I know there is something about loop device hangs in the 2.4 TODO list and I don't know if that is supposed to be fixed. If this BUG is known, please appreciate [1.] One line summary of the problem: [240-ac8] loop device hangs and sync does not return any more [2.] Full description of the problem/report: When I copy data to a ext2 filesystem mounted via loop0 the 'cp' command stops after a while. The system is not dead but very unusuable and I can't reboot because 'sync' is not working. I am in single user mode on a 2way Pentium 166 w/o mmx SMP system. 2.2.X is stable. The loop dev is compiled as a module. I tried with 'noapic', 'maxcpus=1' and combination of both. I have not tried a UP kernel. Same happens with 2.4.0-prerelease. Copying (a lot of) data between "normal" mounted filesystems works fine. [3.] Keywords (i.e., modules, networking, kernel): loop device, sync, module, SMP. [4.] Kernel version (from /proc/version): Linux version 2.4.0-ac8 ([EMAIL PROTECTED]) (gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)) #7 SMP Sat Jan 13 14:05:38 CET 2001 [5.] Output of Oops.. message (if applicable) with symbolic information not available [6.] A small shell script or example program which triggers the problem (if possible) dd if=/dev/zero of=file bs=1M count=500 mke2fs file mount -o loop=/dev/loop0 file /mnt/loop cd $_ cp -av /bin/ /etc/ /sbin/ . mkdir usr && cp -av /usr/bin usr/ [7.] Environment [7.1.] Software (add the output of the ver_linux script here) Kernel modules 2.4.1 Gnu C egcs-2.91.66 Gnu Make 3.77 Binutils 2.10.0.18 Linux C Library 2.1.2 Dynamic linker ldd (GNU libc) 2.1.2 Procps 2.0.6 Mount 2.10r Net-tools 1.53 Console-tools 1999.03.02 Sh-utils 2.0 Modules Loaded loop 3c59x sb sb_lib uart401 sound soundcore [7.2.] Processor information (from /proc/cpuinfo): processor : 0 vendor_id : GenuineIntel cpu family : 5 model : 2 model name : Pentium 75 - 200 stepping : 12 cpu MHz : 167.048 fdiv_bug : no hlt_bug : no f00f_bug : yes coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr mce cx8 apic bogomips : 333.41 processor : 1 ... (same) [7.3.] Module information (from /proc/modules): loop 7808 0 (unused) 3c59x 24672 1 (autoclean) sb 7712 0 (autoclean) sb_lib 36192 0 (autoclean) [sb] uart401 6640 0 (autoclean) [sb_lib] sound 63024 0 (autoclean) [sb_lib uart401] soundcore 4208 5 (autoclean) [sb_lib sound] [7.4.] Loaded driver and hardware information I am on an SCSI only system with aic7xxx and 2 4Gig IBM UW disk. 0000-001f : dma1 0020-003f : pic1 0040-005f : timer 0060-006f : keyboard 0070-007f : rtc 0080-008f : dma page reg 00a0-00bf : pic2 00c0-00df : dma2 00f0-00ff : fpu 0220-022f : soundblaster 02f8-02ff : serial(auto) 0330-0333 : MPU-401 UART 03c0-03df : vga+ 03c0-03df : matrox 03f8-03ff : serial(auto) 0cf8-0cff : PCI conf1 6000-60ff : Adaptec AIC-7880U 6000-60fe : aic7xxx 6400-647f : 3Com Corporation 3c905B 100BaseTX [Cyclone] 6400-647f : eth0 f000-f00f : Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II] [X.] Other notes, patches, fixes, workarounds: For what it's worth: Data is copied from sda1 to sdb1 where the loop device is located I have a lot of NMI interrupts, nearly twice as much as from the timer. Same is true for LOC. Sometimes I even have some ERR but usually not more than 10. When using sysrq to do an emergency sync and a killall I get: (from memory) NMI Watchdog detected LOOKUP on CPU0 and the calltrace (resolved) do_exit do_signal do_pollfd signal_return Thanks in advance Tilmann - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/