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Properly lock proctree_lock before locking the process while accounting.

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During the import of the MPSAFE TTY layer (r181905), I changed
acct_process() to lock proctree_lock instead of SESS_LOCK, because
s_ttyp is now locked using proctree_lock. One of the things I forgot,
was to lock it before we PROC_LOCK.

Commit this patch, written by kib@. To ensure we hold proctree_lock as
short as possible, obtaining `ac_tty' has now been made the first step
of filling `acct'.

Reported by:	Kevin <kevinxlinuz 163 com>
Solved by:	kib
This commit is contained in:
Ed Schouten 2008-08-21 15:02:17 +00:00
parent 8acee1c0ca
commit 40572ab385
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=181963
1 changed files with 15 additions and 14 deletions
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29
sys/kern/kern_acct.c
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@ -366,16 +366,25 @@ acct_process(struct thread *td)
* Get process accounting information.
*/
sx_slock(&proctree_lock);
PROC_LOCK(p);
/* (1) The name of the command that ran */
/* (1) The terminal from which the process was started */
if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp);
else
acct.ac_tty = NODEV;
sx_sunlock(&proctree_lock);
/* (2) The name of the command that ran */
bcopy(p->p_comm, acct.ac_comm, sizeof acct.ac_comm);
/* (2) The amount of user and system time that was used */
/* (3) The amount of user and system time that was used */
rufetchcalc(p, &ru, &ut, &st);
acct.ac_utime = encode_timeval(ut);
acct.ac_stime = encode_timeval(st);
/* (3) The elapsed time the command ran (and its starting time) */
/* (4) The elapsed time the command ran (and its starting time) */
tmp = boottime;
timevaladd(&tmp, &p->p_stats->p_start);
acct.ac_btime = tmp.tv_sec;
@ -383,7 +392,7 @@ acct_process(struct thread *td)
timevalsub(&tmp, &p->p_stats->p_start);
acct.ac_etime = encode_timeval(tmp);
/* (4) The average amount of memory used */
/* (5) The average amount of memory used */
tmp = ut;
timevaladd(&tmp, &st);
/* Convert tmp (i.e. u + s) into hz units to match ru_i*. */
@ -394,21 +403,13 @@ acct_process(struct thread *td)
else
acct.ac_mem = 0;
/* (5) The number of disk I/O operations done */
/* (6) The number of disk I/O operations done */
acct.ac_io = encode_long(ru.ru_inblock + ru.ru_oublock);
/* (6) The UID and GID of the process */
/* (7) The UID and GID of the process */
acct.ac_uid = p->p_ucred->cr_ruid;
acct.ac_gid = p->p_ucred->cr_rgid;
/* (7) The terminal from which the process was started */
sx_slock(&proctree_lock);
if ((p->p_flag & P_CONTROLT) && p->p_pgrp->pg_session->s_ttyp)
acct.ac_tty = tty_udev(p->p_pgrp->pg_session->s_ttyp);
else
acct.ac_tty = NODEV;
sx_sunlock(&proctree_lock);
/* (8) The boolean flags that tell how the process terminated, etc. */
acct.ac_flagx = p->p_acflag;
PROC_UNLOCK(p);