'struct rusage' contains the run times of a process in 'timeval' format and is accessed through the wait4() and getrusage() system calls. This is not a problem for y2038 safety by itself, but causes an issue when the C library starts using 64-bit time_t on 32-bit architectures because the structure layout becomes incompatible.
There are three possible ways of dealing with this: a) deprecate the wait4() and getrusage() system calls, and create a set of kernel interfaces based around a newly defined structure that could solve multiple problems at once, e.g. provide more fine-grained timestamps. The C library could then implement the posix interfaces on top of the new system calls. b) Extend the approach taken by the x32 ABI, and use the 64-bit native structure layout for rusage on all architectures with new system calls that is otherwise compatible. A possible problem here is that we end up with incompatible definitions of rusage between /usr/include/linux/resource.h and /usr/include/bits/resource.h c) Change the definition of struct rusage to be independent of time_t. This is the easiest change, as it does not involve new system call entry points, but it has the risk of introducing compile-time incompatibilities with user space sources that rely on the type of ru_utime and ru_stime. I'm picking approch c) for its simplicity, but I'd like to hear from others whether they would prefer a different approach. Signed-off-by: Arnd Bergmann <[email protected]> --- arch/alpha/kernel/osf_sys.c | 2 +- include/uapi/linux/resource.h | 4 ++-- kernel/sys.c | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c index fa1a392ca9a2..445ded2ea471 100644 --- a/arch/alpha/kernel/osf_sys.c +++ b/arch/alpha/kernel/osf_sys.c @@ -970,7 +970,7 @@ put_tv32(struct timeval32 __user *o, struct timespec64 *i) } 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){ .tv_sec = i->tv_sec, diff --git a/include/uapi/linux/resource.h b/include/uapi/linux/resource.h index cc00fd079631..74ef57b38f9f 100644 --- a/include/uapi/linux/resource.h +++ b/include/uapi/linux/resource.h @@ -22,8 +22,8 @@ #define RUSAGE_THREAD 1 /* only the calling thread */ struct rusage { - struct timeval ru_utime; /* user time used */ - struct timeval ru_stime; /* system time used */ + struct __kernel_old_timeval ru_utime; /* user time used */ + struct __kernel_old_timeval ru_stime; /* system time used */ __kernel_long_t ru_maxrss; /* maximum resident set size */ __kernel_long_t ru_ixrss; /* integral shared memory size */ __kernel_long_t ru_idrss; /* integral unshared data size */ diff --git a/kernel/sys.c b/kernel/sys.c index 83ffd7dccf23..c459e294aa9e 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1717,8 +1717,8 @@ void getrusage(struct task_struct *p, int who, struct rusage *r) unlock_task_sighand(p, &flags); out: - r->ru_utime = ns_to_timeval(utime); - r->ru_stime = ns_to_timeval(stime); + r->ru_utime = ns_to_kernel_old_timeval(utime); + r->ru_stime = ns_to_kernel_old_timeval(stime); if (who != RUSAGE_CHILDREN) { struct mm_struct *mm = get_task_mm(p); -- 2.9.0
