diff options
Diffstat (limited to 'nptl-Add-one-more-barrier-to-nptl-tst-create1.patch')
| -rw-r--r-- | nptl-Add-one-more-barrier-to-nptl-tst-create1.patch | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/nptl-Add-one-more-barrier-to-nptl-tst-create1.patch b/nptl-Add-one-more-barrier-to-nptl-tst-create1.patch new file mode 100644 index 0000000..e18a8bc --- /dev/null +++ b/nptl-Add-one-more-barrier-to-nptl-tst-create1.patch @@ -0,0 +1,67 @@ +From 5cc338565479a620244c2f8ff35956629c4dbf81 Mon Sep 17 00:00:00 2001 +From: Florian Weimer <fweimer@redhat.com> +Date: Fri, 10 Dec 2021 05:14:24 +0100 +Subject: [PATCH] nptl: Add one more barrier to nptl/tst-create1 + +Without the bar_ctor_finish barrier, it was possible that thread2 +re-locked user_lock before ctor had a chance to lock it. ctor then +blocked in its locking operation, xdlopen from the main thread +did not return, and thread2 was stuck waiting in bar_dtor: + +thread 1: started. +thread 2: started. +thread 2: locked user_lock. +constructor started: 0. +thread 1: in ctor: started. +thread 3: started. +thread 3: done. +thread 2: unlocked user_lock. +thread 2: locked user_lock. + +Fixes the test in commit 83b5323261bb72313bffcf37476c1b8f0847c736 +("elf: Avoid deadlock between pthread_create and ctors [BZ #28357]"). + +Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> +--- + sysdeps/pthread/tst-create1.c | 4 ++++ + 1 file changed, 4 insertions(+) + +diff --git a/sysdeps/pthread/tst-create1.c b/sysdeps/pthread/tst-create1.c +index 932586c..763ded8 100644 +--- a/sysdeps/pthread/tst-create1.c ++++ b/sysdeps/pthread/tst-create1.c +@@ -33,6 +33,7 @@ thread 2: lock(user_lock) -> pthread_create + */ + + static pthread_barrier_t bar_ctor; ++static pthread_barrier_t bar_ctor_finish; + static pthread_barrier_t bar_dtor; + static pthread_mutex_t user_lock = PTHREAD_MUTEX_INITIALIZER; + +@@ -46,6 +47,7 @@ ctor (void) + xpthread_mutex_unlock (&user_lock); + dprintf (1, "thread 1: in ctor: unlocked user_lock.\n"); + dprintf (1, "thread 1: in ctor: done.\n"); ++ xpthread_barrier_wait (&bar_ctor_finish); + } + + void +@@ -81,6 +83,7 @@ thread2 (void *a) + xpthread_mutex_unlock (&user_lock); + dprintf (1, "thread 2: unlocked user_lock.\n"); + xpthread_join (t3); ++ xpthread_barrier_wait (&bar_ctor_finish); + + xpthread_mutex_lock (&user_lock); + dprintf (1, "thread 2: locked user_lock.\n"); +@@ -99,6 +102,7 @@ thread1 (void) + { + dprintf (1, "thread 1: started.\n"); + xpthread_barrier_init (&bar_ctor, NULL, 2); ++ xpthread_barrier_init (&bar_ctor_finish, NULL, 2); + xpthread_barrier_init (&bar_dtor, NULL, 2); + pthread_t t2 = xpthread_create (0, thread2, 0); + void *p = xdlopen ("tst-create1mod.so", RTLD_NOW | RTLD_GLOBAL); +-- +1.8.3.1 + |