#12703: Anomalous/incorrect behavior of get_team_info() in conjunction with
start_watching_system()
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Reporter: anevilyak | Owner: bonefish
Type: bug | Status: new
Priority: normal | Milestone: Unscheduled
Component: System/Kernel | Version: R1/Development
Keywords: | Blocked By:
Blocking: | Has a Patch: 0
Platform: All |
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In order to monitor teams being created/destroyed as part of some
Debugger-related refactoring, I set up some code that uses the private
start/stop_watching_system() APIs to be notified of those events, as
be_roster only covers BApplications, and cannot be relied upon in the CLI
case anyways.
However, something appears to be not entirely correct here, as there seems
to be a relatively reliably reproducible case where the notifications
arrives that a new team was created, and then turning around to retrieve
the corresponding team's info succeeds, but the team_info struct in
question only has the team_id itself filled in. The args are empty, image
and thread count are 0 (though argc is surprisingly 1), and as such it's
impossible to determine from said info what the launched app actually was.
Waiting for a bit and requesting the info succeeds though, so it seems
there's some race here on the kernel side. Attached a testcase that can
relatively easily reproduce the problem. It can be compiled from the root
of the Haiku tree using:
{{{ g++ -g testcase.cpp -Iheaders/private/system -Iheaders/private/kernel
-o testcase -lroot }}}
Running the program and then simply creating new Terminals repeatedly
using the cmd+n Terminal shortcut will relatively reliably trigger it
within 3-4 new Terminals here, and the code in question is set up to
trigger a debugger call when the issue is detected. Interestingly, the
actual team that exhibits the problem is quite reliably the one belonging
to the newly created Terminal app itself, none of the bash, etc.
subprocesses appear to wind up being affected.
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Ticket URL: <https://dev.haiku-os.org/ticket/12703>
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