scissors plugin exits with "ERROR: replay failed"

[ghost]

Using the April PANDA VM published in the PANDA blog (pandavm-20150413.tar.bz2) I have made a recording of an android target approx. 2.3 billion instructions long (the recording files are ~450 MB snapshot and a ~5 MB log).

The issue scenario is as follows:

1. I verify that the captured replay is correct by running it again and again and watching it complete without errors.
2. Using the "stringsearch" plugin on the replay, I identify an interesting region in the recording that is approx. its last 10% (from ~2.1 G instructions to ~2.28 G instructions)
3. I copy the start and end GIC values from the stringsearch output, and then run the replay with various start and end values.
   • if start ~2.1G and end ~2.28 G (the range I really need) I always get "ERROR: replay failed" at the precise moment the execution reaches the GIC specified in the 'start' parameter.
   • Then I try to narrow down the problematic GIC range.
     • if start == 1000000 and end == 2000000, the scissors work
     • if start == 10000000 and end == 20000000, it crashes with a segfault
     • if start == 100000000 and end == 200000000, it reports "ERROR: replay failed" when the GIC = 99999998
     • if start == 0 and end ~2.1G, the scissors work
     • if start == 0 and end ~2.2G, the scissors work
     • if start == 100000000 and end ~2.2G, the scissors work
     • if start ~1G and end ~2.2G, it reports "ERROR: replay failed" when the GIC is slightly less than 1G

Please advise on how to debug and resolve such an issue.

[moyix]

Would it be possible to pack up the log file (using rrpack) and post it somewhere along with the command line used for the replay so we can reproduce & fix?

For example, perhaps you could upload it to www.rrshare.org?

[ghost]

Hi, thank you for the response, unfortunately it is not possible to get any data at all from the target environment.
I will try to reproduce the issue on a newer October VM and report here.

[ghost]

Captured the whole run on an October 2015 VM, the scissors worked.
Thank you, now closing the issue.