* [PATCH] s390/diag324: Preserve -EBUSY return code
@ 2026-08-11 14:23 Sumanth Korikkar
2026-08-11 14:57 ` Heiko Carstens
0 siblings, 1 reply; 2+ messages in thread
From: Sumanth Korikkar @ 2026-08-11 14:23 UTC (permalink / raw)
To: linux-s390, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Ilya Leoshkevich, Christian Borntraeger
Cc: sumanthk
When diag324 reports -EBUSY, the error code is
overwritten by the result of copy_to_user() and put_user(). As a result,
the ioctl may incorrectly return success instead of -EBUSY.
Preserve the original diag324 return code and only return -EFAULT when
copying data to userspace fails.
Fixes: 90e6f191e1ee ("s390/diag324: Retrieve power readings via diag 0x324")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
---
arch/s390/kernel/diag/diag324.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/s390/kernel/diag/diag324.c b/arch/s390/kernel/diag/diag324.c
index fe325c2a2d0d..3eec0cc8fb9e 100644
--- a/arch/s390/kernel/diag/diag324.c
+++ b/arch/s390/kernel/diag/diag324.c
@@ -182,8 +182,7 @@ long diag324_pibbuf(unsigned long arg)
goto out;
rc = copy_to_user((void __user *)address, data->pib, data->pib->len);
rc |= put_user(data->sequence, &udata->sequence);
- if (rc)
- rc = -EFAULT;
+ rc = rc ? -EFAULT : data->rc;
out:
mutex_unlock(&pibmutex);
return rc;
--
2.54.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] s390/diag324: Preserve -EBUSY return code
2026-08-11 14:23 [PATCH] s390/diag324: Preserve -EBUSY return code Sumanth Korikkar
@ 2026-08-11 14:57 ` Heiko Carstens
0 siblings, 0 replies; 2+ messages in thread
From: Heiko Carstens @ 2026-08-11 14:57 UTC (permalink / raw)
To: Sumanth Korikkar
Cc: linux-s390, Vasily Gorbik, Alexander Gordeev, Ilya Leoshkevich,
Christian Borntraeger
On Tue, Aug 11, 2026 at 04:23:06PM +0200, Sumanth Korikkar wrote:
> When diag324 reports -EBUSY, the error code is
> overwritten by the result of copy_to_user() and put_user(). As a result,
> the ioctl may incorrectly return success instead of -EBUSY.
>
> Preserve the original diag324 return code and only return -EFAULT when
> copying data to userspace fails.
>
> Fixes: 90e6f191e1ee ("s390/diag324: Retrieve power readings via diag 0x324")
> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
> ---
> arch/s390/kernel/diag/diag324.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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