Date: Wed, 27 Sep 1995 10:24:17 -0400 From: Eugene Stark <stark@UG.CS.SUNYSB.EDU> To: FreeBSD-gnats-submit@freebsd.org Subject: kern/744: Page fault in fchmod() with Sep 20 -stable kernel Message-ID: <199509271424.KAA10038@ws24.ug.cs.sunysb.edu> Resent-Message-ID: <199509271430.HAA02100@freefall.freebsd.org>
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>Number: 744
>Category: kern
>Synopsis: Page fault in fchmod() with Sep 20 -stable kernel
>Confidential: no
>Severity: critical
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Sep 27 07:30:01 PDT 1995
>Last-Modified:
>Originator: Eugene Stark
>Organization:
SUNY at Stony Brook CS Dept.
>Release: FreeBSD 2.1-STABLE supped on Sep 20, 1995
>Environment:
486DX4/100, 32MB RAM, IDE, BusLogic SCSI.
FreeBSD 2.1-STABLE supped on Sep 20, 1995.
>Description:
System crashed due to attempt to follow NULL vp->v_mount
pointer in fchmod() in kern/vfs_syscalls.c.
There has been one revision to vnode code in -STABLE since
that date, but I'm not sure if it is relevant to this problem.
I'll retain this core dump for a little while, in case
anybody wants more information.
gdb -k kernel vmcore.7
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under certain conditions; type "show copying" to see the conditions.
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GDB 4.13 (i386-unknown-freebsd),
Copyright 1994 Free Software Foundation, Inc...
IdlePTD 1c3000
current pcb at 1b6140
panic: page fault
#0 boot (howto=256) at ../../i386/i386/machdep.c:873
873 dumppcb.pcb_ptd = rcr3();
(kgdb) bt
#0 boot (howto=256) at ../../i386/i386/machdep.c:873
#1 0xf010f893 in panic (fmt=0xf018c9fc "page fault")
at ../../kern/subr_prf.c:124
#2 0xf018d4be in trap_fatal (frame=0xefbffe80) at ../../i386/i386/trap.c:718
#3 0xf018d030 in trap_pfault (frame=0xefbffe80, usermode=0)
at ../../i386/i386/trap.c:640
#4 0xf018cce7 in trap (frame={tf_es = -266665968, tf_ds = -227672048,
tf_edi = -255635968, tf_esi = 0, tf_ebp = -272629940,
tf_isp = -267232531, tf_ebx = -257021696, tf_edx = -258090496,
tf_ecx = 29, tf_eax = 0, tf_trapno = 12, tf_err = -257032192,
tf_eip = -267232531, tf_cs = -267255800, tf_eflags = 66178,
tf_esp = -272629868, tf_ss = -255635968}) at ../../i386/i386/trap.c:299
#5 0xf0185e7d in calltrap ()
#6 0xf0125aed in fchmod (p=0xf0c34e00, uap=0xefbfff94, retval=0xefbfff8c)
at ../../kern/vfs_syscalls.c:1503
#7 0xf018d703 in syscall (frame={tf_es = 39, tf_ds = 39, tf_edi = 136768,
tf_esi = 0, tf_ebp = -272640484, tf_isp = -272629788, tf_ebx = 147456,
tf_edx = 147524, tf_ecx = 0, tf_eax = 124, tf_trapno = 514,
tf_err = 514, tf_eip = 134525525, tf_cs = 31, tf_eflags = 514,
tf_esp = -272640504, tf_ss = 39}) at ../../i386/i386/trap.c:853
#8 0xf0185ecb in Xsyscall ()
#9 0xde0a in ?? ()
#10 0xcf51 in ?? ()
#11 0x10d3 in ?? ()
(kgdb) frame 6
#6 0xf0125aed in fchmod (p=0xf0c34e00, uap=0xefbfff94, retval=0xefbfff8c)
at ../../kern/vfs_syscalls.c:1503
1503 if (vp->v_mount->mnt_flag & MNT_RDONLY)
(kgdb) print *vp
$1 = {v_flag = 0, v_usecount = 1, v_writecount = 1, v_holdcnt = 0,
v_lastr = 0, v_id = 2194101, v_mount = 0x0, v_op = 0xf09dda00, v_freelist = {
tqe_next = 0x0, tqe_prev = 0xf0ae209c}, v_mntvnodes = {
le_next = 0xf0b37a80, le_prev = 0xf0b1b424}, v_cleanblkhd = {
lh_first = 0x0}, v_dirtyblkhd = {lh_first = 0x0}, v_numoutput = 0,
v_type = VBAD, v_un = {vu_mountedhere = 0x0, vu_socket = 0x0,
vu_specinfo = 0x0, vu_fifoinfo = 0x0}, v_lease = 0x0, v_lastw = 0,
v_cstart = 0, v_lasta = 0, v_clen = 0, v_ralen = 0, v_maxra = 0,
v_vmdata = 0x0, v_tag = VT_NON, v_data = 0x0}
(kgdb) print *p
$2 = {p_forw = 0xf0bf8200, p_back = 0x0, p_next = 0xf0c41a00,
p_prev = 0xf0a4fd08, p_cred = 0xf0bd1f40, p_fd = 0xf0c63700,
p_stats = 0xf4610288, p_limit = 0xf01bc74c, p_vmspace = 0xf0ad4000,
p_sigacts = 0xf461015c, p_flag = 16390, p_stat = 2 '\002',
p_pad1 = "\000\000", p_pid = 15224, p_hash = 0x0, p_pgrpnxt = 0x0,
p_pptr = 0xf09e7e00, p_osptr = 0xf0a83300, p_ysptr = 0x0, p_cptr = 0x0,
p_oppid = 0, p_dupfd = 0, p_estcpu = 71, p_cpticks = 70, p_pctcpu = 34,
p_wchan = 0x0, p_wmesg = 0xf01112b4 "select", p_swtime = 660, p_slptime = 0,
p_realtimer = {it_interval = {tv_sec = 0, tv_usec = 0}, it_value = {
tv_sec = 0, tv_usec = 0}}, p_rtime = {tv_sec = 2, tv_usec = 682432},
p_uticks = 53, p_sticks = 376, p_iticks = 12, p_traceflag = 0,
p_tracep = 0x0, p_siglist = 0, p_textvp = 0xf0af4300, p_lock = 0 '\000',
p_pad2 = "\000\000", p_spare = {0, 0}, p_sigmask = 0,
p_sigignore = 406884353, p_sigcatch = 548870, p_priority = 67 'C',
p_usrpri = 67 'C', p_nice = 0 '\000',
p_comm = "slirp\000d\000\000\000\000\000\000\000\000\000",
p_pgrp = 0xf0bee600, p_sysent = 0xf01ac020, p_rtprio = {type = 1, prio = 0},
p_thread = 6, p_addr = 0xf4610000, p_md = {md_flags = 0,
md_regs = 0xefbfffbc}, p_xstat = 0, p_acflag = 0, p_ru = 0x0}
(kgdb)
>How-To-Repeat:
Unknown.
>Fix:
Unknown.
>Audit-Trail:
>Unformatted:
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