Bug 243876 - panic: deadlres_td_sleep_q: possible deadlock detected for 0xfffffd0000eff000, blocked for 1800305 ticks
Summary: panic: deadlres_td_sleep_q: possible deadlock detected for 0xfffffd0000eff000...
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: arm (show other bugs)
Version: CURRENT
Hardware: arm64 Any
: --- Affects Only Me
Assignee: freebsd-arm mailing list
URL:
Keywords: panic
Depends on:
Blocks:
 
Reported: 2020-02-04 16:49 UTC by Bob Prohaska
Modified: 2020-06-03 17:00 UTC (History)
3 users (show)

See Also:


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Description Bob Prohaska 2020-02-04 16:49:08 UTC
Apologies if this is duplicate, first observation was on January 23, 2020

A Pi3 running -current (initially at r356835) persistently crashes during
buildworld, reporting:
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>

The panic can also be triggered after a prompt hang by invoking 

kldload mac_ntpd

The machine freezes initially, but panics after a delay of some minutes.
Comment 1 Mark Johnston freebsd_committer 2020-06-03 17:00:03 UTC
I think there were some mailing list threads about this?  Was it ever resolved, or is it still reproducible?  If it still occurs, please show output from

db> show thread <addr>
Thread XXXXXX at <addr>
...
db> thread XXXXXX
db> bt

where <addr> is the address from the panic message.