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1ad049b7b6
the problem: there is a (single-instruction) race condition window between a thread flagging itself dead and decrementing itself from the thread count. if it receives the rsyscall signal at this exact moment, the rsyscall caller will never succeed in signalling enough flags to succeed, and will deadlock forever. in previous versions of musl, the about-to-terminate thread masked all signals prior to decrementing the thread count, but this cost a whole syscall just to account for extremely rare races. the solution is a huge hack: rather than blocking in the signal handler if the thread is dead, modify the signal mask of the saved context and return in order to prevent further signal handling by the dead thread. this allows the dead thread to continue decrementing the thread count (if it had not yet done so) and exiting, even while the live part of the program blocks for rsyscall. |
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| COPYING | ||
| COPYRIGHT | ||
| INSTALL | ||
| Makefile | ||
| README | ||
| WHATSNEW | ||
musl libc - a new standard library to power a new generation of
Linux-based devices. musl is lightweight, fast, simple, free, and
strives to be correct in the sense of standards-conformance and
safety.
musl is an alternative to glibc, eglibc, uClibc, dietlibc, and klibc.
For reasons why one might prefer musl, please see the FAQ and libc
comparison chart on the project website,
http://www.etalabs.net/musl/
For installation instructions, see the INSTALL file.
Please refer to the COPYRIGHT file for details on the copyright status
of code included in musl, and the COPYING file for the license (LGPL)
under which the library as a whole is distributed.
Greetings libc hackers!
This package is an _alpha_ release of musl, intended for the curious
and the adventurous. While it can be used to build a complete small
Linux system (musl is self-hosted on the system I use to develop it),
at this point doing so requires a lot of manual effort. Nonetheless, I
hope low-level Linux enthusiasts will try out building some compact
static binaries with musl using the provided gcc wrapper (which allows
you to link programs with musl on a "standard" glibc Linux system),
find whatever embarassing bugs I've let slip through, and provide
feedback on issues encountered building various software against musl.
Please visit #musl on Freenode IRC or contact me via email at dalias
AT etalabs DOT net for bug reports, support requests, or to get
involved in development. As this has been a one-person project so far,
mailing lists will be setup in due time on an as-needed basis.
Thank you for trying out musl.
Cheers,
Rich Felker / dalias