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Cygwin: fork: reserve dynloaded dll areas earlier

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In dll_crt0_0, both threadinterface->Init and sigproc_init allocate
windows object handles using unpredictable memory regions, which may
collide with dynamically loaded dlls when they were relocated.
This commit is contained in:
Michael Haubenwallner 2019-03-26 17:38:36 +01:00 committed by Corinna Vinschen
parent e0fd15c91b
commit 023c107a22
2 changed files with 6 additions and 6 deletions
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6
winsup/cygwin/dcrt0.cc
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@ -632,6 +632,12 @@ child_info_fork::handle_fork ()
if (fixup_mmaps_after_fork (parent)) if (fixup_mmaps_after_fork (parent))
api_fatal ("recreate_mmaps_after_fork_failed"); api_fatal ("recreate_mmaps_after_fork_failed");
/* We need to occupy the address space for dynamically loaded dlls
before we allocate any dynamic object, or we may end up with
error "address space needed by <dll> is already occupied"
for no good reason (seen with some relocated dll). */
dlls.reserve_space ();
} }
bool bool

6
winsup/cygwin/fork.cc
View File

@ -136,12 +136,6 @@ frok::child (volatile char * volatile here)
{ {
HANDLE& hParent = ch.parent; HANDLE& hParent = ch.parent;
/* NOTE: Logically this belongs in dll_list::load_after_fork, but by
doing it here, before the first sync_with_parent, we can exploit
the existing retry mechanism in hopes of getting a more favorable
address space layout next time. */
dlls.reserve_space ();
sync_with_parent ("after longjmp", true); sync_with_parent ("after longjmp", true);
debug_printf ("child is running. pid %d, ppid %d, stack here %p", debug_printf ("child is running. pid %d, ppid %d, stack here %p",
myself->pid, myself->ppid, __builtin_frame_address (0)); myself->pid, myself->ppid, __builtin_frame_address (0));