While working on a patch to remove the SN dependencies from the ioc4 driver, I ran across the included oops in the IDE code. I believe the problem is that HWIF(drive) is NULL in SELECT_DRIVE. This seems to be confirmed by the value of r10 in the oops output, which contains &(HWIF(drive)->intrproc) at the moment of the oops. If my reading of the IDE code is correct (I'm no expert, to be sure), the "hwif" field of an ide_drive_t is initialized in init_irq() in ide-probe.c. However, this code has not been called yet. The structure of function calls as-coded is: probe_hwif_init_with_fixup probe_hwif wait_hwif_ready SELECT_DRIVE hwif_init init_irq So, unless I'm missing something, there seems to be a use of an (ide_drive_t*)->hwif field (in SELECT_DRIVE()) before it is initialized (in init_irq()). Thanks, Brent Casavant Unable to handle kernel NULL pointer dereference (address 0000000000000840) swapper[1]: Oops 8813272891392 [1] Modules linked in: Pid: 1, CPU 0, comm: swapper psr : 00001010085a6010 ifs : 8000000000000287 ip : [<a0000001005262d0>] Not tainted ip is at SELECT_DRIVE+0x30/0xe0 unat: 0000000000000000 pfs : 000000000000040a rsc : 0000000000000003 rnat: 9ffffffff6000000 bsps: 000000000000fffe pr : 000000000000a581 ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c8a70433f csd : 0000000000000000 ssd : 0000000000000000 b0 : a00000010052c670 b6 : a00000010051bec0 b7 : a0000001004cbe40 f6 : 1003e0000000138800000 f7 : 1003e431bde82d7b634db f8 : 1003e0000000001312d00 f9 : 1003e00000004a817c800 f10 : 1003e00000000000003e8 f11 : 1003e0000000000000000 r1 : a000000100eb6ef0 r2 : a000000100ccfae8 r3 : a000000100ccfae8 r8 : 0000000000000000 r9 : 0000000000000000 r10 : 0000000000000840 r11 : 0000000000000000 r12 : e00000307a6c7d20 r13 : e00000307a6c0000 r14 : 00000000000000ff r15 : 0000000000000050 r16 : 0000000000000000 r17 : e00000307a279398 r18 : 0000000000000000 r19 : 0000000000000020 r20 : e000003003110000 r21 : 0000000000000000 r22 : 0000000000000000 r23 : 000000000000000f r24 : e00000307a3da480 r25 : ffffffffffff4230 r26 : e0000030030a4000 r27 : 0000000000000000 r28 : e00000307a279390 r29 : e00000307a279380 r30 : 0000000000000000 r31 : e000003003105238 Call Trace: [<a0000001000129c0>] show_stack+0x40/0xa0 sp=e00000307a6c78d0 bsp=e00000307a6c0fe0 [<a0000001000132c0>] show_regs+0x840/0x880 sp=e00000307a6c7aa0 bsp=e00000307a6c0f88 [<a000000100034c90>] die+0x250/0x320 sp=e00000307a6c7aa0 bsp=e00000307a6c0f40 [<a000000100058990>] ia64_do_page_fault+0x930/0xa60 sp=e00000307a6c7ac0 bsp=e00000307a6c0ef0 [<a00000010000bb40>] ia64_leave_kernel+0x0/0x290 sp=e00000307a6c7b50 bsp=e00000307a6c0ef0 [<a0000001005262d0>] SELECT_DRIVE+0x30/0xe0 sp=e00000307a6c7d20 bsp=e00000307a6c0eb8 [<a00000010052c670>] wait_hwif_ready+0x90/0x1a0 sp=e00000307a6c7d20 bsp=e00000307a6c0e78 [<a00000010052e130>] probe_hwif+0x1f0/0x1020 sp=e00000307a6c7d20 bsp=e00000307a6c0e08 [<a000000100530830>] probe_hwif_init_with_fixup+0x30/0x1a0 sp=e00000307a6c7d20 bsp=e00000307a6c0dd8 [<a0000001005309d0>] probe_hwif_init+0x30/0x60 sp=e00000307a6c7d20 bsp=e00000307a6c0db8 [<a00000010051be50>] ioc4_ide_attach_one+0x570/0x5e0 sp=e00000307a6c7d20 bsp=e00000307a6c0d58 [<a0000001004ef990>] ioc4_register_submodule+0xd0/0x200 sp=e00000307a6c7d30 bsp=e00000307a6c0d30 [<a00000010051a580>] ioc4_ide_init+0x20/0x40 sp=e00000307a6c7d30 bsp=e00000307a6c0d18 [<a000000100009720>] init+0x420/0x840 sp=e00000307a6c7d30 bsp=e00000307a6c0ce8 [<a000000100010f70>] kernel_thread_helper+0xd0/0x100 sp=e00000307a6c7e30 bsp=e00000307a6c0cc0 [<a000000100009140>] start_kernel_thread+0x20/0x40 sp=e00000307a6c7e30 bsp=e00000307a6c0cc0 <0>Kernel panic - not syncing: Attempted to kill init! -- Brent Casavant All music is folk music. I ain't bcasavan@xxxxxxx never heard a horse sing a song. Silicon Graphics, Inc. -- Louis Armstrong - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html