Date: Thu, 05 Apr 2001 01:39:35 -0500 From: Richard Todd <rmtodd@ichotolot.servalan.com> To: current@freebsd.org Subject: Panic I got: mutex sx backing lock recursed at ../../kern/kern_condvar.c:198 Message-ID: <m14l3Qd-004MUNC@servalan.servalan.com>
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I'm running -CURRENT on a dual PII/400 box with 128M of RAM. The kernel
I'm running was built from sources current as of last night (i.e. around
9PM CDT Apr 3). Just now, while listening to streaming audio with xmms,
the machine crashed. It's done that a couple times before, with recent-ish
kernels while doing streaming audio with xmms, but the other times didn't give
core dumps with usable backtraces. *This* time I got a decent backtrace.
If I'm reading this backtrace right, the thread handling the sound
hardware called selwakeup() (frame #19). This called pfind() (frame
#18), which tries to lock allproc. Somewhere in doing this,
witness_sleep() (frame #15) decides it wants to printf() a message. printf()
calls down into the tty code, which goes into ptsstart() (frame #9) and the
pty code (I'm not entirely sure why). This code then tries to do a selwakeup()
of its own (frame #7) which calls pfind() which tries (again) to lock allproc,
leading to the "mutex recursed" panic.
GDB output and (if it matters) kernel config file below.
Script started on Thu Apr 5 01:12:28 2001
ichotolot# cd /usr/src/sys/compile/ICHOTOLOTSMP
ichotolot# gdb -k kernel.debug /var/crash/vmcore.7
GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-unknown-freebsd"...
IdlePTD 6356992
initial pcb at 513860
panicstr: mutex sx backing lock recursed at ../../kern/kern_condvar.c:198
panic messages:
---
panic: mutex sx backing lock recursed at ../../kern/kern_condvar.c:198
cpuid = 0; lapic.id = 00000000
boot() called on cpu#0
syncing disks... 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16
1: dev:da0s2e, flags:21021024, blkno:11469104, lblkno:11469104
2: dev:da0s2e, flags:21021024, blkno:11468864, lblkno:11468864
3: dev:da0s2e, flags:21000024, blkno:2048, lblkno:2048
4: dev:da0s2e, flags:21021024, blkno:2752848, lblkno:2752848
5: dev:da0s2e, flags:21021024, blkno:2752736, lblkno:2752736
6: dev:da0s2e, flags:21021024, blkno:11468976, lblkno:11468976
7: dev:da0s2a, flags:21021024, blkno:131152, lblkno:131152
8: dev:da0s2e, flags:21021024, blkno:2294176, lblkno:2294176
9: dev:da0s2e, flags:21021024, blkno:2425120, lblkno:2425120
10: dev:da0s2a, flags:21021024, blkno:131184, lblkno:131184
11: dev:da0s2e, flags:21000024, blkno:16, lblkno:16
12: dev:da0s2e, flags:21021024, blkno:2294160, lblkno:2294160
13: dev:da0s2e, flags:21021024, blkno:14221440, lblkno:14221440
14: dev:da0s2e, flags:21021024, blkno:2294192, lblkno:2294192
15: dev:da0s2e, flags:01011024, blkno:11474186, lblkno:0
16: dev:da0s2e, flags:01000024, blkno:11468848, lblkno:11468848
giving up on 16 buffers
Uptime: 23h3m37s
dumping to dev da0s2b, offset 270336
dump 128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
---
#0 dumpsys () at ../../kern/kern_shutdown.c:478
478 if (dumping++) {
(kgdb) bt
#0 dumpsys () at ../../kern/kern_shutdown.c:478
#1 0xc0251547 in boot (howto=256) at ../../kern/kern_shutdown.c:321
#2 0xc0251a09 in panic (fmt=0xc0464a44 "mutex %s recursed at %s:%d")
at ../../kern/kern_shutdown.c:592
#3 0xc024aec3 in _mtx_assert (m=0xc054765c, what=9,
file=0xc0462932 "../../kern/kern_condvar.c", line=198)
at ../../kern/kern_mutex.c:602
#4 0xc02369a2 in cv_wait (cvp=0xc0547698, mp=0xc054765c)
at ../../kern/kern_condvar.c:198
#5 0xc0258caa in _sx_slock (sx=0xc0547640,
file=0xc0464e23 "../../kern/kern_proc.c", line=143)
at ../../kern/kern_sx.c:117
#6 0xc024bf48 in pfind (pid=606) at ../../kern/kern_proc.c:143
#7 0xc026ffe1 in selwakeup (sip=0xc10eea04) at ../../kern/sys_generic.c:1061
#8 0xc027accf in ptcwakeup (tp=0xc10eea20, flag=1) at ../../kern/tty_pty.c:318
