Bug #69903 Stack corruption in vio_io_wait on Mac OS X

Submitted:	1 Aug 2013 20:44	Modified:	22 Apr 2015 13:21
Reporter:	Sergei Glushchenko	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Locking	Severity:	S1 (Critical)
Version:	5.6.12	OS:	MacOS
Assigned to:		CPU Architecture:	Any
Tags:	crash, stack corruption, vio_io_wait

Description:
vio_io_wait implemented on OS X using "select" system call. This call has well known limitation that it cannot handle file descriptor values greater than FD_SETSIZE (which is 1024 on my system). Moreover FD_SET for such a descriptor cause stack corruption.

How to repeat:
Read vio_io_wait implementation.

Suggested fix:
Use poll, or kevent, or define _DARWIN_UNLIMITED_SELECT and manage fd_set values manually.

Regression introduced by https://github.com/darnaut/mysql-server/commit/1c99912b98f200915f14797429de7fe99e94052b

Hello Sergei,

Thank you for the bug report.

Thanks,
Umesh

Also the analysis for tghe alleged fix is wrong. shutdown() breaks poll(), and it is not different on OSX

Noted in 5.7.8, 5.8.0 changelogs.

On OS X, the vio_io_wait() call could cause stack corruption for a
large number of file descriptors (more than FD_SETSIZE).

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