forked from Minki/linux
2d602bf283
In 'struct acct', 'struct acct_v3', and 'struct taskstats' we have a 32-bit 'ac_btime' field containing an absolute time value, which will overflow in year 2106. There are two possible ways to deal with it: a) let it overflow and have user space code deal with reconstructing the data based on the current time, or b) truncate the times based on the range of the u32 type. Neither of them solves the actual problem. Pick the second one to best document what the issue is, and have someone fix it in a future version. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
177 lines
4.7 KiB
C
177 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* tsacct.c - System accounting over taskstats interface
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*
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* Copyright (C) Jay Lan, <jlan@sgi.com>
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*/
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#include <linux/kernel.h>
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#include <linux/sched/signal.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/cputime.h>
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#include <linux/tsacct_kern.h>
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#include <linux/acct.h>
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#include <linux/jiffies.h>
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#include <linux/mm.h>
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/*
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* fill in basic accounting fields
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*/
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void bacct_add_tsk(struct user_namespace *user_ns,
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struct pid_namespace *pid_ns,
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struct taskstats *stats, struct task_struct *tsk)
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{
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const struct cred *tcred;
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u64 utime, stime, utimescaled, stimescaled;
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u64 delta;
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time64_t btime;
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BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
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/* calculate task elapsed time in nsec */
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delta = ktime_get_ns() - tsk->start_time;
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/* Convert to micro seconds */
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do_div(delta, NSEC_PER_USEC);
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stats->ac_etime = delta;
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/* Convert to seconds for btime (note y2106 limit) */
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btime = ktime_get_real_seconds() - div_u64(delta, USEC_PER_SEC);
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stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
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if (thread_group_leader(tsk)) {
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stats->ac_exitcode = tsk->exit_code;
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if (tsk->flags & PF_FORKNOEXEC)
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stats->ac_flag |= AFORK;
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}
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if (tsk->flags & PF_SUPERPRIV)
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stats->ac_flag |= ASU;
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if (tsk->flags & PF_DUMPCORE)
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stats->ac_flag |= ACORE;
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if (tsk->flags & PF_SIGNALED)
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stats->ac_flag |= AXSIG;
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stats->ac_nice = task_nice(tsk);
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stats->ac_sched = tsk->policy;
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stats->ac_pid = task_pid_nr_ns(tsk, pid_ns);
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rcu_read_lock();
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tcred = __task_cred(tsk);
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stats->ac_uid = from_kuid_munged(user_ns, tcred->uid);
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stats->ac_gid = from_kgid_munged(user_ns, tcred->gid);
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stats->ac_ppid = pid_alive(tsk) ?
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task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;
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rcu_read_unlock();
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task_cputime(tsk, &utime, &stime);
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stats->ac_utime = div_u64(utime, NSEC_PER_USEC);
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stats->ac_stime = div_u64(stime, NSEC_PER_USEC);
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task_cputime_scaled(tsk, &utimescaled, &stimescaled);
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stats->ac_utimescaled = div_u64(utimescaled, NSEC_PER_USEC);
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stats->ac_stimescaled = div_u64(stimescaled, NSEC_PER_USEC);
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stats->ac_minflt = tsk->min_flt;
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stats->ac_majflt = tsk->maj_flt;
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strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
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}
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#ifdef CONFIG_TASK_XACCT
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#define KB 1024
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#define MB (1024*KB)
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#define KB_MASK (~(KB-1))
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/*
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* fill in extended accounting fields
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*/
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void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
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{
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struct mm_struct *mm;
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/* convert pages-nsec/1024 to Mbyte-usec, see __acct_update_integrals */
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stats->coremem = p->acct_rss_mem1 * PAGE_SIZE;
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do_div(stats->coremem, 1000 * KB);
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stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE;
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do_div(stats->virtmem, 1000 * KB);
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mm = get_task_mm(p);
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if (mm) {
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/* adjust to KB unit */
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stats->hiwater_rss = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB;
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stats->hiwater_vm = get_mm_hiwater_vm(mm) * PAGE_SIZE / KB;
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mmput(mm);
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}
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stats->read_char = p->ioac.rchar & KB_MASK;
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stats->write_char = p->ioac.wchar & KB_MASK;
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stats->read_syscalls = p->ioac.syscr & KB_MASK;
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stats->write_syscalls = p->ioac.syscw & KB_MASK;
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#ifdef CONFIG_TASK_IO_ACCOUNTING
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stats->read_bytes = p->ioac.read_bytes & KB_MASK;
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stats->write_bytes = p->ioac.write_bytes & KB_MASK;
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stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes & KB_MASK;
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#else
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stats->read_bytes = 0;
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stats->write_bytes = 0;
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stats->cancelled_write_bytes = 0;
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#endif
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}
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#undef KB
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#undef MB
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static void __acct_update_integrals(struct task_struct *tsk,
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u64 utime, u64 stime)
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{
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u64 time, delta;
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if (!likely(tsk->mm))
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return;
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time = stime + utime;
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delta = time - tsk->acct_timexpd;
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if (delta < TICK_NSEC)
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return;
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tsk->acct_timexpd = time;
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/*
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* Divide by 1024 to avoid overflow, and to avoid division.
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* The final unit reported to userspace is Mbyte-usecs,
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* the rest of the math is done in xacct_add_tsk.
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*/
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tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm) >> 10;
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tsk->acct_vm_mem1 += delta * tsk->mm->total_vm >> 10;
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}
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/**
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* acct_update_integrals - update mm integral fields in task_struct
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* @tsk: task_struct for accounting
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*/
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void acct_update_integrals(struct task_struct *tsk)
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{
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u64 utime, stime;
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unsigned long flags;
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local_irq_save(flags);
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task_cputime(tsk, &utime, &stime);
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__acct_update_integrals(tsk, utime, stime);
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local_irq_restore(flags);
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}
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/**
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* acct_account_cputime - update mm integral after cputime update
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* @tsk: task_struct for accounting
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*/
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void acct_account_cputime(struct task_struct *tsk)
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{
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__acct_update_integrals(tsk, tsk->utime, tsk->stime);
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}
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/**
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* acct_clear_integrals - clear the mm integral fields in task_struct
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* @tsk: task_struct whose accounting fields are cleared
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*/
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void acct_clear_integrals(struct task_struct *tsk)
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{
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tsk->acct_timexpd = 0;
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tsk->acct_rss_mem1 = 0;
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tsk->acct_vm_mem1 = 0;
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}
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#endif
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