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Lock proctree in around fill_kinfo_proc().

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Proctree lock is needed for correct calculation and collection of the
job-control related data in kinfo_proc.  There was even an XXX comment
about it.

Satisfy locking and lock ordering requirements by taking proctree lock
around pass over each bucket in proc_iterate(), and in sysctl_kern_proc()
and note_procstat_proc() for individual process reporting.

Reviewed by:	jilles
Tested by:	pho
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D27871
This commit is contained in:
Konstantin Belousov 2021-01-01 00:29:40 +02:00
parent a008bdeda3
commit 4daea93813
2 changed files with 7 additions and 0 deletions
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2
sys/kern/imgact_elf.c
View file

@ -2386,8 +2386,10 @@ __elfN(note_procstat_proc)(void *arg, struct sbuf *sb, size_t *sizep)
KASSERT(*sizep == size, ("invalid size"));
structsize = sizeof(elf_kinfo_proc_t);
sbuf_bcat(sb, &structsize, sizeof(structsize));
sx_slock(&proctree_lock);
PROC_LOCK(p);
kern_proc_out(p, sb, ELF_KERN_PROC_MASK);
sx_sunlock(&proctree_lock);
}
*sizep = size;
}

5
sys/kern/kern_proc.c
View file

@ -1653,6 +1653,7 @@ proc_iterate(int (*cb)(struct proc *, void *), void *cbarg)
int error, i, j;
for (i = 0; i < pidhashlock + 1; i++) {
sx_slock(&proctree_lock);
sx_slock(&pidhashtbl_lock[i]);
for (j = i; j <= pidhash; j += pidhashlock + 1) {
LIST_FOREACH(p, &pidhashtbl[j], p_hash) {
@ -1662,11 +1663,13 @@ proc_iterate(int (*cb)(struct proc *, void *), void *cbarg)
PROC_LOCK_ASSERT(p, MA_NOTOWNED);
if (error != 0) {
sx_sunlock(&pidhashtbl_lock[i]);
sx_sunlock(&proctree_lock);
return (error);
}
}
}
sx_sunlock(&pidhashtbl_lock[i]);
sx_sunlock(&proctree_lock);
}
return (0);
}
@ -1792,9 +1795,11 @@ sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
error = sysctl_wire_old_buffer(req, 0);
if (error)
return (error);
sx_slock(&proctree_lock);
error = pget((pid_t)name[0], PGET_CANSEE, &p);
if (error == 0)
error = sysctl_out_proc(p, req, flags);
sx_sunlock(&proctree_lock);
return (error);
}