Re: Oops in __free_pages_ok (pre7-1) (Long) (backtrace)

[Rajagopal Ananthanarayanan <ananth@sgi.com>]

Linus Torvalds wrote:
> 
> On 2 May 2000, Juan J. Quintela wrote:
> > Hi
> >         several people have reported Oops in __free_pages_ok, after a
> > BUG() in page_alloc.h.  This happens in 2.3.99-pre[67].  The BUGs are:
> 
> I'd like ot know what the back-trace for those reports are?
> 
> I'm not against getting rid of the PageSwapEntry logic (it's complication
> for not very much gain), but I'd like to understand this more..


Following please find information about one of the BUG() in __free_pages_ok();
I'm re-sending the messages I sent to linux-kernel eariler last week:

-------------

I ran into a BUG in __free_pages_ok which checks:

----------
        if (PageSwapCache(page))
                BUG();
----------

The  call to free the page was from try_to_swap_out():

----------
        /*
         * Is the page already in the swap cache? If so, then
         * we can just drop our reference to it without doing
         * any IO - it's already up-to-date on disk.
         *
         * Return 0, as we didn't actually free any real
         * memory, and we should just continue our scan.
         */
        if (PageSwapCache(page)) {
                entry.val = page->index;
                swap_duplicate(entry);
                set_pte(page_table, swp_entry_to_pte(entry));
drop_pte:
                vma->vm_mm->rss--;
                flush_tlb_page(vma, address);
                __free_page(page);
                goto out_failed;
        }
-----------

The entire trace from kdb is as follows (XXX = unknown):

----------
XXXXXXXXXX XXXXXXXXXX  __free_pages_ok(XXXX)
0xc35d5d9c 0xc013543c  try_to_swap_out+0xc8( 0xc179dc20, 0x43589000, 0xc2963624,
0x5,
0xc179dc20 )
0xc35d5dd8 0xc0135710  swap_out_vma+0x11c( 0xc179dc20, 0x432d4000, 0x5, 0xc02c7c68,
0xc3256520 )
0xc35d5df8 0xc01357ee  swap_out_mm+0x7e( 0xc3256520, 0x5, 0x4, 0x6, 0x5 )
0xc35d5e24 0xc01359de  swap_out+0x176( 0x6, 0x5, 0xc35d4000, 0xc02d0890, 0x5 )
0xc35d5e40 0xc0135b31  do_try_to_free_pages+0x89( 0x5, 0xc02d06b8, 0xc02d06b8,
0xc35d5e78,
0xc013666b )
0xc35d5e54 0xc0135d17  try_to_free_pages+0x2b( 0x5, 0xc02d06b8, 0xc02d0898, 0x0,
0xc02d088c )
0xc35d5e78 0xc013666b  zone_balance_memory+0x63( 0xc02d088c, 0xc35d4000, 0x0,
0x5b5f00 )
0xc35d5e98 0xc0136724  __alloc_pages+0x80( 0xc35d4000, 0x0, 0xc35d4000 )
0xc35d5eac 0xc0136dbe  read_swap_cache_async+0x62( 0x5b5f00, 0x1, 0x5b5f00,
0x5b5f00,
0xc13919c4 )
0xc35d5ecc 0xc012889b  do_swap_page+0x97( 0xc35d4000, 0xc179dc20, 0x45671fff,
0xc13919c4,
0x5b5f00 )
0xc35d5efc 0xc0128ce7  handle_mm_fault+0x13b( 0xc35d4000, 0xc179dc20, 0x45671fff,
0x0,
0xc35d4000 )
0xc35d5fb4 0xc011513e  do_page_fault+0x18e
[1]more>
0xbffff540 0xc010a681  error_code+0x2d 
-------------

I have a kdb helper function which prints out some of the fields in the page,
and also below is the hex dump of the "struct page"

