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Investigate why the module reader is trying to read past the end of a memory region on Firefox for Android. #239
Description
In commit 9de255d, I fixed a livelock regression that was introduced when I accidentally deleted a zero-length-read check from a read_exact() style function.
However, the livelock occurred in MappedModuleMemoryReader::read_exact_at() (link), which generally shouldn't be reading past the end of a memory region anyway.
Also -- This didn't show up in any of the testing I did on Ubuntu, nor did it show up in our m-w integration tests even on aarch64-linux-android -- it only showed up when m-w was integrated into Firefox for Android and run manually on my Pixel 8.
It might be worth investigating why this happened, as there may be some underlying bug in m-w.
(Note that I am filing this here instead of on Firefox's Bugzilla, as I suspect this is actually a bug in m-w and is not unique to Firefox -- Firefox is just an example of software that is complex enough to surface the bug.)
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gabrielesvelto commentedon Sep 17, 2026
I have a Pixel 6a, maybe it's good enough to reproduce this issue.
schopin-mozilla commentedon Sep 23, 2026
I'm wondering if the root cause isn't the same as https://bugzilla.mozilla.org/show_bug.cgi?id=2074595