);
#endif

#else /* !CONFIG_GCC_PLUGIN_STACKLEAK */
diff --git a/kernel/stackleak.c b/kernel/stackleak.c
index a8fc9ae1d03d..ce161a8e8d97 100644
--- a/kernel/stackleak.c
+++ b/kernel/stackleak.c
@@ -20,7 +20,7 @@
static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass);

int stack_erasing_sysctl(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
+ void *buffer, size_t *lenp, loff_t *ppos)
{
int ret = 0;
int state = !static_branch_unlikely(&stack_erasing_bypass);
--
2.27.0