uk_init_tls: Initialize the TSD to the value expected by musl #82
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Even if the TSD has been initialized already, the first call to `pthread_create` will (re)set it to point to the statically-allocated `__pthread_tsd_main` (see (1)). So, before this patch, the memory allocated for the TSD leaked and, worse, the following sequence: ``` pthread_key_create(&key, NULL); pthread_setspecific(key, value); assert(pthread_getspecific(key) == value); pthread_create(&th, NULL, &thrd, NULL); assert(pthread_getspecific(key) == value); ``` ended up with the final assertion failing. (1) src/thread/pthread_create.c line 255 in musl v1.2.3 Signed-off-by: Samuel Hym <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Even if the TSD has been initialized already, the first call to
pthread_createwill (re)set it to point to the statically-allocated__pthread_tsd_main(see (1)). So, before this patch, the memory allocated for the TSD leaked and, worse, the following sequence:ended up with the final assertion failing.
I’ve tested this example without and with the modification in CI:
(1) src/thread/pthread_create.c line 255 in musl v1.2.3
This was discovered investigating a segfault in the OCaml runtime, where some information is stored in the TSD in all cases, even for the initial thread. Accessing that information after a new thread has been created triggered the segfault.