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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-01-19 09:26:31 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-28 15:55:56 -0300
commitc32c868ab8b2b95724550d0130782c0767fc3bab (patch)
tree53b43a7f006fe8f549affb6b6d4d24b808a75465 /malloc/Makefile
parentdd45734e322a03287d34d8af9b7da7b35cfddb8e (diff)
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posix: Add _Fork [BZ #4737]
Austin Group issue 62 [1] dropped the async-signal-safe requirement
for fork and provided a async-signal-safe _Fork replacement that
does not run the atfork handlers.  It will be included in the next
POSIX standard.

It allow to close a long standing issue to make fork AS-safe (BZ#4737).
As indicated on the bug, besides the internal lock for the atfork
handlers itself; there is no guarantee that the handlers itself will
not introduce more AS-safe issues.

The idea is synchronize fork with the required internal locks to allow
children in multithread processes to use mostly of standard function
(even though POSIX states only AS-safe function should be used).  On
signal handles, _Fork should be used intead and only AS-safe functions
should be used.

For testing, the new tst-_Fork only check basic usage.  I also added
a new tst-mallocfork3 which uses the same strategy to check for
deadlock of tst-mallocfork2 but using threads instead of subprocesses
(and it does deadlock if it replaces _Fork with fork).

[1] https://austingroupbugs.net/view.php?id=62
Diffstat (limited to 'malloc/Makefile')
-rw-r--r--malloc/Makefile3
1 files changed, 3 insertions, 0 deletions
diff --git a/malloc/Makefile b/malloc/Makefile
index 3162301fba..9bc2e50a9a 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -31,6 +31,7 @@ tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \
 	 tst-malloc-backtrace tst-malloc-thread-exit \
 	 tst-malloc-thread-fail tst-malloc-fork-deadlock \
 	 tst-mallocfork2 \
+	 tst-mallocfork3 \
 	 tst-interpose-nothread \
 	 tst-interpose-thread \
 	 tst-alloc_buffer \
@@ -113,6 +114,8 @@ libmemusage-inhibit-o = $(filter-out .os,$(object-suffixes))
 $(objpfx)tst-malloc-backtrace: $(shared-thread-library)
 $(objpfx)tst-malloc-thread-exit: $(shared-thread-library)
 $(objpfx)tst-malloc-thread-fail: $(shared-thread-library)
+$(objpfx)tst-mallocfork3: $(shared-thread-library)
+$(objpfx)tst-mallocfork3-mcheck: $(shared-thread-library)
 $(objpfx)tst-malloc-fork-deadlock: $(shared-thread-library)
 $(objpfx)tst-malloc-stats-cancellation: $(shared-thread-library)
 $(objpfx)tst-malloc-backtrace-malloc-check: $(shared-thread-library)