diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | stdlib/tst-setcontext9.c | 47 |
2 files changed, 44 insertions, 9 deletions
diff --git a/ChangeLog b/ChangeLog index e15ac3bdb1..d5becac41c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2018-09-19 Carlos O'Donell <carlos@redhat.com> + + * stdlib/tst-setcontext9.c (f1): Rename to... + (f1a): ... this. + (f1b): New function implementing lower half of f1 in alternate stack. + 2018-09-19 Paul Eggert <eggert@cs.ucla.edu> Fix mktime localtime offset confusion diff --git a/stdlib/tst-setcontext9.c b/stdlib/tst-setcontext9.c index 4636ce9030..db8355766c 100644 --- a/stdlib/tst-setcontext9.c +++ b/stdlib/tst-setcontext9.c @@ -41,26 +41,55 @@ f2 (void) } static void -f1 (void) +f1b (void) { - puts ("start f1"); - if (getcontext (&ctx[2]) != 0) - { - printf ("%s: getcontext: %m\n", __FUNCTION__); - exit (EXIT_FAILURE); - } if (done) { - puts ("set context in f1"); + puts ("set context in f1b"); if (setcontext (&ctx[3]) != 0) { printf ("%s: setcontext: %m\n", __FUNCTION__); exit (EXIT_FAILURE); } } + exit (EXIT_FAILURE); +} + +static void +f1a (void) +{ + char st2[32768]; + puts ("start f1a"); + if (getcontext (&ctx[2]) != 0) + { + printf ("%s: getcontext: %m\n", __FUNCTION__); + exit (EXIT_FAILURE); + } + ctx[2].uc_stack.ss_sp = st2; + ctx[2].uc_stack.ss_size = sizeof st2; + ctx[2].uc_link = &ctx[0]; + makecontext (&ctx[2], (void (*) (void)) f1b, 0); f2 (); } +/* The execution path through the test looks like this: + do_test (call) + -> "making contexts" + -> "swap contexts" + f1a (via swapcontext to ctx[1], with alternate stack) + -> "start f1a" + f2 (call) + -> "swap contexts in f2" + f1b (via swapcontext to ctx[2], with alternate stack) + -> "set context in f1b" + do_test (via setcontext to ctx[3], main stack) + -> "setcontext" + f2 (via setcontext to ctx[4], with alternate stack) + -> "end f2" + + We must use an alternate stack for f1b, because if we don't then the + result of executing an earlier caller may overwrite registers + spilled to the stack in f2. */ static int do_test (void) { @@ -79,7 +108,7 @@ do_test (void) ctx[1].uc_stack.ss_sp = st1; ctx[1].uc_stack.ss_size = sizeof st1; ctx[1].uc_link = &ctx[0]; - makecontext (&ctx[1], (void (*) (void)) f1, 0); + makecontext (&ctx[1], (void (*) (void)) f1a, 0); puts ("swap contexts"); if (swapcontext (&ctx[3], &ctx[1]) != 0) { |