Yony Yossef wrote:
Hi all.
I'm trying to debug a "spinlock held too long" error.
Therefore I thought compiling my kernel with "options WITNESS" would be a
good idea.
Using the WITNESS kernel I cannot load my driver with any MTX_SPIN mutex.
I had to change it all to MTX_DEF since every MTX_SPIN got me this error:
panic: lock (network driver) spin mutex does not match earlier (sleep mutex)
lock
It means that somewhere you are treating a mutex with that name as a
sleep mutex and in other places as a spin mutex. WITNESS works on the
lock name so this may or may not be a bug.
However, default mutexes should be used in most cases anyway (bear in
mind that default mutexes will also spin when it makes sense for them to
do so).
So I changed it all to MTX_DEF, just to see if things will work.
Now I can load my driver, but calling ifconfig shows a new crash:
mtnic0: Activating port:1
mtnic0: Ethernet address: 00:00:00:00:08:88
mtnic0: Activating port:2
mtnic1: Ethernet address: 00:00:00:00:08:89
lock order reversal: (sleepable after non-sleepable)
1st 0xffffffff81379010 MTNIC state semaphore (MTNIC state semaphore) @
mtnic_netdev.c:1855
2nd 0xffffffff809eee00 ACPI root bus (ACPI root bus) @
/usr/src/sys/dev/acpica/acpi.c:1022
You are acquiring a lock that is "sleepable" (i.e. legal for consumers
to sleep while holding it), after first acquiring another lock that is
not sleepable. The danger is that if some code sleeps while holding
both the first and second lock, then other code that tries to acquire
the first lock will deadlock indefinitely.
This is often due to a programming or design error.
Kris
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
witness_checkorder() at witness_checkorder+0x559
_sx_xlock() at _sx_xlock+0x32
acpi_alloc_resource() at acpi_alloc_resource+0x9a
pci_alloc_resource() at pci_alloc_resource+0x81
resource_list_alloc() at resource_list_alloc+0x17a
pci_alloc_resource() at pci_alloc_resource+0x81
bus_alloc_resource() at bus_alloc_resource+0x89
mtnic_start_port() at mtnic_start_port+0x4f1
mtnic_open() at mtnic_open+0xb2
ether_ioctl() at ether_ioctl+0xb5
mtnic_ioctl() at mtnic_ioctl+0x3e
in_ifinit() at in_ifinit+0x8d
in_control() at in_control+0xc66
ifioctl() at ifioctl+0xea
kern_ioctl() at kern_ioctl+0xa3
ioctl() at ioctl+0xf9
syscall() at syscall+0x1b5
Xfast_syscall() at Xfast_syscall+0xab
--- syscall (54, FreeBSD ELF64, ioctl), rip = 0x800824cfc, rsp =
0x7fffffffe3b8, rbp = 0x7fffffffee10 ---
KDB: enter: witness_checkorder
[thread pid 1051 tid 100069 ]
Stopped at kdb_enter+0x31: leave
db>
Can anybody please tell me what is going on here?
-Yony
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