panic: deadlres_td_sleep_q: possible deadlock detected on RPI3

[bob prohaska]

My Pi3 running -current r356835 reported:

panic: deadlres_td_sleep_q: possible deadlock detected for 0xfffffd0000eff000, blocked for 1800305 ticks

cpuid = 0
time = 1579775738
KDB: stack backtrace:
db_trace_self() at db_trace_self_wrapper+0x28
	 pc = 0xffff0000007392dc  lr = 0xffff000000106814
	 sp = 0xffff0000520ce580  fp = 0xffff0000520ce790

db_trace_self_wrapper() at vpanic+0x194
	 pc = 0xffff000000106814  lr = 0xffff00000040968c
	 sp = 0xffff0000520ce7a0  fp = 0xffff0000520ce850

vpanic() at panic+0x44
	 pc = 0xffff00000040968c  lr = 0xffff000000409434
	 sp = 0xffff0000520ce860  fp = 0xffff0000520ce8e0

panic() at deadlkres+0x2f8
	 pc = 0xffff000000409434  lr = 0xffff0000003a480c
	 sp = 0xffff0000520ce8f0  fp = 0xffff0000520ce940

deadlkres() at fork_exit+0x7c
	 pc = 0xffff0000003a480c  lr = 0xffff0000003c8a0c
	 sp = 0xffff0000520ce950  fp = 0xffff0000520ce980

fork_exit() at fork_trampoline+0x10
	 pc = 0xffff0000003c8a0c  lr = 0xffff000000755b3c
	 sp = 0xffff0000520ce990  fp = 0x0000000000000000

KDB: enter: panic
[ thread pid 0 tid 100052 ]
Stopped at      0
db> 
db> bt
Tracing pid 0 tid 100052 td 0xfffffd0000ce8560
db_trace_self() at db_stack_trace+0xf8
         pc = 0xffff0000007392dc  lr = 0xffff000000103c58
         sp = 0xffff0000520ce150  fp = 0xffff0000520ce180

db_stack_trace() at db_command+0x228
         pc = 0xffff000000103c58  lr = 0xffff0000001038d0
         sp = 0xffff0000520ce190  fp = 0xffff0000520ce270

db_command() at db_command_loop+0x58
         pc = 0xffff0000001038d0  lr = 0xffff000000103678
         sp = 0xffff0000520ce280  fp = 0xffff0000520ce2a0

db_command_loop() at db_trap+0xf4
         pc = 0xffff000000103678  lr = 0xffff00000010697c
         sp = 0xffff0000520ce2b0  fp = 0xffff0000520ce4d0

db_trap() at kdb_trap+0x1d8
         pc = 0xffff00000010697c  lr = 0xffff000000450af8
         sp = 0xffff0000520ce4e0  fp = 0xffff0000520ce590
        
kdb_trap() at do_el1h_sync+0xf4
         pc = 0xffff000000450af8  lr = 0xffff000000755db8
         sp = 0xffff0000520ce5a0  fp = 0xffff0000520ce5d0

do_el1h_sync() at handle_el1h_sync+0x78
         pc = 0xffff000000755db8  lr = 0xffff00000073b878
         sp = 0xffff0000520ce5e0  fp = 0xffff0000520ce6f0

handle_el1h_sync() at kdb_enter+0x34
         pc = 0xffff00000073b878  lr = 0xffff000000450144
         sp = 0xffff0000520ce700  fp = 0xffff0000520ce790

kdb_enter() at vpanic+0x1b0
         pc = 0xffff000000450144  lr = 0xffff0000004096a8
         sp = 0xffff0000520ce7a0  fp = 0xffff0000520ce850

vpanic() at panic+0x44
         pc = 0xffff0000004096a8  lr = 0xffff000000409434
         sp = 0xffff0000520ce860  fp = 0xffff0000520ce8e0
        
panic() at deadlkres+0x2f8
         pc = 0xffff000000409434  lr = 0xffff0000003a480c
         sp = 0xffff0000520ce8f0  fp = 0xffff0000520ce940

deadlkres() at fork_exit+0x7c
         pc = 0xffff0000003a480c  lr = 0xffff0000003c8a0c
         sp = 0xffff0000520ce950  fp = 0xffff0000520ce980

fork_exit() at fork_trampoline+0x10
         pc = 0xffff0000003c8a0c  lr = 0xffff000000755b3c
         sp = 0xffff0000520ce990  fp = 0x0000000000000000

db> 

For now I'll reboot the old kernel, update sources and start over.

Thanks for reading,

bob prohaska