----------
  [1]kdb> page 0xc1002de0
struct page at 0xc1002de0
  next 0xc1042ee0 prev 0xc101e900 addr space 0xc02d0520 index 557568
  count 1 flags PG_uptodate PG_swap_cache PG_swap_entry virtual 0xc0092000
  buffers 0x00000000  block_map 00000000000000000000000000000000
    [ ... ] 
                         
c1002de0: c1042ee0 c101e900 c02d0520 00088200  a..A.e.A .-A....
c1002df0: 00000000 00000001 00000a08 c1042efc  ............u..A
c1002e00: c101e91c 00000000 dead4ead c1002e0c  .e.A....-N-TH...A
c1002e10: c1002e0c c1002e14 c02f3b3f c1150e5c  ...A...A?;/A\..A
c1002e20: 00000000 c0092000 c02d0600 00000000  ..... .A..-A.... 
---------------------


Question: Is this a problem in the reference count on the page?
If indeed the page can be freed by the call in try_to_swap_out,
then the test in __free_pages_ok will trigger every time this path
is taken. Any one have ideas as to what's wrong?

BTW, the above happened during a relatively normal operation of
using 'diff'. Don't know if it reproducible.
----------------------

As Jeff G. pointed out in another mail, I left out some
important information. If you need more info., please let me know.

(1) this is with kernel version 2.3.99-pre2 with some XFS changes.
(2) I have a 2 CPU X-86 box with 64MB memory.

Here's the .config used to build the kernel:

-----------
#
# Automatically generated by make menuconfig: don't edit
#
CONFIG_X86=y
CONFIG_ISA=y
CONFIG_UID16=y

#
# Code maturity level options
#
CONFIG_EXPERIMENTAL=y

#
# Processor type and features
#
# CONFIG_M386 is not set
# CONFIG_M486 is not set
# CONFIG_M586 is not set
# CONFIG_M586TSC is not set
CONFIG_M686=y
# CONFIG_MK6 is not set
# CONFIG_MK7 is not set
CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
CONFIG_X86_TSC=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_PGE=y
# CONFIG_MICROCODE is not set
CONFIG_NOHIGHMEM=y
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
# CONFIG_MATH_EMULATION is not set
# CONFIG_MTRR is not set
CONFIG_SMP=y

#
# Loadable module support
#
CONFIG_MODULES=y
CONFIG_MODVERSIONS=y
CONFIG_KMOD=y

#
# General setup
#
CONFIG_NET=y
# CONFIG_VISWS is not set
CONFIG_X86_IO_APIC=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_PCI=y
# CONFIG_PCI_GOBIOS is not set
# CONFIG_PCI_GODIRECT is not set
CONFIG_PCI_GOANY=y
CONFIG_PCI_BIOS=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_NAMES=y
# CONFIG_MCA is not set
# CONFIG_HOTPLUG is not set
CONFIG_SYSVIPC=y
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_SYSCTL is not set
CONFIG_KCORE_ELF=y
# CONFIG_KCORE_AOUT is not set
CONFIG_BINFMT_AOUT=m
CONFIG_BINFMT_ELF=y
CONFIG_BINFMT_MISC=m
# CONFIG_PM is not set
# CONFIG_ACPI is not set
# CONFIG_APM is not set

#
# Parallel port support
#
# CONFIG_PARPORT is not set

#
# Plug and Play configuration
#
# CONFIG_PNP is not set
# CONFIG_ISAPNP is not set

#
# Block devices
#
CONFIG_BLK_DEV_FD=m
# CONFIG_BLK_DEV_XD is not set
# CONFIG_PARIDE is not set
# CONFIG_BLK_CPQ_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_LOOP is not set
# CONFIG_BLK_DEV_NBD is not set
# CONFIG_BLK_DEV_MD is not set
# CONFIG_BLK_DEV_RAM is not set

