Issue 10312: intcatcher() can deadlock (original) (raw)

Created on 2010-11-04 12:49 by hfuru, last changed 2022-04-11 14:57 by admin. This issue is now closed.

Messages (5)
msg120399 - (view)	Author: Hallvard B Furuseth (hfuru)	Date: 2010-11-04 12:49
Parser/intrcheck.c:intcatcher() can do FILE* operations, which can deadlock if the interrupt happens while a FILE* operation on the same FILE holds a mutex for the FILE. I've seen this happen elsewhere. It'd rather be a pity to remove Py_Exit(), so I suggest switch(interrupted++) gets a case 3 or 4: which does _exit(1), and 'interrupted = 0;' is moved there from case 2. Also 'interrupted' should be volatile sig_atomic_t, and the function should save/restore errno as in Issue 10311. BTW, you could use strlen(message) instead of sizeof(message)-1.
msg120845 - (view)	Author: Hallvard B Furuseth (hfuru)	Date: 2010-11-09 08:42
Sorry, my patch is useless if the OS calls the handler with the signal blocked. It should also unblock the signal before doing anything which can do FILE* operations. And set the handler again? Or just leave the next signal to abort the process? I dunno... Anyway, if you don't do that, just apply the save/restore of errno. Drop the 'if (errno != save_errno)' before restoring, that bit of paranoia was turned down in Issue10311.
msg221668 - (view)	Author: Mark Lawrence (BreamoreBoy) *	Date: 2014-06-27 00:05
intrcheck.c no longer exists in cpython so can this be closed "out of date"?
msg221677 - (view)	Author: PCManticore (Claudiu.Popa) *	Date: 2014-06-27 06:16
It's still in Python 2, though.
msg382080 - (view)	Author: Irit Katriel (iritkatriel) *	Date: 2020-11-29 17:21
This is a python 2-only issue.