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| author | Rich Felker <dalias@aerifal.cx> | 2019-02-16 09:13:45 -0500 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2019-02-16 10:11:22 -0500 |
| commit | e4235d70672d9751d7718ddc2b52d0b426430768 (patch) | |
| tree | cf4d965f2a440b641adca6fd3ddf5f17278e3210 /src/thread/pthread_create.c | |
| parent | 8f11e6127fe93093f81a52b15bb1537edc3fc8af (diff) | |
| download | musl-e4235d70672d9751d7718ddc2b52d0b426430768.tar.gz | |
rewrite __synccall in terms of global thread list
the __synccall mechanism provides stop-the-world synchronous execution
of a callback in all threads of the process. it is used to implement
multi-threaded setuid/setgid operations, since Linux lacks them at the
kernel level, and for some other less-critical purposes.
this change eliminates dependency on /proc/self/task to determine the
set of live threads, which in addition to being an unwanted dependency
and a potential point of resource-exhaustion failure, turned out to be
inaccurate. test cases provided by Alexey Izbyshev showed that it
could fail to reflect newly created threads. due to how the
presignaling phase worked, this usually yielded a deadlock if hit, but
in the worst case it could also result in threads being silently
missed (allowed to continue running without executing the callback).
Diffstat (limited to 'src/thread/pthread_create.c')
| -rw-r--r-- | src/thread/pthread_create.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index 03cdea0a..cec82157 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -201,8 +201,6 @@ weak_alias(dummy, __pthread_tsd_size); static void *dummy_tsd[1] = { 0 }; weak_alias(dummy_tsd, __pthread_tsd_main); -volatile int __block_new_threads = 0; - static FILE *volatile dummy_file = 0; weak_alias(dummy_file, __stdin_used); weak_alias(dummy_file, __stdout_used); @@ -247,8 +245,6 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att attr._a_guardsize = __default_guardsize; } - if (__block_new_threads) __wait(&__block_new_threads, 0, 1, 1); - if (attr._a_stackaddr) { size_t need = libc.tls_size + __pthread_tsd_size; size = attr._a_stacksize; |