[glibc] malloc: Initiate tcache shutdown even without allocations [BZ #28028]

[glibc] malloc: Initiate tcache shutdown even without allocations [BZ #28028]

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=dfec225ee1972488bb48a8b67a2c4a13010c334a

commit dfec225ee1972488bb48a8b67a2c4a13010c334a
Author: JeffyChen <jeffy.chen@rock-chips.com>
Date:   Fri Jul 2 17:39:24 2021 +0200

    malloc: Initiate tcache shutdown even without allocations [BZ #28028]
    
    After commit 1e26d35193efbb29239c710a4c46a64708643320 ("malloc: Fix
    tcache leak after thread destruction [BZ #22111]"),
    tcache_shutting_down is still not early enough.  When we detach a
    thread with no tcache allocated, tcache_shutting_down would still be
    false.
    
    Reviewed-by: DJ Delorie <dj@redhat.com>

Diff:
---
 malloc/malloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index 0e2e1747e0..bb9a1642aa 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3144,12 +3144,13 @@ tcache_thread_shutdown (void)
   int i;
   tcache_perthread_struct *tcache_tmp = tcache;
 
+  tcache_shutting_down = true;
+
   if (!tcache)
     return;
 
   /* Disable the tcache and prevent it from being reinitialized.  */
   tcache = NULL;
-  tcache_shutting_down = true;
 
   /* Free all of the entries and the tcache itself back to the arena
      heap for coalescing.  */