#
# Networking options
#
CONFIG_PACKET=m
# CONFIG_PACKET_MMAP is not set
# CONFIG_NETLINK is not set
# CONFIG_NETFILTER is not set
# CONFIG_FILTER is not set
CONFIG_UNIX=y
CONFIG_INET=y
# CONFIG_IP_MULTICAST is not set
# CONFIG_IP_ADVANCED_ROUTER is not set
# CONFIG_IP_PNP is not set
# CONFIG_IP_ROUTER is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
# CONFIG_IP_ALIAS is not set
# CONFIG_SYN_COOKIES is not set
CONFIG_SKB_LARGE=y
# CONFIG_IPV6 is not set
# CONFIG_KHTTPD is not set
# CONFIG_ATM is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_DECNET is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_BRIDGE is not set
# CONFIG_LLC is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set
# CONFIG_NET_FASTROUTE is not set
# CONFIG_NET_HW_FLOWCONTROL is not set

#
# QoS and/or fair queueing
#
# CONFIG_NET_SCHED is not set

#
# Telephony Support
#
# CONFIG_PHONE is not set
# CONFIG_PHONE_IXJ is not set

#
# ATA/IDE/MFM/RLL support
#
# CONFIG_IDE is not set
# CONFIG_BLK_DEV_IDE_MODES is not set
# CONFIG_BLK_DEV_HD is not set

#
# SCSI support
#
CONFIG_SCSI=y
CONFIG_BLK_DEV_SD=y
CONFIG_SD_EXTRA_DEVS=40
# CONFIG_CHR_DEV_ST is not set
# CONFIG_BLK_DEV_SR is not set
# CONFIG_CHR_DEV_SG is not set
CONFIG_SCSI_DEBUG_QUEUES=y
CONFIG_SCSI_MULTI_LUN=y
CONFIG_SCSI_CONSTANTS=y
# CONFIG_SCSI_LOGGING is not set

#
# SCSI low-level drivers
#
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_7000FASST is not set
# CONFIG_SCSI_ACARD is not set
CONFIG_SCSI_AHA152X=m
# CONFIG_SCSI_AHA1542 is not set
CONFIG_SCSI_AHA1740=m
CONFIG_SCSI_AIC7XXX=y
# CONFIG_AIC7XXX_TCQ_ON_BY_DEFAULT is not set
CONFIG_AIC7XXX_CMDS_PER_DEVICE=8
# CONFIG_AIC7XXX_PROC_STATS is not set
CONFIG_AIC7XXX_RESET_DELAY=5
# CONFIG_SCSI_IPS is not set
# CONFIG_SCSI_ADVANSYS is not set
# CONFIG_SCSI_IN2000 is not set
# CONFIG_SCSI_AM53C974 is not set
# CONFIG_SCSI_MEGARAID is not set
# CONFIG_SCSI_BUSLOGIC is not set
# CONFIG_SCSI_DTC3280 is not set
# CONFIG_SCSI_EATA is not set
# CONFIG_SCSI_EATA_DMA is not set
# CONFIG_SCSI_EATA_PIO is not set
# CONFIG_SCSI_FUTURE_DOMAIN is not set
# CONFIG_SCSI_GDTH is not set
# CONFIG_SCSI_GENERIC_NCR5380 is not set
# CONFIG_SCSI_INITIO is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_NCR53C406A is not set
# CONFIG_SCSI_SYM53C416 is not set
# CONFIG_SCSI_SIM710 is not set
# CONFIG_SCSI_NCR53C7xx is not set
# CONFIG_SCSI_NCR53C8XX is not set
CONFIG_SCSI_SYM53C8XX=m
CONFIG_SCSI_NCR53C8XX_DEFAULT_TAGS=4
CONFIG_SCSI_NCR53C8XX_MAX_TAGS=32
CONFIG_SCSI_NCR53C8XX_SYNC=20
# CONFIG_SCSI_NCR53C8XX_PROFILE is not set
# CONFIG_SCSI_NCR53C8XX_IOMAPPED is not set
# CONFIG_SCSI_NCR53C8XX_PQS_PDS is not set
# CONFIG_SCSI_NCR53C8XX_SYMBIOS_COMPAT is not set
# CONFIG_SCSI_PAS16 is not set
# CONFIG_SCSI_PCI2000 is not set
# CONFIG_SCSI_PCI2220I is not set
# CONFIG_SCSI_PSI240I is not set
# CONFIG_SCSI_QLOGIC_FAS is not set
# CONFIG_SCSI_QLOGIC_ISP is not set
CONFIG_SCSI_QLOGIC_FC=m
# CONFIG_SCSI_QLOGIC_1280 is not set
# CONFIG_SCSI_SEAGATE is not set
# CONFIG_SCSI_DC390T is not set
# CONFIG_SCSI_T128 is not set
# CONFIG_SCSI_U14_34F is not set
# CONFIG_SCSI_ULTRASTOR is not set
# CONFIG_SCSI_DEBUG is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_IEEE1394 is not set

