kern/83375: Fatal trap 12 cloning a pty

[Marc Olzheim]

The following reply was made to PR kern/83375; it has been noted by GNATS.

From: Marc Olzheim <marcolz at stack.nl>
To: FreeBSD-gnats-submit at FreeBSD.org, freebsd-bugs at FreeBSD.org
Cc: Marc Olzheim <marcolz at stack.nl>
Subject: Re: kern/83375: Fatal trap 12 cloning a pty
Date: Tue, 19 Jul 2005 11:50:01 +0200

 5.4-RELEASE-p4 broke down to me as well:
 
 Fatal trap 12: page fault while in kernel mode
 cpuid = 0; apic id = 00
 fault virtual address   = 0x1c
 fault code              = supervisor write, page not present
 instruction pointer     = 0x8:0xc0512b03
 stack pointer           = 0x10:0xebaeb9bc
 frame pointer           = 0x10:0xebaeb9c8
 code segment            = base 0x0, limit 0xfffff, type 0x1b
                         = DPL 0, pres 1, def32 1, gran 1
 processor eflags        = interrupt enabled, resume, IOPL = 0
 current process         = 5514 (screen)
 [thread pid 5514 tid 100166 ]
 Stopped at      0xc0512b03 = knote+0x27:        lock cmpxchgl   %ecx,0x1c(%edx)
 db> trace
 Tracing pid 5514 tid 100166 td 0xc5cb3900
 knote(c5e96c80,0,0,c5e96c10,c5e96c00) at 0xc0512b03 = knote+0x27
 ttwakeup(c5e96c00,c5e96c00,c5e96c00,c65d7200,ebaeba14) at 0xc055c465 = ttwakeup+0x65
 ttymodem(c5e96c00,1) at 0xc055b0c8 = ttymodem+0x170
 ptcopen(c65d7200,3,2000,c5cb3900,c0710800) at 0xc055edb3 = ptcopen+0x63
 spec_open(ebaeba80,ebaebb3c,c058cd35,ebaeba80,180) at 0xc04f19ce = spec_open+0x2b6
 spec_vnoperate(ebaeba80) at 0xc04f1713 = spec_vnoperate+0x13
 vn_open_cred(ebaebbe4,ebaebce4,0,c6e64400,a) at 0xc058cd35 = vn_open_cred+0x419
 vn_open(ebaebbe4,ebaebce4,0,a,0) at 0xc058c91a = vn_open+0x1e
 kern_open(c5cb3900,bfbfc6a0,0,3,0) at 0xc05867c7 = kern_open+0xeb
 open(c5cb3900,ebaebd14,3,1,292) at 0xc05866d8 = open+0x18
 syscall(bfbf002f,2f,bfbf002f,ffffffff,28104c2d) at 0xc0699677 = syscall+0x2b3
 Xint0x80_syscall() at 0xc06885ef = Xint0x80_syscall+0x1f
 --- syscall (5, FreeBSD ELF32, open), eip = 0x2816c7bb, esp = 0xbfbfc66c, ebp = 0xbfbfc6c8 ---
 db> show reg
 cs                 0x8
 ds                0x10
 es           0x1000010
 fs          0xebae0018
 ss                0x10
 eax                0x4
 ecx         0xc5cb3900
 edx                  0
 ebx         0xc5e96c00
 esp         0xebaeb9bc
 ebp         0xebaeb9c8
 esi         0xc65d7200
 edi         0xc65ce630
 eip         0xc0512b03  knote+0x27
 efl            0x10246
 dr0                  0
 dr1                  0
 dr2                  0
 dr3                  0
 dr4         0xffff0ff0
 dr5              0x400
 dr6         0xffff0ff0
 dr7              0x400
 0xc0512b03 = knote+0x27:        lock cmpxchgl   %ecx,0x1c(%edx)
 db>