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authorKonstantin Belousov <kib@FreeBSD.org>2021-01-12 09:02:37 +0000
committerKonstantin Belousov <kib@FreeBSD.org>2021-01-12 10:45:44 +0000
commit85d028223bc2768651f4d44881644ceb5dc2a664 (patch)
tree72b748fcf5e4d4e6cefc897c0bf4750c48e69b91
parent57f22c828ec01e0d92bc8858f61df06b4d81ea5c (diff)
downloadsrc-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.c13
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);
}