| Summary: | Potential race when generating gtypes (and more) | ||
|---|---|---|---|
| Product: | Telepathy | Reporter: | Ross Burton <ross> |
| Component: | mission-control | Assignee: | Simon McVittie <smcv> |
| Status: | RESOLVED FIXED | QA Contact: | Telepathy bugs list <telepathy-bugs> |
| Severity: | normal | ||
| Priority: | medium | Keywords: | patch |
| Version: | unspecified | ||
| Hardware: | Other | ||
| OS: | All | ||
| Whiteboard: | review? | ||
| i915 platform: | i915 features: | ||
| Bug Depends on: | |||
| Bug Blocks: | 69600 | ||
| Attachments: |
Patch
codegen: avoid generating more than one thing in the same command |
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|
Description
Ross Burton
2013-09-16 23:47:57 UTC
(In reply to comment #0) > set_file_contents() uses a predictable name for it's temporary file when > writing atomically, and (at least) mission-control can hit a race in > parallel builds. (https://bugzilla.yoctoproject.org/show_bug.cgi?id=5184) > > Luckily this is known as telepathy-glib fixed these in > 36c2a545c9c1d1cc6db205bfc33d980d29b0a0f6 so the same fixes need to be > applied to mission-control. Indeed. I thought I'd fixed this in all projects, but apparently I missed MC. > (fwiw, I've also a proof-of-concept patch for the predicable name issue) I don't think this is really a problem: we're writing to a user-controlled directory, so we're not vulnerable to symlink attacks or anything. If we just avoided the "generate the same file twice" anti-pattern, it'd be fine. Created attachment 86851 [details] [review] Patch This patch was sent to fix the issue in our builds but sadly the author didn't submit it here, so I'm doing it for them. Created attachment 93055 [details] [review] codegen: avoid generating more than one thing in the same command As with telepathy-glib commit 36c2a545c9, a rule like this: _gen/x.c _gen/x.h: prerequisites $(AM_V_GEN)x-generator doesn't consider x.c and x.h together. Instead, it expands to two rules, one to generate x.c and one to generate x.h, which happen to run the same commands. This means that in the worst case, you can end up running x-generator twice in parallel, and they'll race with each other and overwrite or delete each other's output. Updated version of a patch from Ross Burton, taking into account that we now generate a separate header for the gtk-doc. I use the gtk-doc header as the one that "matters", because it's the last to be generated. --- I'm proposing this patch even though I'm about to delete the code-generation stuff, because (a) I just encountered it, and (b) I would like a `git revert` of that deletion to bring us back to a correct state. Not using Ross' patch directly because we now generate more files than we used to. Comment on attachment 93055 [details] [review] codegen: avoid generating more than one thing in the same command Review of attachment 93055 [details] [review]: ----------------------------------------------------------------- ++ Fixed in git for 5.17.0. Not fixed for 5.16 yet. Also 5.16.2 |
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