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y2038: rusage: use __kernel_old_timeval 

There are two 'struct timeval' fields in 'struct rusage'.

Unfortunately the definition of timeval is now ambiguous when used in
user space with a libc that has a 64-bit time_t, and this also changes
the 'rusage' definition in user space in a way that is incompatible with
the system call interface.

While there is no good solution to avoid all ambiguity here, change
the definition in the kernel headers to be compatible with the kernel
ABI, using __kernel_old_timeval as an unambiguous base type.

In previous discussions, there was also a plan to add a replacement
for rusage based on 64-bit timestamps and nanosecond resolution,
i.e. 'struct __kernel_timespec'. I have patches for that as well,
if anyone thinks we should do that.

Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2019-10-25 22:46:48 +02:00
parent 2a785996cc
commit bdd565f817
3 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/alpha/kernel/osf_sys.c
View File

@ -963,7 +963,7 @@ put_tv32(struct timeval32 __user *o, struct timespec64 *i)
} }
static inline long static inline long
put_tv_to_tv32(struct timeval32 __user *o, struct timeval *i) put_tv_to_tv32(struct timeval32 __user *o, struct __kernel_old_timeval *i)
{ {
return copy_to_user(o, &(struct timeval32){ return copy_to_user(o, &(struct timeval32){
.tv_sec = i->tv_sec, .tv_sec = i->tv_sec,

4
include/uapi/linux/resource.h
View File

@ -22,8 +22,8 @@
#define RUSAGE_THREAD 1 /* only the calling thread */ #define RUSAGE_THREAD 1 /* only the calling thread */
struct rusage { struct rusage {
struct timeval ru_utime; /* user time used */ struct __kernel_old_timeval ru_utime; /* user time used */
struct timeval ru_stime; /* system time used */ struct __kernel_old_timeval ru_stime; /* system time used */
__kernel_long_t ru_maxrss; /* maximum resident set size */ __kernel_long_t ru_maxrss; /* maximum resident set size */
__kernel_long_t ru_ixrss; /* integral shared memory size */ __kernel_long_t ru_ixrss; /* integral shared memory size */
__kernel_long_t ru_idrss; /* integral unshared data size */ __kernel_long_t ru_idrss; /* integral unshared data size */

4
kernel/sys.c
View File

@ -1763,8 +1763,8 @@ void getrusage(struct task_struct *p, int who, struct rusage *r)
unlock_task_sighand(p, &flags); unlock_task_sighand(p, &flags);
out: out:
r->ru_utime = ns_to_timeval(utime); r->ru_utime = ns_to_kernel_old_timeval(utime);
r->ru_stime = ns_to_timeval(stime); r->ru_stime = ns_to_kernel_old_timeval(stime);
if (who != RUSAGE_CHILDREN) { if (who != RUSAGE_CHILDREN) {
struct mm_struct *mm = get_task_mm(p); struct mm_struct *mm = get_task_mm(p);