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[Bug libc/13425] New: Remove x86_64 Linux vsyscall page support
- From: "luto at mit dot edu" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: Mon, 21 Nov 2011 22:26:47 +0000
- Subject: [Bug libc/13425] New: Remove x86_64 Linux vsyscall page support
- Auto-submitted: auto-generated
http://sourceware.org/bugzilla/show_bug.cgi?id=13425
Bug #: 13425
Summary: Remove x86_64 Linux vsyscall page support
Product: glibc
Version: 2.14
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper.fsp@gmail.com
ReportedBy: luto@mit.edu
Classification: Unclassified
As of Linux 3.1, the vsyscall entry points (0xffffffffff600x00) are often
slower and never faster than real syscalls. They are also somewhat fragile in
that they can confuse various binary tracing systems (e.g. the Chromium
sandbox) and they cause some problems with UML.
It would be nice to support the vdso in static binaries, but, failing that,
glibc should just stop using the vsyscall page.
(Note: for getcpu on older kernels without a real sys_getcpu syscall, the
vsyscall page or vdso support might be mandatory. But the syscall should IMO
be preferred over the vsyscall entry.)
If this change is made, then vsyscall=none has a good chance of working :)
This is a continuation of bug 12813.
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