Re: [PATCH] capability: erase checker warnings about struct __user_cap_data_struct
From: "Serge E. Hallyn" <serge@hallyn.com>
Date: 2023-06-06 03:29:07
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On Fri, Jun 02, 2023 at 01:45:27PM +0800, GONG, Ruiqi wrote:
Currently Sparse warns the following when compiling kernel/capability.c: kernel/capability.c:191:35: warning: incorrect type in argument 2 (different address spaces) kernel/capability.c:191:35: expected void const *from kernel/capability.c:191:35: got struct __user_cap_data_struct [noderef] __user * kernel/capability.c:168:14: warning: dereference of noderef expression ...... (multiple noderef warnings on different locations) kernel/capability.c:244:29: warning: incorrect type in argument 1 (different address spaces) kernel/capability.c:244:29: expected void *to kernel/capability.c:244:29: got struct __user_cap_data_struct [noderef] __user ( * )[2] kernel/capability.c:247:42: warning: dereference of noderef expression ...... (multiple noderef warnings on different locations) It seems that defining `struct __user_cap_data_struct` together with `cap_user_data_t` make Sparse believe that the struct is `noderef` as well. Separate their definitions to clarify their respective attributes. Signed-off-by: GONG, Ruiqi <redacted>
Seems ok. There's still so much noise in the make C=2 output even just for kernel/capability.c that I'm not sure it's worth it, but no objection. Acked-by: Serge Hallyn <serge@hallyn.com>
quoted hunk ↗ jump to hunk
--- include/uapi/linux/capability.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h index 3d61a0ae055d..5bb906098697 100644 --- a/include/uapi/linux/capability.h +++ b/include/uapi/linux/capability.h@@ -41,11 +41,12 @@ typedef struct __user_cap_header_struct { int pid; } __user *cap_user_header_t; -typedef struct __user_cap_data_struct { +struct __user_cap_data_struct { __u32 effective; __u32 permitted; __u32 inheritable; -} __user *cap_user_data_t; +}; +typedef struct __user_cap_data_struct __user *cap_user_data_t; #define VFS_CAP_REVISION_MASK 0xFF000000-- 2.25.1