1377681 - Crash in mozilla::net::CacheFile::Truncate: MOZ_RELEASE_ASSERT(maxInputChunk <= newLastChunk + 1)

Status: RESOLVED FIXED

(Core :: Networking: Cache, defect)

Description

[Nicolas B. Pierron [:nbp]]

This bug was filed from the Socorro interface and is 
report bp-4e1cdfeb-b979-4bf9-8682-1f98f0170701.
=============================================================

Based on the fact that this bug started spiking on the same time frame as the bytecode cache experiment, this might likely be related to Bug 900784.

Comment 1

[Michal Novotny [:michal]]

It definitely is related because CacheFile::Truncate is used only by alternative streams.

Comment 2

[Michal Novotny [:michal]]

If you could reproduce the crash, having log would help a lot.

Comment 3

[Nicolas B. Pierron [:nbp]]

Could this bug be a duplicate of Bug 1372993?

Comment 4

[Michal Novotny [:michal]]

(In reply to Nicolas B. Pierron [:nbp] from comment #3)
> Could this bug be a duplicate of Bug 1372993?

No, AFAICS bug 1372993 is duplicate of other 2 bugs that were already fixed.

Comment 5

[Asa Dotzler [:asa]]

I just hit this crash today's build on windows scrolling a twitter page. I also have a dozen pinned tabs so maybe one of them refreshed or something. Sorry no clear steps to reproduce. Will keep trying.

Comment 6

[Michal Novotny [:michal]]

After doing some changes in the cache code to hit this code more often I was able to reproduce it. The problem is at http://searchfox.org/mozilla-central/rev/238406d4c1b3f147522ce0a45a4c6f84a8115781/netwerk/cache2/CacheFileInputStream.h#43 where -1 is casted to the same type as return value of CacheChunk::Index() which is uint32_t. So the method returns UINT32_MAX instead of -1.

Comment 7

[Michal Novotny [:michal]]

Attachment: fix

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/f97eaa4aadb2
Crash in mozilla::net::CacheFile::Truncate: MOZ_RELEASE_ASSERT(maxInputChunk <= newLastChunk + 1), r=jduell

Comment 9

[Valentin Gosu [:valentin]]

Great catch!

Comment 10

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/integration/autoland/rev/f97eaa4aadb2

Comment 11

[Ekanan Ketunuti]

https://hg.mozilla.org/mozilla-central/rev/f97eaa4aadb2

Comment 12

[Nicholas Nethercote [inactive]]

This is a topcrash in the Nightly 20170708030206 build, but is gone in the Nightly 20170709030204 build. Excellent!