Hi Duncan, Thx for your lengthy answer. I'm using Kubuntu Wily with custom built kernel 4.3.0 (but the same happens when booting the ubuntu kernel). I don't use apparmor and selinux is disabled according to getenforce.
I use kubuntu-backports repository, so as for versions, I'm at plasma 5.4.3, framework 5.15 and apps 15.08.2 Best regards, Martin On Wed, Nov 18, 2015 at 2:31 AM, Duncan <[email protected]> wrote: > Martin van Es posted on Tue, 17 Nov 2015 12:50:35 +0100 as excerpted: > > > Hi, > > > > I've searched high and low but couldn't find a satisfactory answer to > > the question: why do all KDE/Plasma apps warn "Failed to establish > > shared memory mapping, will fallback to private memory -- memory usage > > will increase"? > > > > I have /dev/shm mounted (tmpfs) and /dev/shm has drwxrwxrwt mode bits, > > /run/shm is a symbolic link to /dev/shm > > > > What I find curious is that when I start the same app as root it doesn't > > show the warning, but I can't for the life of me understand why I can't > > establish shared memory as a user and can as root? > > > > /dev/shm contains file that have pulse-shm in their name, and ipcs -a > > shows me many shared memory segments? > > So why can't KDE apps establish shared memory? > > This /may/ be a result of some sort of security measures your distro has > setup. Unfortunately you didn't mention the distro and version you're > running, but I've not seen such warnings here, on Gentoo/~amd64. > > Also, you didn't mention what version of kde/plasma. With many distros > switching to kde-frameworks-5 and plasma-5, while others are still on > kde4, and even where the switch to 5 has taken place, individual apps may > remain kde4 based for the time being, this could be important, as well. > > FWIW, kde4 here, tho I have most of a minimal kde-frameworks-5/plasma-5 > installed for easier testing, lacking only the few bits that can't be > installed along with the kde4 versions, so I can keep what's configured > and working, while quickly switching to the new versions for testing when > I have time. > > As for the warning itself, I don't believe it actually refers to shm. > > KDE (at least kde4, and kde3 before it, and I'd guess plasma5 does > something similar) normally starts up using a special initialization > sequence that starts one process and then forks several others off it, > doing it in such a way that they can share the same library (elf *.so > shared objects) address space, etc, thus allowing shared libraries with > faster launching and lower memory usage, even where security measures > such as memory-space randomization would normally force separate > applications to use their own separately randomized library addresses for > the same libraries, making it impossible to share the same library > address space and increasing memory usage. > > I'd guess that this isn't working in your case for whatever reason, very > possibly due to additional security measures taken by your distro. If > so, it really doesn't have anything to do with tmpfs or /dev/shm and its > permissions, but rather, with whatever additional security measures your > distro is enforcing. > > -- > Duncan - List replies preferred. No HTML msgs. > "Every nonfree program has a lord, a master -- > and if you use the program, he is your master." Richard Stallman > > ___________________________________________________ > This message is from the kde mailing list. > Account management: https://mail.kde.org/mailman/listinfo/kde. > Archives: http://lists.kde.org/. > More info: http://www.kde.org/faq.html. -- If 'but' was any useful, it would be a logic operator
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