I installed SLF 5.4 on a Dell Precision M4500 and it has generally performed well except that it crashes with a kernel panic an average about once a day. I enabled the memory dump on kernel panic and although default kernel image doesn't have debugging symbols, I can dump the strings in the vmcore file and always find the following: ... <3>ehci_hcd 0000:00:1d.0: fatal error <1>Unable to handle kernel NULL pointer dereference at 0000000000000088 RIP: <1> [<ffffffff88000e07>] :ehci_hcd:end_unlink_async+0x2f/0x108 <4>PGD 1280d1067 PUD 12dc82067 PMD 0 <0>Oops: 0002 [1] SMP <1>last sysfs file: /devices/pci0000:00/0000:00:00.0/irq <4>CPU 7 ... <4>Call Trace: <4> <IRQ> [<ffffffff88000fec>] :ehci_hcd:unlink_async+0x19/0x58 <4> [<ffffffff8800135c>] :ehci_hcd:qh_completions+0x331/0x344 <4> [<ffffffff8800181d>] :ehci_hcd:ehci_work+0xad/0x6d1 <4> [<ffffffff80079374>] end_level_ioapic_vector+0x9/0x16 <4> [<ffffffff800baff5>] __do_IRQ+0xeb/0x103 <4> [<ffffffff8800031b>] :ehci_hcd:handshake+0x38/0x49 <4> [<ffffffff8800463c>] :ehci_hcd:ehci_irq+0x145/0x15d <4> [<ffffffff801f7623>] usb_hcd_irq+0x27/0x55 <4> [<ffffffff80010c3a>] handle_IRQ_event+0x51/0xa6 <4> [<ffffffff800bafae>] __do_IRQ+0xa4/0x103 <4> [<ffffffff80012443>] __do_softirq+0x89/0x133 <4> [<ffffffff8006ca0d>] do_IRQ+0xe7/0xf5 <4> [<ffffffff8005d615>] ret_from_intr+0x0/0xa <4> <EOI> [<ffffffff80030358>] unix_poll+0x0/0x99 <4> [<ffffffff800118e9>] do_select+0x261/0x462 <4> [<ffffffff800118d9>] do_select+0x251/0x462 <4> [<ffffffff8001ebd8>] __pollwait+0x0/0xe2 ... Are there any kernel updates or command line options that I am missing that might fix this? It also hangs occasionally when starting up when it checks for hardware updates, but I can deal with that issue separately. Here is some system info if it helps: $ yum list kernel kernel.x86_64 2.6.18-194.26.1.el5 installed $ uname -a Linux mjones-laptop2 2.6.18-194.26.1.el5 #1 SMP Tue Nov 9 12:46:16 EST 2010 x86_64 x86_64 x86_64 GNU/Linux $ /sbin/lsusb Bus 001 Device 001: ID 0000:0000 Bus 001 Device 002: ID 8087:0020 Bus 002 Device 001: ID 0000:0000 Bus 002 Device 003: ID 046d:c01a Logitech, Inc. M-BQ85 Optical Wheel Mouse Bus 002 Device 005: ID 0a5c:5800 Broadcom Corp. BCM5880 Secure Applications Processor Bus 002 Device 004: ID 413c:8187 Dell Computer Corp. Bus 002 Device 002: ID 8087:0020 $ demsg Linux version 2.6.18-194.26.1.el5 ([log in to unmask]) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Tue Nov 9 12:46:16 EST 2010 Command line: ro root=/dev/sdb8 crashkernel=64M@16M rhgb quiet .. SMP: Allowing 8 CPUs, 0 hotplug CPUs Built 1 zonelists. Total pages: 1027656 Kernel command line: ro root=/dev/sdb8 crashkernel=64M@16M rhgb quiet .. Thanks, Matthew. ------------------------------------------------------------------------ Matthew Jones Office: PHYS 378 Department of Physics, Purdue University Office phone: 765-496-2464 525 Northwestern Ave Fermilab Phone: 630-840-2859 West Lafayette, IN 47907-2036 e-mail: [log in to unmask]