Re: LOR (drm,acpi)

Alex Vasylenko wrote:
> The following was reported when leaving X on FreeBSD 5.2-CURRENT #6: Sat Aug 14 09:23:46 EDT 2004:
> 
> lock order reversal
> 1st 0xc18ae064 drm device (drm device) _at_ _at_/dev/drm/drm_irq.h:192
> 2nd 0xc0872060 ACPI root bus (ACPI root bus) _at_ /usr/src/sys/modules/acpi/acpi/../../../dev/acpica/acpi.c:841
> KDB: stack backtrace:
> kdb_backtrace(c06c0eb4,c0872060,c086c28e,c086c28e,c086c693) at kdb_backtrace+0x2e
> witness_checkorder(c0872060,9,c086c693,349,c06f0bc4) at witness_checkorder+0x6a6
> _sx_xlock(c0872060,c086c693,349,c06f0ba0,40) at _sx_xlock+0x7e
> acpi_release_resource(c1794680,c1742a00,1,0,c18046c0) at acpi_release_resource+0x2b
> bus_generic_release_resource(c1742e00,c1742a00,1,0,c18046c0) at bus_generic_release_resource+0x82
> resource_list_release(c1794084,c1801d00,c1742a00,1,0) at resource_list_release+0x84
> bus_generic_rl_release_resource(c1801d00,c1742a00,1,0,c18046c0) at bus_generic_rl_release_resource+0x86
> bus_generic_release_resource(c1802080,c1742a00,1,0,c18046c0) at bus_generic_release_resource+0x82
> resource_list_release(c1794084,c1742e80,c1742a00,1,0) at resource_list_release+0x13b
> bus_generic_rl_release_resource(c1742e80,c1742a00,1,0,c18046c0) at bus_generic_rl_release_resource+0x86
> bus_release_resource(c1742a00,1,0,c18046c0,c18ae064) at bus_release_resource+0x7f
> radeon_irq_uninstall(c18ae000,0,c1d85640,c0,c1d88130) at radeon_irq_uninstall+0x7b
> radeon_control(c1ce8b00,80086414,d5de0c58,43,c19a22c0) at radeon_control+0x8d
> radeon_ioctl(c1ce8b00,80086414,d5de0c58,43,c19a22c0) at radeon_ioctl+0x1f6
> spec_ioctl(d5de0b80,d5de0c2c,c0590fc1,d5de0b80,1) at spec_ioctl+0x1ce
> spec_vnoperate(d5de0b80,1,c06c6266,30e,c070f8a0) at spec_vnoperate+0x18
> vn_ioctl(c19acd48,80086414,d5de0c58,c1d91480,c19a22c0) at vn_ioctl+0x1c1
> ioctl(c19a22c0,d5de0d14,c,437,3) at ioctl+0x4f2
> syscall(2840002f,bfbf002f,bfbf002f,8945400,8734000) at syscall+0x2a0
> Xint0x80_syscall() at Xint0x80_syscall+0x1f
> --- syscall (54, FreeBSD ELF32, ioctl), eip = 0x2827000f, esp = 0xbfbfeadc, ebp = 0xbfbfeaf8 ---

I can't see how the radeon and acpi locks are interrelated.  Anyone else 
have an idea?  The radeon call is just a simple:

bus_release_resource(dev->device, SYS_RES_IRQ, irqrid, dev->irqr);

Perhaps it's not ok to hold a sx lock while calling into the parent 
(from acpi.c):

ret = BUS_RELEASE_RESOURCE(device_get_parent(bus), child, type, rid, r);

-Nate