#
# I2O device support
#
# CONFIG_I2O is not set
# CONFIG_I2O_PCI is not set
# CONFIG_I2O_BLOCK is not set
# CONFIG_I2O_LAN is not set
# CONFIG_I2O_SCSI is not set
# CONFIG_I2O_PROC is not set

#
# Network device support
#
CONFIG_NETDEVICES=y

#
# ARCnet devices
#
# CONFIG_ARCNET is not set
CONFIG_DUMMY=m
# CONFIG_BONDING is not set
# CONFIG_EQUALIZER is not set
# CONFIG_NET_SB1000 is not set

#
# Ethernet (10 or 100Mbit)
#
CONFIG_NET_ETHERNET=y
CONFIG_NET_VENDOR_3COM=y
# CONFIG_EL1 is not set
# CONFIG_EL2 is not set
# CONFIG_ELPLUS is not set
# CONFIG_EL16 is not set
# CONFIG_EL3 is not set
# CONFIG_3C515 is not set
CONFIG_VORTEX=m
CONFIG_LANCE=m
# CONFIG_NET_VENDOR_SMC is not set
# CONFIG_NET_VENDOR_RACAL is not set
# CONFIG_AT1700 is not set
# CONFIG_DEPCA is not set
# CONFIG_NET_ISA is not set
CONFIG_NET_PCI=y
CONFIG_PCNET32=m
# CONFIG_ADAPTEC_STARFIRE is not set
# CONFIG_AC3200 is not set
# CONFIG_APRICOT is not set
# CONFIG_CS89x0 is not set
# CONFIG_DE4X5 is not set
# CONFIG_TULIP is not set
# CONFIG_DGRS is not set
# CONFIG_DM9102 is not set
# CONFIG_EEPRO100 is not set
# CONFIG_LNE390 is not set
# CONFIG_NE3210 is not set
# CONFIG_NE2K_PCI is not set
# CONFIG_RTL8129 is not set
# CONFIG_8139TOO is not set
# CONFIG_SIS900 is not set
# CONFIG_TLAN is not set
# CONFIG_VIA_RHINE is not set
# CONFIG_ES3210 is not set
# CONFIG_EPIC100 is not set
# CONFIG_NET_POCKET is not set

#
# Ethernet (1000 Mbit)
#
# CONFIG_YELLOWFIN is not set
# CONFIG_ACENIC is not set
# CONFIG_SK98LIN is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
# CONFIG_PPP is not set
# CONFIG_SLIP is not set

#
# Wireless LAN (non-hamradio)
#
# CONFIG_NET_RADIO is not set

#
# Token Ring devices
#
# CONFIG_TR is not set
# CONFIG_NET_FC is not set
# CONFIG_RCPCI is not set
# CONFIG_SHAPER is not set

#
# Wan interfaces
#
# CONFIG_WAN is not set

#
# Amateur Radio support
#
# CONFIG_HAMRADIO is not set

#
# IrDA (infrared) support
#
# CONFIG_IRDA is not set

#
# ISDN subsystem
#
# CONFIG_ISDN is not set

#
# Old CD-ROM drivers (not SCSI, not IDE)
#
# CONFIG_CD_NO_IDESCSI is not set

#
# Character devices
#
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_SERIAL=y
CONFIG_SERIAL_CONSOLE=y
# CONFIG_SERIAL_EXTENDED is not set
# CONFIG_SERIAL_NONSTANDARD is not set
CONFIG_UNIX98_PTYS=y
CONFIG_UNIX98_PTY_COUNT=256

