2022-05-18 03:48:51

by Schspa Shi

Subject: [PATCH v2] binder: fix atomic sleep when get extended error

binder_inner_proc_lock(thread->proc) is a spin lock, copy_to_user can't
be called with in this lock.

Copy it as a local variable to fix it.

Reported-by: [email protected]
Fixes: bd32889e841c ("binder: add BINDER_GET_EXTENDED_ERROR ioctl")
Signed-off-by: Schspa Shi <[email protected]>

---

Changelog:
v1 -> v2:
- Remove the retry as Carlos Llamas adviced.
- Use binder_set_extended_error to reset the error info.
---
drivers/android/binder.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index d9253b2a7bd9..1a6b7a8c8346 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -5162,19 +5162,16 @@ static int binder_ioctl_get_freezer_info(
static int binder_ioctl_get_extended_error(struct binder_thread *thread,
void __user *ubuf)
{
- struct binder_extended_error *ee = &thread->ee;
+ struct binder_extended_error ee;

binder_inner_proc_lock(thread->proc);
- if (copy_to_user(ubuf, ee, sizeof(*ee))) {
- binder_inner_proc_unlock(thread->proc);
- return -EFAULT;
- }
-
- ee->id = 0;
- ee->command = BR_OK;
- ee->param = 0;
+ ee = thread->ee;
+ binder_set_extended_error(&thread->ee, 0, BR_OK, 0);
binder_inner_proc_unlock(thread->proc);

+ if (copy_to_user(ubuf, &ee, sizeof(ee)))
+ return -EFAULT;
+
return 0;
}

--
2.24.3 (Apple Git-128)

2022-05-18 04:12:31

by Carlos Llamas

Subject: Re: [PATCH v2] binder: fix atomic sleep when get extended error

On Wed, May 18, 2022 at 09:17:54AM +0800, Schspa Shi wrote:
> binder_inner_proc_lock(thread->proc) is a spin lock, copy_to_user can't
> be called with in this lock.
>
> Copy it as a local variable to fix it.
>
> Reported-by: [email protected]
> Fixes: bd32889e841c ("binder: add BINDER_GET_EXTENDED_ERROR ioctl")
> Signed-off-by: Schspa Shi <[email protected]>
>
> ---
>
> Changelog:
> v1 -> v2:
> - Remove the retry as Carlos Llamas adviced.
> - Use binder_set_extended_error to reset the error info.
> ---

LGTM, thanks.

Reviewed-by: Carlos Llamas <[email protected]>

--
Carlos Llamas