Date: Wed, 3 May 2000 20:19:19 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: Howard Leadmon <howardl@account.abs.net> Cc: Greg Lehey <grog@lemis.com>, freebsd-stable@FreeBSD.ORG, freebsd-hackers@FreeBSD.ORG Subject: Re: Debugging Kernel/System Crashes, can anyone help?? Message-ID: <200005040319.UAA66688@apollo.backplane.com> References: <200005040255.WAA61544@account.abs.net>
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:#14 0xc0227c57 in trap (frame={tf_fs = 24, tf_es = -675545072,
: tf_ds = -1058602992, tf_edi = -1059013248, tf_esi = 28,
: tf_ebp = -8360071, tf_isp = -8360160, tf_ebx = -1058670080,
: tf_edx = -1059008325, tf_ecx = 0, tf_eax = -1059168256, tf_trapno = 12,
: tf_err = 2, tf_eip = -1072225173, tf_cs = 8, tf_eflags = 66178,
: tf_esp = -1071902645, tf_ss = -1059168256}) at ../../i386/i386/trap.c:423
:#15 0xc017246b in bpfioctl (dev=0xc0c0de60, cmd=12639866,
: addr=0xff400800 <Address 0xff400800 out of bounds>, flags=16777215,
: p=0xacc0de60) at ../../net/bpf.c:683
:#16 0xc01c19 in ?? ()
:cannot read proc at 0
:(kgdb)
:
:
:Is this more help? (shame I don't actually understand it..)
:
:Howard Leadmon - howardl@abs.net - http://www.abs.net
Ahhhh hah! Yes, I think I see what is happening.
The kernel ioctl() system call is using a stack based
char buffer to hold the temporary data, and this buffer is not
aligned.
Please try the following patch.
-Matt
Matthew Dillon
<dillon@backplane.com>
Index: kern/sys_generic.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/sys_generic.c,v
retrieving revision 1.55
diff -u -r1.55 sys_generic.c
--- kern/sys_generic.c 2000/02/20 13:36:26 1.55
+++ kern/sys_generic.c 2000/05/04 03:18:02
@@ -496,7 +496,10 @@
caddr_t data, memp;
int tmp;
#define STK_PARAMS 128
- char stkbuf[STK_PARAMS];
+ union {
+ char stkbuf[STK_PARAMS];
+ long align;
+ } ubuf;
fdp = p->p_fd;
if ((u_int)uap->fd >= fdp->fd_nfiles ||
@@ -523,11 +526,11 @@
if (size > IOCPARM_MAX)
return (ENOTTY);
memp = NULL;
- if (size > sizeof (stkbuf)) {
+ if (size > sizeof (ubuf.stkbuf)) {
memp = (caddr_t)malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
data = memp;
} else
- data = stkbuf;
+ data = ubuf.stkbuf;
if (com&IOC_IN) {
if (size) {
error = copyin(uap->data, data, (u_int)size);
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