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| author | Jeremy Drake <cygwin@jdrake.com> | 2025-09-19 13:36:30 -0700 |
|---|---|---|
| committer | Jeremy Drake <cygwin@jdrake.com> | 2025-09-20 11:35:32 -0700 |
| commit | 8a5d39527f9a56d1a623e86d30af6b590fd1472d (patch) | |
| tree | 7d5c42fc319a553f65c19f00a8091b63f3221332 | |
| parent | 3a03874f73db015d93c3b54c6bad32a2852c591e (diff) | |
| download | newlib-8a5d39527f9a56d1a623e86d30af6b590fd1472d.zip newlib-8a5d39527f9a56d1a623e86d30af6b590fd1472d.tar.gz newlib-8a5d39527f9a56d1a623e86d30af6b590fd1472d.tar.bz2 | |
Cygwin: lock cygheap during fork
another thread may simultaneously be doing a cmalloc/cfree while the
cygheap is being copied to the child.
Addresses: https://cygwin.com/pipermail/cygwin/2025-September/258801.html
Signed-off-by: Jeremy Drake <cygwin@jdrake.com>
| -rw-r--r-- | winsup/cygwin/fork.cc | 7 | ||||
| -rw-r--r-- | winsup/cygwin/release/3.6.5 | 4 |
2 files changed, 10 insertions, 1 deletions
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc index 4abc525..7156fc3 100644 --- a/winsup/cygwin/fork.cc +++ b/winsup/cygwin/fork.cc @@ -329,6 +329,7 @@ frok::parent (volatile char * volatile stack_here) /* NEVER, EVER, call a function which in turn calls malloc&friends while this malloc lock is active! */ __malloc_lock (); + cygheap->lock (); bool locked = true; /* Remove impersonation */ @@ -483,6 +484,7 @@ frok::parent (volatile char * volatile stack_here) impure, impure_beg, impure_end, NULL); + cygheap->unlock (); __malloc_unlock (); locked = false; if (!rc) @@ -568,7 +570,10 @@ cleanup: if (fix_impersonation) cygheap->user.reimpersonate (); if (locked) - __malloc_unlock (); + { + cygheap->unlock (); + __malloc_unlock (); + } /* Remember to de-allocate the fd table. */ if (hchild) diff --git a/winsup/cygwin/release/3.6.5 b/winsup/cygwin/release/3.6.5 index 6a37b6a..d7cf838 100644 --- a/winsup/cygwin/release/3.6.5 +++ b/winsup/cygwin/release/3.6.5 @@ -25,3 +25,7 @@ Fixes: - Fix Ctrl-O (FLUSHO) handling. Addresses: https://cygwin.com/pipermail/cygwin/2025-August/258717.html + +- Fix multi-thread safety of fork()/exec() by adding the same locking as was + done for spawn. + Addresses: https://cygwin.com/pipermail/cygwin/2025-September/258801.html |