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| author | Konstantin Belousov <kib@FreeBSD.org> | 2021-01-12 09:02:37 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2021-01-12 10:45:44 +0000 |
| commit | 85d028223bc2768651f4d44881644ceb5dc2a664 (patch) | |
| tree | 72b748fcf5e4d4e6cefc897c0bf4750c48e69b91 | |
| parent | 57f22c828ec01e0d92bc8858f61df06b4d81ea5c (diff) | |
| download | src-85d028223bc2768651f4d44881644ceb5dc2a664.tar.gz src-85d028223bc2768651f4d44881644ceb5dc2a664.zip | |
libthr malloc: support recursion on thr_malloc_umtx.
One possible way the recursion can happen is during fork: suppose
that fork is called from early code that did not triggered
jemalloc(3) initialization yet. Then we lock thr_malloc lock, and
call malloc_prefork() that might require initialization of jemalloc
pthread_mutexes, calling into libthr malloc. It is safe to allow
recursion for this occurence.
PR: 252579
Reported by: Vasily Postnicov <shamaz.mazum@gmail.com>
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
| -rw-r--r-- | lib/libthr/thread/thr_malloc.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/lib/libthr/thread/thr_malloc.c b/lib/libthr/thread/thr_malloc.c index 2f1c81142942..80a81f9c6c27 100644 --- a/lib/libthr/thread/thr_malloc.c +++ b/lib/libthr/thread/thr_malloc.c @@ -41,6 +41,7 @@ int npagesizes; size_t *pagesizes; static size_t pagesizes_d[2]; static struct umutex thr_malloc_umtx; +static u_int thr_malloc_umtx_level; void __thr_malloc_init(void) @@ -60,11 +61,16 @@ __thr_malloc_init(void) static void thr_malloc_lock(struct pthread *curthread) { + uint32_t curtid; if (curthread == NULL) return; curthread->locklevel++; - _thr_umutex_lock(&thr_malloc_umtx, TID(curthread)); + curtid = TID(curthread); + if ((uint32_t)thr_malloc_umtx.m_owner == curtid) + thr_malloc_umtx_level++; + else + _thr_umutex_lock(&thr_malloc_umtx, curtid); } static void @@ -73,7 +79,10 @@ thr_malloc_unlock(struct pthread *curthread) if (curthread == NULL) return; - _thr_umutex_unlock(&thr_malloc_umtx, TID(curthread)); + if (thr_malloc_umtx_level > 0) + thr_malloc_umtx_level--; + else + _thr_umutex_unlock(&thr_malloc_umtx, TID(curthread)); curthread->locklevel--; _thr_ast(curthread); } |