#
# I2C support
#
# CONFIG_I2C is not set

#
# Mice
#
# CONFIG_BUSMOUSE is not set
CONFIG_MOUSE=y
CONFIG_PSMOUSE=y
CONFIG_82C710_MOUSE=y
# CONFIG_PC110_PAD is not set

#
# Joysticks
#
# CONFIG_JOYSTICK is not set
# CONFIG_QIC02_TAPE is not set

#
# Watchdog Cards
#
# CONFIG_WATCHDOG is not set
CONFIG_PROFILING=y
# CONFIG_NVRAM is not set
# CONFIG_RTC is not set

#
# Video For Linux
#
# CONFIG_VIDEO_DEV is not set
# CONFIG_DTLK is not set
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set

#
# Ftape, the floppy tape device driver
#
# CONFIG_FTAPE is not set
CONFIG_DRM=y
# CONFIG_DRM_TDFX is not set
# CONFIG_DRM_GAMMA is not set
# CONFIG_AGP is not set

#
# USB support
#
# CONFIG_USB is not set

#
# File systems
#
# CONFIG_QUOTA is not set
CONFIG_AUTOFS_FS=m
CONFIG_AUTOFS4_FS=m
# CONFIG_ADFS_FS is not set
# CONFIG_AFFS_FS is not set
# CONFIG_HFS_FS is not set
# CONFIG_BFS_FS is not set
# CONFIG_FAT_FS is not set
# CONFIG_MSDOS_FS is not set
# CONFIG_UMSDOS_FS is not set
# CONFIG_VFAT_FS is not set
# CONFIG_EFS_FS is not set
# CONFIG_CRAMFS is not set
CONFIG_ISO9660_FS=m
# CONFIG_JOLIET is not set
# CONFIG_MINIX_FS is not set
# CONFIG_NTFS_FS is not set
# CONFIG_HPFS_FS is not set
CONFIG_PROC_FS=y
# CONFIG_DEVFS_FS is not set
# CONFIG_DEVFS_DEBUG is not set
CONFIG_DEVPTS_FS=y
# CONFIG_QNX4FS_FS is not set
# CONFIG_ROMFS_FS is not set
CONFIG_EXT2_FS=y
# CONFIG_SYSV_FS is not set
# CONFIG_UDF_FS is not set
# CONFIG_UFS_FS is not set
CONFIG_XFS_FS=m
CONFIG_PAGE_BUF=y
CONFIG_PAGE_BUF_LOCKING=y
CONFIG_AVL=y
# CONFIG_PAGE_BUF_META is not set
# CONFIG_XFS_VNODE_TRACING is not set
CONFIG_AVL=y
# CONFIG_XFS_ARCH_MIPS is not set
CONFIG_XFS_ARCH_NATIVE=y
# CONFIG_XFS_ARCH_MULTI is not set

#
# Network File Systems
#
# CONFIG_CODA_FS is not set
CONFIG_NFS_FS=m
# CONFIG_ROOT_NFS is not set
# CONFIG_NFSD is not set
CONFIG_SUNRPC=m
CONFIG_LOCKD=m
# CONFIG_SMB_FS is not set
# CONFIG_NCP_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y
# CONFIG_NLS is not set

#
# Console drivers
#
CONFIG_VGA_CONSOLE=y
# CONFIG_VIDEO_SELECT is not set
# CONFIG_MDA_CONSOLE is not set

#
# Frame-buffer support
#
# CONFIG_FB is not set

#
# Sound
#
# CONFIG_SOUND is not set

#
# Kernel hacking
#
# CONFIG_MAGIC_SYSRQ is not set
# CONFIG_LOCKMETER is not set
CONFIG_KDB=y
CONFIG_KDB_FRAMEPTR=y
CONFIG_KDB_STBSIZE=13500
CONFIG_MCOUNT=y
CONFIG_PROF_FRAME_PTR=y

-- 
--------------------------------------------------------------------------
Rajagopal Ananthanarayanan ("ananth")
Member Technical Staff, SGI.
--------------------------------------------------------------------------
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux.eu.org/Linux-MM/