1732325 - mmap in SharedMemory::FindFreeAddressSpace should use MAP_NORESERVE

Status: RESOLVED FIXED

(Core :: IPC, defect)

Description

[Petr Sumbera]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:92.0) Gecko/20100101 Firefox/92.0

Steps to reproduce:

The issue is similar to:

https://bugzilla.mozilla.org/show_bug.cgi?id=1527597

Sometimes we see in system logs:

Sep 23 09:48:06 solaris genunix: [ID 531226 kern.warning] WARNING:
anon_resv: process 1461 attempted to allocate 4194304 pages of anon memory

The issue is that:

https://searchfox.org/mozilla-central/rev/f62d42b1d98e67dc3da05d586f71103df02b8c4a/ipc/chromium/src/base/shared_memory_posix.cc#521

doesn't use: MAP_NORESERVE

Fix should be to just add MAP_NORESERVE to mmap() call in FindFreeAddressSpace. We don't need to force the system to allocate swap space, because the mapping is temporary. It is destroyed on next line in source code by munmap() call.

Comment 1

[Petr Sumbera]

Attachment: Bug 1732325 - SharedMemory::FindFreeAddressSpace should use MAP_NORESERVE

Comment 2

[Timea Cernea [:tbabos][inactive]]

Moving this over to the correct component based on Bug 1527597 and setting it up as new. Thank you for the reported issues and for working on patches to fix them!

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/86f46322fd29
SharedMemory::FindFreeAddressSpace should use MAP_NORESERVE r=glandium

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/86f46322fd29