Commit 7a1ff354 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

selftests: net: py: ensure defer() is only used within a test case 



I wasted a couple of hours recently after accidentally adding
a defer() from within a function which itself was called as
part of defer(). This leads to an infinite loop of defer().
Make sure this cannot happen and raise a helpful exception.

I understand that the pair of _ksft_defer_arm() calls may
not be the most Pythonic way to implement this, but it's
easy enough to understand.

Reviewed-by: default avatarPetr Machata <petrm@nvidia.com>
Link: https://patch.msgid.link/20260108225257.2684238-2-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 799a4912

tools/testing/selftests/net/lib/py/ksft.py

+7 −0
Original line number Diff line number Diff line
@@ -153,6 +153,11 @@ def ktap_result(ok, cnt=1, case_name="", comment=""): 
    print(res, flush=True)





def _ksft_defer_arm(state):

    """ Allow or disallow the use of defer() """

    utils.GLOBAL_DEFER_ARMED = state





def ksft_flush_defer():

    global KSFT_RESULT
@@ -315,6 +320,7 @@ def ksft_run(cases=None, globs=None, case_pfx=None, args=()): 
        comment = ""

        cnt_key = ""



        _ksft_defer_arm(True)

        try:

            func(*args)

        except KsftSkipEx as e:
@@ -332,6 +338,7 @@ def ksft_run(cases=None, globs=None, case_pfx=None, args=()): 
                ksft_pr(f"Stopping tests due to {type(e).__name__}.")

            KSFT_RESULT = False

            cnt_key = 'fail'

        _ksft_defer_arm(False)



        try:

            ksft_flush_defer()

tools/testing/selftests/net/lib/py/utils.py

+3 −0
Original line number Diff line number Diff line
@@ -142,6 +142,7 @@ class bkg(cmd): 




GLOBAL_DEFER_QUEUE = []

GLOBAL_DEFER_ARMED = False





class defer:
@@ -153,6 +154,8 @@ class defer: 
        self.args = args

        self.kwargs = kwargs



        if not GLOBAL_DEFER_ARMED:

            raise Exception("defer queue not armed, did you use defer() outside of a test case?")

        self._queue = GLOBAL_DEFER_QUEUE

        self._queue.append(self)