Re: lock order reversal in sys/kern/vfs_mount.c

On Friday, June 08, 2012 4:21:34 am Ruslan Mahmatkhanov wrote:
> Ruslan Mahmatkhanov wrote on 08.06.2012 12:10:
> > Good day,
> >
> > After updating to yesterdays -current, I got this on boot:
> >
> > lock order reversal:
> > 1st 0xfffffe0007b04c38 ufs (ufs) _at_ /usr/src/sys/kern/vfs_mount.c:1254
> > 2nd 0xfffffe0007ed9478 devfs (devfs) _at_ /usr/src/sys/kern/vfs_subr.c:2158
> > KDB: stack backtrace:
> > db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
> > kdb_backtrace() at kdb_backtrace+0x37
> > _witness_debugger() at _witness_debugger+0x2c
> > witness_checkorder() at witness_checkorder+0x853
> > __lockmgr_args() at __lockmgr_args+0x113a
> > vop_stdlock() at vop_stdlock+0x39
> > VOP_LOCK1_APV() at VOP_LOCK1_APV+0xbf
> > _vn_lock() at _vn_lock+0x47
> > vget() at vget+0x7b
> > devfs_allocv() at devfs_allocv+0x13f
> > devfs_root() at devfs_root+0x4d
> > dounmount() at dounmount+0x45c
> > vfs_unmountall() at vfs_unmountall+0x4c
> > kern_reboot() at kern_reboot+0x84b
> > sys_reboot() at sys_reboot+0x68
> > amd64_syscall() at amd64_syscall+0x2e0
> > Xfast_syscall() at Xfast_syscall+0xf7
> > --- syscall (55, FreeBSD ELF64, sys_reboot), rip = 0x40ebbc, rsp =
> > 0x7fffffffd6c8, rbp = 0x65 ---
> >
> > Reverting to old kernel (that was built about a week ago) helped to
> > avoid this. Any thoughts?
> 
> And this one comes up with the recent update too:
> 
> driver bug: Unable to set devclass (class: acpi_sysresource devname: 
> (unknown))
> driver bug: Unable to set devclass (class: acpi_timer devname: (unknown))
> cpu0: <ACPI CPU> on acpi0
> driver bug: Unable to set devclass (class: acpi_sysresource devname: 
> (unknown))
> cpu1: <ACPI CPU> on acpi0
> driver bug: Unable to set devclass (class: acpi_sysresource devname: 
> (unknown))
> cpu2: <ACPI CPU> on acpi0
> driver bug: Unable to set devclass (class: acpi_sysresource devname: 
> (unknown))
> cpu3: <ACPI CPU> on acpi0
> 
> What the additional info should I supply to understand what's wrong?
> Here is my full dmesg; http://people.freebsd.org/~rm/dmesg.txt

Is this a verbose boot?  Also, can you try this to get more details in
the log message:

Index: subr_bus.c
===================================================================
--- subr_bus.c	(revision 236680)
+++ subr_bus.c	(working copy)
_at__at_ -1988,7 +1990,7 _at__at_ device_probe_child(device_t dev, device_t child)
 	devclass_t dc;
 	driverlink_t best = NULL;
 	driverlink_t dl;
-	int result, pri = 0;
+	int error, result, pri = 0;
 	int hasclass = (child->devclass != NULL);
 
 	GIANT_REQUIRED;
_at__at_ -2019,17 +2021,18 _at__at_ device_probe_child(device_t dev, device_t child)
 			else if (result != 0)
 				continue;
 			if (!hasclass) {
-				if (device_set_devclass(child,
-				    dl->driver->name) != 0) {
+				error = device_set_devclass(child,
+				    dl->driver->name);
+				if (error != 0) {
 					char const * devname =
 					    device_get_name(child);
 					if (devname == NULL)
 						devname = "(unknown)";
 					printf("driver bug: Unable to set "
 					    "devclass (class: %s "
-					    "devname: %s)\n",
+					    "devname: %s): %d\n",
 					    dl->driver->name,
-					    devname);
+					    devname, error);
 					(void)device_set_driver(child, NULL);
 					continue;
 				}


-- 
John Baldwin