Don't leak or race in FreeBSD devstat collector #396
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Oh great, thanks! Unfortunately I've just merged a PR to change the metrics to const metrics so some conflicts need to be resolved. Can you rebase this? |
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Sure, will do tomorrow. |
The memory allocated by calloc was never freed. Since the devinfo struct never leaves the function, anyway, we might as well just allocate it on the stack.
Embedding 100 lines of code in a comment doesn't make for good reading, editing or code quality.
Querying the number of devices separately from the device list itself is racy. Devices may be added or removed between the two calls; and removed devices would lead to a segfault.
The devstat API expects us to reuse one devinfo for many invocations of devstat_getstats. In particular, it allocates and resizes memory referenced by devinfo.
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@discordianfish PTAL |
grobie
reviewed
Jan 5, 2017
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| // +build !nodevstat | |||
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grobie
approved these changes
Jan 5, 2017
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@discordianfish Already done in 9847257 |
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Gna.. github.. Thanks! |
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The FreeBSD devstat collector was leaking memory (calloc with no matching free as well as memory allocated by devstat_getdevs). It was also racing, by querying the number of devices and the actual list of devices separately.
The same flaws exist in the DragonflyBSD collector. Someone with access to a machine for testing might want to port the fixes over.