PANIC: entries count was not decremented for a long time!

[jmairboeck]

It seems that a form of #17455 can still occur very rarely. This is the same system, running in VirtualBox, using 2 virtual CPU cores.

KERN: PANIC: entries count was not decremented for a long time!
KERN: Welcome to Kernel Debugging Land...
KERN: Thread 412 "Startup control" running on CPU 0
KERN: stack trace for thread 412 "Startup control"
KERN:     kernel stack: 0xffffffff80745000 to 0xffffffff8074a000
KERN:       user stack: 0x00007f21466ec000 to 0x00007f214672c000
KERN: frame                       caller             <image>:function + offset
KERN:  0 ffffffff80749b38 (+  24) ffffffff8014435c   <kernel_x86_64> arch_debug_call_with_fault_handler + 0x16
KERN:  1 ffffffff80749b50 (+  80) ffffffff800ae268   <kernel_x86_64> debug_call_with_fault_handler + 0x78
KERN:  2 ffffffff80749ba0 (+  96) ffffffff800af883   <kernel_x86_64> kernel_debugger_loop(char const*, char const*, __va_list_tag*, int) + 0xf3
KERN:  3 ffffffff80749c00 (+  80) ffffffff800afc1e   <kernel_x86_64> kernel_debugger_internal(char const*, char const*, __va_list_tag*, int) + 0x6e
KERN:  4 ffffffff80749c50 (+ 240) ffffffff800aff77   <kernel_x86_64> panic + 0xb7
KERN:  5 ffffffff80749d40 (+  96) ffffffff80056f95   <kernel_x86_64> ConditionVariable::_NotifyLocked(bool, int) + 0x155
KERN:  6 ffffffff80749da0 (+  64) ffffffff800573d4   <kernel_x86_64> ConditionVariable::_Notify(bool, int) + 0x44
KERN:  7 ffffffff80749de0 (+ 208) ffffffff8006e78d   <kernel_x86_64> writev_port_etc + 0x57d
KERN:  8 ffffffff80749eb0 (+ 112) ffffffff8006f086   <kernel_x86_64> _user_write_port_etc + 0x96
KERN:  9 ffffffff80749f20 (+  16) ffffffff80145e4f   <kernel_x86_64> x86_64_syscall_entry + 0xfb
KERN: user iframe at 0xffffffff80749f30 (end = 0xffffffff80749ff8)
KERN:  rax 0xdf                  rbx 0xe9                  rcx 0x1719bc687cc
KERN:  rdx 0x7f214672b820        rsi 0x306                 rdi 0xe9
KERN:  rbp 0x7f214672b810         r8 0x8                    r9 0xe4e1c0
KERN:  r10 0xd0                  r11 0x202                 r12 0x110dabebe0a0
KERN:  r13 0x306                 r14 0x7f214672b820        r15 0xd0
KERN:  rip 0x1719bc687cc         rsp 0x7f214672b7d8     rflags 0x202
KERN:  vector: 0x63, error code: 0x0
KERN: 10 ffffffff80749f30 (+139783032412384) 000001719bc687cc   <libroot.so> _kern_write_port_etc + 0x0c
KERN: 11 00007f214672b810 (+ 256) 0000007a7b956b33   <libmedia.so> BBufferProducer::SendBuffer(BBuffer*, media_source const&, media_destination const&) + 0x153
KERN: 12 00007f214672b910 (+ 192) 0000007a7b987b8d   <libmedia.so> BPrivate::SoundPlayNode::SendNewBuffer(media_timed_event const*, long, bool) + 0x11d
KERN: 13 00007f214672b9d0 (+  32) 0000007a7b95d497   <libmedia.so> BMediaEventLooper::DispatchEvent(media_timed_event const*, long, bool) + 0x17
KERN: 14 00007f214672b9f0 (+ 224) 0000007a7b95d739   <libmedia.so> BMediaEventLooper::ControlLoop() + 0x209
KERN: 15 00007f214672bad0 (+  32) 0000007a7b95d2a1   <libmedia.so> BMediaEventLooper::_ControlThreadStart(void*) + 0x21
KERN: 16 00007f214672baf0 (+  32) 000001719bc67599   <libroot.so> _thread_do_exit_work (nearest) + 0x89
KERN: 17 00007f214672bb10 (+   0) 00007fcfae30f260   <commpage> commpage_thread_exit + 0x00
KERN: kdebug> coKERN: variable pointer was not unset for a long time!

This just occurred once so far after a few hours of uptime, while doing some work (so it was not just idling). The KDL is continuable.

hrev55993

[waddlesplash]

Downgraded in hrev56074.