Date: Thu, 31 Aug 2000 06:21:23 -0700 From: Don Lewis <Don.Lewis@tsc.tdk.com> To: Tor.Egge@fast.no, rwatson@FreeBSD.ORG Cc: ohartman@ipamzlx.physik.uni-mainz.de, freebsd-stable@FreeBSD.ORG, cvs-committers@FreeBSD.ORG Subject: Re: 4.1 STABLE broken since today! Message-ID: <200008311321.GAA09415@salsa.gv.tsc.tdk.com> In-Reply-To: <200008310411.GAA63367@midten.fast.no> References: <Pine.NEB.3.96L.1000830222247.18759A-100000@fledge.watson.org> <200008310411.GAA63367@midten.fast.no>
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On Aug 31, 6:11am, Tor.Egge@fast.no wrote:
} Subject: Re: 4.1 STABLE broken since today!
} >
} > As commented on freebsd-current, this seems to have hit the -CURRENT
} > kernel at the same time. Someone should *not* have MFC'd some change
} > immediately. Not clear who yet. I'm suspicious of the sbappend() changes
} > that have been going in recently.
}
}
} 1. The value of diff in chgsbsize was always positive
} (unsigned - unsigned results in an unsigned value).
} This causes bogus values in ui_sbsize.
[ snip ]
} The following patch works for me.
}
} Index: sys/kern/kern_proc.c
} ===================================================================
} RCS file: /home/ncvs/src/sys/kern/kern_proc.c,v
} retrieving revision 1.72
} diff -u -r1.72 kern_proc.c
} --- sys/kern/kern_proc.c 2000/08/30 04:49:07 1.72
} +++ sys/kern/kern_proc.c 2000/08/31 03:56:30
} @@ -210,7 +211,7 @@
} if (uip == NULL)
} uip = uicreate(uid);
} s = splnet();
} - diff = to - *hiwat;
} + diff = (rlim_t) to - (rlim_t) *hiwat;
} /* don't allow them to exceed max, but allow subtraction */
} if (diff > 0 && uip->ui_sbsize + diff > max) {
} (void)uifree(uip);
This depends on rlim_t being a signed type (which is happens to be).
Also, if "to" is the same width as rlim_t, then this code could break
if the difference was greater than the maximum positive value of rlim_t
(not likely in this particular case). Changing the test from
diff > 0
to
to > *hiwat
is much safer.
I prefer the following patch to kern_proc.c, which also pulls uifree()
out of splnet(), and eliminates some duplicate code. I'm not yet running
4-stable, so I can't test this patch other than to see if it compiles
without error.
--- kern_proc.c- Wed Aug 30 05:29:52 2000
+++ kern_proc.c Thu Aug 31 05:57:11 2000
@@ -201,7 +201,8 @@
rlim_t max;
{
struct uidinfo *uip;
- rlim_t diff;
+ rlim_t new;
+ int ok = 0;
int s;
uip = uifind(uid);
@@ -210,18 +211,16 @@
if (uip == NULL)
uip = uicreate(uid);
s = splnet();
- diff = to - *hiwat;
+ new = uip->ui_sbsize + to - *hiwat;
/* don't allow them to exceed max, but allow subtraction */
- if (diff > 0 && uip->ui_sbsize + diff > max) {
- (void)uifree(uip);
- splx(s);
- return (0);
+ if (to <= *hiwat || new <= max) {
+ uip->ui_sbsize = new;
+ *hiwat = to;
+ ok = 1;
}
- uip->ui_sbsize += diff;
- *hiwat = to;
- (void)uifree(uip);
splx(s);
- return (1);
+ (void)uifree(uip);
+ return (ok);
}
/*
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