Date: Thu, 7 Oct 1999 11:27:56 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: freebsd-current@freebsd.org Subject: i386 wierd one...... kernel stack frame pointer corruption(?) Message-ID: <Pine.BSF.4.10.9910071112290.59620-100000@beppo.feral.com>
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This just started happening over the last day... It's blowing up during
probing because the frame pointer is getting nuked... this is a 2xPPro
machine.
The code in question is:
static u_int64_t
isp_get_portname(isp, loopid, nodename)
struct ispsoftc *isp;
int loopid;
int nodename;
{
u_int64_t wwn = 0;
mbreg_t mbs;
mbs.param[0] = MBOX_GET_PORT_NAME;
mbs.param[1] = loopid << 8;
if (nodename)
mbs.param[1] |= 1;
isp_mboxcmd(isp, &mbs);
Which generates:
000012f0 <isp_get_portname>:
12f0: 55 pushl %ebp
12f1: 89 e5 movl %esp,%ebp
12f3: 83 ec 10 subl $0x10,%esp
12f6: 56 pushl %esi
12f7: 53 pushl %ebx
12f8: bb 00 00 00 00 movl $0x0,%ebx
12fd: be 00 00 00 00 movl $0x0,%esi
1302: 66 c7 45 f0 6a movw $0x6a,0xfffffff0(%ebp)
1307: 00
1308: 8b 4d 0c movl 0xc(%ebp),%ecx
130b: 66 c1 e1 08 shlw $0x8,%cx
130f: 66 89 4d f2 movw %cx,0xfffffff2(%ebp)
1313: 83 7d 10 00 cmpl $0x0,0x10(%ebp)
1317: 74 04 je 131d <isp_get_portname+0x2d>
1319: 80 4d f2 01 orb $0x1,0xfffffff2(%ebp)
131d: 8d 45 f0 leal 0xfffffff0(%ebp),%eax
1320: 50 pushl %eax
1321: ff 75 08 pushl 0x8(%ebp)
1324: e8 b7 27 00 00 call 3ae0 <isp_mboxcmd>
1329: 66 81 7d f0 00 cmpw $0x4000,0xfffffff0(%ebp) <-- EBP is 0
132e: 40
There isn't anything in isp_mboxcmd that I can see would wipe the stack
such that I can see in the C code or the generated output. This code
itself hasn't changed in months.
One thing that is possible is that it's a very deep callstack... It's
during probing and it may have called completion on a completing command
while down at the bottom of the stack starting another command. If you run
out of kernel stack, don't you get some other kind of fault?
-matt
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