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1b5a42d9c8
In the function bacct_add_task the code reading task->exit_code was introduced in commitf3cef7a994("[PATCH] csa: basic accounting over taskstats"), and it is not entirely clear what the taskstats interface is trying to return as only returning the exit_code of the first task in a process doesn't make a lot of sense. As best as I can figure the intent is to return task->exit_code after a task exits. The field is returned with per task fields, so the exit_code of the entire process is not wanted. Only the value of the first task is returned so this is not a useful way to get the per task ptrace stop code. The ordinary case of returning this value is returning after a task exits, which also precludes use for getting a ptrace value. It is common to for the first task of a process to also be the last task of a process so this field may have done something reasonable by accident in testing. Make ac_exitcode a reliable per task value by always returning it for every exited task. Setting ac_exitcode in a sensible mannter makes it possible to continue to provide this value going forward. Cc: Balbir Singh <bsingharora@gmail.com> Fixes:f3cef7a994("[PATCH] csa: basic accounting over taskstats") Link: https://lkml.kernel.org/r/20220103213312.9144-5-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
176 lines
4.8 KiB
C
176 lines
4.8 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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stats->ac_btime64 = btime;
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if (tsk->flags & PF_EXITING)
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stats->ac_exitcode = tsk->exit_code;
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if (thread_group_leader(tsk) && (tsk->flags & PF_FORKNOEXEC))
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stats->ac_flag |= AFORK;
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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 * READ_ONCE(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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