KDL "Panic: Invalid concurrent access to page 0x846ed07c"

[humdinger]

This is hrev50931.

Out of the blue, Tracker crashed and after I clicked the "Debug report" button, I toook a trip to KDLand:

Panic: Invalid concurrent access to page 0x846ed07c (start), currently accessed by: 0

Photo attached.

Here's what I found in the previous_syslog, the debug report of the Tracker crash wasn't saved:

870: DEBUGGER: _numBlocks > 0
debug_server: Thread 870 entered the debugger: Debugger call: `_numBlocks > 0'
stack trace, current PC 0x61d19114  commpage_syscall + 0x4:
  (0x7a7f7518)  0x9a8a41  __assert_fail + 0x51
  (0x7a7f7548)  0xa20a7b  isValid__Q28BPrivate10superblock + 0x3b
  (0x7a7f7578)  0xa20d8e  reuse__Q28BPrivate9hoardHeapi + 0x166
  (0x7a7f75b8)  0xa1e8dc  malloc__Q28BPrivate10threadHeapUl + 0x244
  (0x7a7f7608)  0xa1f874  malloc + 0x184
  (0x7a7f7638)  0x995f6d  __builtin_new + 0x29
  (0x7a7f7668)  0x996374  __builtin_vec_new + 0x20
  (0x7a7f7698)  0x1d45b50  ActivityLevel__Fv + 0x50
  (0x7a7f78a8)  0x1d4614a  IsIdle__Q28BPrivate15RunWhenIdleTaskxf + 0x1a
  (0x7a7f78d8)  0x1d46206  IdleTimerExpired__Q28BPrivate15RunWhenIdleTaskx + 0x26
  (0x7a7f7908)  0x1d460b0  RunIfNeeded__Q28BPrivate15RunWhenIdleTaskx + 0xa0
  (0x7a7f7938)  0x1d4696f  Pulse__Q28BPrivate8TaskLoop + 0x7f
  (0x7a7f7978)  0x1d46d8c  Run__Q28BPrivate18StandAloneTaskLoop + 0x88
  (0x7a7f79b8)  0x1d46cfb  RunBinder__Q28BPrivate18StandAloneTaskLoopPv + 0x1f
  (0x7a7f79e8)  0x99f4a3  thread_entry + 0x23
810: DEBUGGER: sb

[humdinger]

KDL photo

[diver]

Possibly a dupe of #13205

[arfonzo]

'Invalid concurrent access to page' occurs here on hrev51149 on Hyper-V.

KDL screenshot: ​https://snag.gy/25cUav.jpg

When this happens the CPUs are pegged at 100% on my hardware, until resetting. Needless to say it's not ideal for hosting build slaves or other headless instances.

[waddlesplash]

Does this still replicate on Hyper-V?

[waddlesplash]

If this is still reproducible, please retest after hrev57989, and upload a new screenshot of the KDL.