[tor-bugs] #31614 [Core Tor/Tor]: Implement clean_up_backtrace_handler()
Tor Bug Tracker & Wiki
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Fri Sep 13 06:56:18 UTC 2019
#31614: Implement clean_up_backtrace_handler()
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Reporter: teor | Owner: teor
Type: defect | Status:
| needs_revision
Priority: Medium | Milestone: Tor:
| 0.4.2.x-final
Component: Core Tor/Tor | Version: Tor:
| 0.3.5.1-alpha
Severity: Normal | Resolution:
Keywords: consider-backport-after-042-stable, | Actual Points: 0.2
consider-backport-if-needed, diagnostics, |
042-should, 035-backport-maybe, 040-backport- |
maybe, 041-backport-maybe, regression, |
BugSmashFund |
Parent ID: | Points: 0.2
Reviewer: dgoulet | Sponsor:
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Comment (by teor):
You're right, there are a bunch of nasty race conditions here.
This is what we need to fix:
1. Always lock the mutex before using cb_buf (there are some places where
we don't do this)
2. Lock the mutex before adding or removing signal handlers (might not be
strictly required, but it makes reasoning about locks easier)
3. Abort if destroying the mutex fails (doesn't save us from undefined
behaviour, but does notify us when it happens)
We could also
4. Lock a mutex before logging anywhere in the err module (this could
cause more issues than it solves)
The best way to do this might be to put cb_buf in its own file, and use
accessor functions.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31614#comment:11>
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