#9 0xc027acaa in ptsstart (tp=0xc10eea20) at ../../kern/tty_pty.c:307
#10 0xc0278170 in ttstart (tp=0xc10eea20) at ../../kern/tty.c:1417
#11 0xc027978d in tputchar (c=46, tp=0xc10eea20) at ../../kern/tty.c:2484
#12 0xc0268813 in putchar (c=46, arg=0xc7f12e10) at ../../kern/subr_prf.c:304
#13 0xc0268fb8 in kvprintf (
fmt=0xc0468642 ":%d: %s with \"%s\" locked from %s:%d\n",
func=0xc02687c4 <putchar>, arg=0xc7f12e10, radix=10, ap=0xc7f12e2c "Ç")
at ../../kern/subr_prf.c:637
#14 0xc0268740 in printf (
fmt=0xc0468640 "%s:%d: %s with \"%s\" locked from %s:%d\n")
at ../../kern/subr_prf.c:260
#15 0xc026cff9 in witness_sleep (check_only=0, lock=0xc054765c,
file=0xc0462932 "../../kern/kern_condvar.c", line=199)
at ../../kern/subr_witness.c:725
#16 0xc02369b7 in cv_wait (cvp=0xc0547698, mp=0xc054765c)
at ../../kern/kern_condvar.c:199
#17 0xc0258caa in _sx_slock (sx=0xc0547640,
file=0xc0464e23 "../../kern/kern_proc.c", line=143)
at ../../kern/kern_sx.c:117
#18 0xc024bf48 in pfind (pid=70414) at ../../kern/kern_proc.c:143
#19 0xc026ffe1 in selwakeup (sip=0xc0f59f54) at ../../kern/sys_generic.c:1061
#20 0xc01f5cea in chn_wakeup (c=0xc0f4d580) at ../../dev/sound/pcm/channel.c:97
#21 0xc01f5e4f in chn_wrfeed (c=0xc0f4d580)
at ../../dev/sound/pcm/channel.c:188
#22 0xc01f5e75 in chn_wrintr (c=0xc0f4d580)
at ../../dev/sound/pcm/channel.c:206
#23 0xc01f63dd in chn_intr (c=0xc0f4d580) at ../../dev/sound/pcm/channel.c:407
#24 0xc01df38e in sb_intr (arg=0xc0f4d700) at ../../dev/sound/isa/sb16.c:498
#25 0xc01e12b1 in sbc_intr (p=0xc0f4d9d8) at ../../dev/sound/isa/sbc.c:491
#26 0xc0243823 in ithread_loop (arg=0xc0f4d900) at ../../kern/kern_intr.c:517
#27 0xc0242018 in fork_exit (callout=0xc02433d0 <ithread_loop>,
arg=0xc0f4d900, frame=0xc7f12fa8) at ../../kern/kern_fork.c:731
(kgdb) fr 14
#14 0xc0268740 in printf (
fmt=0xc0468640 "%s:%d: %s with \"%s\" locked from %s:%d\n")
at ../../kern/subr_prf.c:260
260 retval = kvprintf(fmt, putchar, &pca, 10, ap);
(kgdb) l
255 consintr = 0;
256 va_start(ap, fmt);
257 pca.tty = NULL;
258 pca.flags = TOCONS | TOLOG;
259 pca.pri = -1;
260 retval = kvprintf(fmt, putchar, &pca, 10, ap);
261 va_end(ap);
262 if (!panicstr)
263 msgbuftrigger = 1;
264 consintr = savintr; /* reenable interrupts */
(kgdb) fr 15
#15 0xc026cff9 in witness_sleep (check_only=0, lock=0xc054765c,
file=0xc0462932 "../../kern/kern_condvar.c", line=199)
at ../../kern/subr_witness.c:725
725 printf("%s:%d: %s with \"%s\" locked from %s:%d\n",
(kgdb) l
720 lock1 = lle->ll_children[i];
721 if (lock1 == lock || lock1 == &Giant.mtx_object ||
722 (lock1->lo_flags & LO_SLEEPABLE))
723 continue;
724 n++;
725 printf("%s:%d: %s with \"%s\" locked from %s:%d\n",
726 file, line, check_only ? "could sleep" : "sleeping",
727 lock1->lo_name, lock1->lo_file, lock1->lo_line);
728 }
729 if (lock_list == &p->p_sleeplocks) {
(kgdb) p file
$1 = 0xc0462932 "../../kern/kern_condvar.c"
(kgdb) p line
$2 = 199
(kgdb) p check_only
$3 = 0
(kgdb) p lock1
$4 = (struct lock_object *) 0x0
[Is this supposed to be null? -- rmt]
(kgdb) fr 16
#16 0xc02369b7 in cv_wait (cvp=0xc0547698, mp=0xc054765c)
at ../../kern/kern_condvar.c:199
199 WITNESS_SLEEP(0, &mp->mtx_object);
(kgdb) fr 17
#17 0xc0258caa in _sx_slock (sx=0xc0547640,
file=0xc0464e23 "../../kern/kern_proc.c", line=143)
at ../../kern/kern_sx.c:117
117 cv_wait(&sx->sx_shrd_cv, &sx->sx_lock);
(kgdb) fr 18
#18 0xc024bf48 in pfind (pid=70414) at ../../kern/kern_proc.c:143
143 sx_slock(&allproc_lock);
(kgdb) fr 19
#19 0xc026ffe1 in selwakeup (sip=0xc0f59f54) at ../../kern/sys_generic.c:1061
1061 p = pfind(sip->si_pid);
(kgdb) q
ichotolot# cat /usr/src/sys/i386/conf/ICHOTOLOTSMP
#
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
#
# http://www.FreeBSD.org/handbook/kernelconfig-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the NOTES configuration file. If you are
