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---Problem Description---
When run as normal user, 'perf record ls' fails with:
Perf session creation failed.
The command runs successfully when run as root.
---uname output---
Linux ubuntu 3.16.0-16-generic #22-Ubuntu SMP Wed Sep 17 18:45:43 UTC 2014
ppc64le ppc64le ppc64le GNU/Linux
Machine Type = POWER8E pvr 004b 0201
> Maynard,
>
> Can you check if /proc/sys/kernel/kptr_restrict has 1 in it on your
> system ?
Yes, the value is '1'.
>
> On my system it does have 1 and I can repro. Following seems to
> fix:
> echo 0 > /proc/sys/kernel/kptr_restrict
Yes, changing it to '0' does "fix" it, although that shouldn't be
necessary, as you know. So something is broken.
I am able to repro with 3.17.0-rc4 based mainline perf tool.
I suspect that the change in behavior was introduced unintentionally by
this upstream commit. machine__create_kernel_maps() now calls
machine__get_kernel_start_addr() which checks the kptr_restrict state.
---
commit a93f0e551af9e194db38bfe16001e17a3a1d189a
Author: Simon Que <s...@chromium.org>
Date: Mon Jun 16 11:32:09 2014 -0700
perf symbols: Get kernel start address by symbol name
This is being fixed by a recent upstream commit:
https://lkml.org/lkml/2014/9/27/26
Will Ubuntu pick that fix up automatically ?
** Affects: linux (Ubuntu)
Importance: Undecided
Status: Confirmed
** Tags: architecture-ppc64le bugnameltc-116381 severity-medium
targetmilestone-inin---
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'perf record' fails with "Perf session creation failed"
https://bugs.launchpad.net/bugs/1375441
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