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Created on 2010-08-06 14:43 by gdb, last changed 2022-04-11 14:57 by admin. This issue is now closed.
| Files | ||||
|---|---|---|---|---|
| File name | Uploaded | Description | Edit | |
| signals.patch | gdb, 2010-08-06 14:43 | Clear pending signals from child process after fork() | ||
| issue9535-clear_signals_afterfork-gps01.diff | gregory.p.smith, 2011-01-04 03:46 | review | ||
| Messages (7) | |||
|---|---|---|---|
| msg113104 - (view) | Author: Greg Brockman (gdb) | Date: 2010-08-06 14:43 | |
Upon os.fork(), pending signals are inherited by the child process. This can be demonstrated by pressing C-c in the middle of the
following program:
"""
import os, sys, time, threading
def do_fork():
while True:
if not os.fork():
print 'hello from child'
sys.exit(0)
time.sleep(0.5)
t = threading.Thread(target=do_fork)
t.start()
t.join()
"""
Right after os.fork(), each child will raise a KeyboardInterrupt exception.
This behavior is different from the semantics of POSIX fork(), where child processes do not inherit their parents' pending signals.
Attached is a first stab at a patch to fix this issue. Please let me know what you think!
|
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| msg125245 - (view) | Author: Antoine Pitrou (pitrou) *  |
Date: 2011-01-03 21:26 | |
Shouldn't the clearing of signals be done in PyOS_AfterFork() directly? Gregory, what do you think about the semantics? |
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| msg125246 - (view) | Author: Gregory P. Smith (gregory.p.smith) * |
Date: 2011-01-03 21:40 | |
Doing this makes sense, i'm taking to closer look to see where it should be done. |
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| msg125290 - (view) | Author: Gregory P. Smith (gregory.p.smith) * |
Date: 2011-01-04 03:46 | |
Yes I'd do it in PyOS_AfterFork. Simpler patch based on gdb's attached. This could also use a test but as it involves signals and race conditions, making a deterministic test for this is difficult as it. If we added testing hooks to the python interpreter internals to allow test code to do things like set the signal tripped flags directly it's be much easier. |
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| msg125305 - (view) | Author: Antoine Pitrou (pitrou) * |
Date: 2011-01-04 11:11 | |
> Yes I'd do it in PyOS_AfterFork. Simpler patch based on gdb's > attached. Private functions shouldn't use the PyXX_CamelCase() convention :) Otherwise, looks good. |
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| msg175315 - (view) | Author: Roundup Robot (python-dev)  |
Date: 2012-11-11 04:34 | |
New changeset ba45976c2801 by Gregory P. Smith in branch '3.2': Fixes issue #9535: Fix pending signals that have been received but not http://hg.python.org/cpython/rev/ba45976c2801 New changeset c7d6cd3c27b9 by Gregory P. Smith in branch '3.3': Fixes issue #9535: Fix pending signals that have been received but not http://hg.python.org/cpython/rev/c7d6cd3c27b9 New changeset 41280973921a by Gregory P. Smith in branch 'default': Fixes issue #9535: Fix pending signals that have been received but not http://hg.python.org/cpython/rev/41280973921a |
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| msg175316 - (view) | Author: Roundup Robot (python-dev) |
Date: 2012-11-11 04:38 | |
New changeset 9b711422c98f by Gregory P. Smith in branch '2.7': Fixes issue #9535: Fix pending signals that have been received but not yet http://hg.python.org/cpython/rev/9b711422c98f |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:57:05 | admin | set | github: 53744 |
| 2012-11-11 04:39:09 | gregory.p.smith | set | status: open -> closed resolution: fixed |
| 2012-11-11 04:38:29 | python-dev | set | messages: + msg175316 |
| 2012-11-11 04:34:49 | python-dev | set | nosy:
+ python-dev messages: + msg175315 |
| 2011-01-04 11:11:21 | pitrou | set | messages: + msg125305 |
| 2011-01-04 03:46:39 | gregory.p.smith | set | files:
+ issue9535-clear_signals_afterfork-gps01.diff messages: + msg125290 keywords: + needs review |
| 2011-01-03 21:40:04 | gregory.p.smith | set | assignee: gregory.p.smith messages: + msg125246 |
| 2011-01-03 21:26:17 | pitrou | set | nosy:
+ pitrou messages: + msg125245 |
| 2010-09-03 23:45:39 | pitrou | set | nosy:
+ gregory.p.smith stage: patch review components: + Interpreter Core, - Extension Modules versions: + Python 3.1, Python 3.2, - Python 2.6, Python 2.5 |
| 2010-08-06 14:43:13 | gdb | create | |