# in doubt as to the purpose or necessity of a line, check first in NOTES.
#
# $FreeBSD: src/sys/i386/conf/GENERIC,v 1.306 2001/03/16 11:52:25 sos Exp $
machine i386
cpu I686_CPU
ident GENERIC
maxusers 32
#To statically compile in device wiring instead of /boot/device.hints
#hints "GENERIC.hints" #Default places to look for devices.
makeoptions DEBUG=-g #Build kernel with gdb(1) debug symbols
options MATH_EMULATE #Support for x87 emulation
options INET #InterNETworking
options INET6 #IPv6 communications protocols
options FFS #Berkeley Fast Filesystem
options SOFTUPDATES #Enable FFS soft updates support
options MFS #Memory Filesystem
options MD_ROOT #MD is a potential root device
options NFS #Network Filesystem
options NFS_ROOT #NFS usable as root device, NFS required
options MSDOSFS #MSDOS Filesystem
options CD9660 #ISO 9660 Filesystem
options DEVFS #Device Filesystem
options PROCFS #Process filesystem
options COMPAT_43 #Compatible with BSD 4.3 [KEEP THIS!]
options SCSI_DELAY=15000 #Delay (in ms) before probing SCSI
options UCONSOLE #Allow users to grab the console
options USERCONFIG #boot -c editor
options VISUAL_USERCONFIG #visual boot -c editor
options KTRACE #ktrace(1) support
options SYSVSHM #SYSV-style shared memory
options SYSVMSG #SYSV-style message queues
options SYSVSEM #SYSV-style semaphores
options P1003_1B #Posix P1003_1B real-time extensions
options _KPOSIX_PRIORITY_SCHEDULING
options KBD_INSTALL_CDEV # install a CDEV entry in /dev
# To make an SMP kernel, the next two are needed
options SMP # Symmetric MultiProcessor Kernel
options APIC_IO # Symmetric (APIC) I/O
device isa
device eisa
device pci
# Floppy drives
device fdc
# ATA and ATAPI devices
device ata
device atadisk # ATA disk drives
device atapicd # ATAPI CDROM drives
device atapifd # ATAPI floppy drives
device atapist # ATAPI tape drives
options ATA_STATIC_ID #Static device numbering
# SCSI Controllers
device ahb # EISA AHA1742 family
device ahc # AHA2940 and onboard AIC7xxx devices
device amd # AMD 53C974 (Tekram DC-390(T))
device isp # Qlogic family
#device ncr # NCR/Symbios Logic
device sym # NCR/Symbios Logic (newer chipsets + those of `ncr')
device adv # Advansys SCSI adapters
device adw # Advansys wide SCSI adapters
device aha # Adaptec 154x SCSI adapters
device aic # Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
device bt # Buslogic/Mylex MultiMaster SCSI adapters
device ncv # NCR 53C500
device nsp # Workbit Ninja SCSI-3
device stg # TMC 18C30/18C50
# RAID controllers interfaced to the SCSI subsystem
device asr # DPT SmartRAID V, VI and Adaptec SCSI RAID
device dpt # DPT Smartcache III, IV - See NOTES for options!
