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[PPC64] Fix trapstk overflow

Authored by luporl on Wed, Oct 30, 9:27 PM.



In some scenarios, the 4K trapstk may overflow, corrupting tmpstk.

This was observed during remote debugging, with the following steps:

At remote host (R):

  • enter kdb during boot
  • switch to gdb backend

At local host (L):

  • attach gdb to R
  • try to read an invalid memory position

At R:

  • a DSI trap occurs and kdb restarts (all this occurs on trapstk)
  • while printing the stacktrace, trapstk overflows and corrupts tmpstk

Diff Detail

rS FreeBSD src repository
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Automatic diff as part of commit; unit tests not applicable.

Event Timeline

luporl created this revision.Wed, Oct 30, 9:27 PM
jhibbits accepted this revision.Wed, Oct 30, 9:35 PM
This revision is now accepted and ready to land.Wed, Oct 30, 9:35 PM
This revision was automatically updated to reflect the committed changes.