Bug 511444

Summary:	sys-fs/zfs-kmod-0.6.2-r5 with sys-kernel/gentoo-sources-3.14.4 - upon reading /proc/spl/kstat/zfs/arcstats - BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 in [<ffffffffa04618ac>] __kstat_create+0x66c/0x690 [spl]
Product:	Gentoo Linux	Reporter:	Matthias Maier <tamiko>
Component:	[OLD] Core system	Assignee:	Richard Yao (RETIRED) <ryao>
Status:	RESOLVED INVALID
Severity:	normal
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Attachments:	Full dmesg output with kernel oops emerge --info kernel configuration

Description Matthias Maier gentoo-dev

2014-05-25 12:06:05 UTC

With sys-fs/zfs-kmod-0.6.2-r5 (sys-fs/zfs-0.6.2-r5, sys-kernel/spl-0.6.2-r5) I encounter a NULL pointer dereference and Kernel Oops upon reading /proc/spl/kstat/zfs/arcstats (see attached dmesg).

This happens with sys-kernel/gentoo-sources-3.14.4, the currently stable version sys-kernel/gentoo-sources-3.12.13 is fine.

I also encounter some strange memory leak problems - slowly declining MemFree and MemAvailable by constant memory consumption from userland, and kernel (slab, buffer, cache) that I suspect are related to this. So this might be an indicator for a bigger problem with memory management - or memory accounting (which changed a bit in 3.14, e.g. new MemAvailable).

emerge --info and kernel configuration attached.

Reproducible: Always

Comment 1 Matthias Maier gentoo-dev

2014-05-25 12:07:00 UTC

Created attachment 377610 [details]
Full dmesg output with kernel oops

Comment 2 Matthias Maier gentoo-dev

2014-05-25 12:07:46 UTC

Created attachment 377612 [details]
emerge --info

Comment 3 Matthias Maier gentoo-dev

2014-05-25 12:09:21 UTC

Created attachment 377614 [details]
kernel configuration

Comment 4 Matthias Maier gentoo-dev

2014-05-25 21:34:51 UTC

Well, I tried to investigate a bit and I could not reproduce on a test setup. Later, upon completely rebuilding everything the kernel oops (and the memory consumption problem) do not show up any more. So, this was very likely a layer 8 problem.

Sorry for the noise.