device mly # Mylex AcceleRAID/eXtremeRAID
# SCSI peripherals
device scbus # SCSI bus (required)
device da # Direct Access (disks)
device sa # Sequential Access (tape etc)
device cd # CD
device pass # Passthrough device (direct SCSI access)
# RAID controllers
device aac # Adaptec FSA RAID
device amr # AMI MegaRAID
device ida # Compaq Smart RAID
device mlx # Mylex DAC960 family
device twe # 3ware ATA RAID
# atkbdc0 controls both the keyboard and the PS/2 mouse
device atkbdc 1 # At keyboard controller
device atkbd # at keyboard
device psm # psm mouse
device vga # VGA screen
# splash screen/screen saver
device splash
# syscons is the default console driver, resembling an SCO console
device sc 1
# Enable this for the pcvt (VT220 compatible) console driver
#device vt
#options XSERVER # support for X server on a vt console
#options FAT_CURSOR # start with block cursor
# If you have a ThinkPAD, uncomment this along with the rest of the PCVT lines
#options PCVT_SCANSET=2 # IBM keyboards are non-std
# Floating point support - do not disable.
device npx
# Power management support (see NOTES for more options)
device apm
# Add suspend/resume support for the i8254.
device pmtimer
# Audio support
device pcm
# PCCARD (PCMCIA) support
device card # pccard bus
device pcic # PCMCIA bridge
# Serial (COM) ports
device sio # 8250, 16[45]50 based serial ports
# Parallel port
device ppc
device ppbus # Parallel port bus (required)
device lpt # Printer
device plip # TCP/IP over parallel
device ppi # Parallel port interface device
#device vpo # Requires scbus and da
# PCI Ethernet NICs.
device de # DEC/Intel DC21x4x (``Tulip'')
device vx # 3Com 3c590, 3c595 (``Vortex'')
device wx # Intel Gigabit Ethernet Card (``Wiseman'')
# PCI Ethernet NICs that use the common MII bus controller code.
# NOTE: Be sure to keep the 'device miibus' line in order to use these NICs!
device miibus # MII bus support
device dc # DEC/Intel 21143 and various workalikes
device fxp # Intel EtherExpress PRO/100B (82557, 82558)
device pcn # AMD Am79C79x PCI 10/100 NICs
device rl # RealTek 8129/8139
device sf # Adaptec AIC-6915 (``Starfire'')
device sis # Silicon Integrated Systems SiS 900/SiS 7016
device ste # Sundance ST201 (D-Link DFE-550TX)
device tl # Texas Instruments ThunderLAN
device tx # SMC EtherPower II (83c170 ``EPIC'')
device vr # VIA Rhine, Rhine II
device wb # Winbond W89C840F
device xl # 3Com 3c90x (``Boomerang'', ``Cyclone'')
# ISA Ethernet NICs. pccard nics included.
device cs # Crystal Semiconductor CS89x0 NIC
# 'device ed' requires 'device miibus'
device ed # NE[12]000, SMC Ultra, 3c503, DS8390 cards
device ex # Intel EtherExpress Pro/10 and Pro/10+
device ep # Etherlink III based cards
device fe # Fujitsu MB8696x based cards
device sn # SMC's 9000 series of ethernet chips
device xe # Xircom pccard ethernet
# The probe order of these is presently determined by i386/isa/isa_compat.c.
#device ie
#device le
device lnc
# Wireless NIC cards
device an # Aironet 4500/4800 802.11 wireless NICs.
device awi # BayStack 660 and others
device wi # WaveLAN/IEEE 802.11 wireless NICs.
#device wl # Older non 802.11 Wavelan wireless NIC.
# Pseudo devices - the number indicates how many units to allocate.
device random # Entropy device
device loop # Network loopback
device ether # Ethernet support
device sl # Kernel SLIP
device ppp 1 # Kernel PPP
device tun # Packet tunnel.
device pty # Pseudo-ttys (telnet etc)
device md # Memory "disks"
device gif 4 # IPv6 and IPv4 tunneling
device faith 1 # IPv6-to-IPv4 relaying (translation)
# The `bpf' device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
device bpf # Berkeley packet filter
# USB support
device uhci # UHCI PCI->USB interface
device ohci # OHCI PCI->USB interface
device usb # USB Bus (required)
#device udbp # USB Double Bulk Pipe devices
device ugen # Generic
device uhid # "Human Interface Devices"
device ukbd # Keyboard
device ulpt # Printer
device umass # Disks/Mass storage - Requires scbus and da
device ums # Mouse
device urio # Diamond Rio 500 MP3 player
device uscanner # Scanners
# USB Ethernet, requires mii
device aue # ADMtek USB ethernet
device cue # CATC USB ethernet
device kue # Kawasaki LSI USB ethernet
device sbc
options INVARIANTS
options INVARIANT_SUPPORT
options IPSEC
options IPSEC_ESP
options DDB
options DDB_UNATTENDED
options WITNESS
options DIAGNOSTIC
ichotolot#
Script done on Thu Apr 5 01:17:50 2001
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