[Bug]spurious PEBS NMI triggered by non-precise events
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
intel |
Fix Released
|
Undecided
|
Unassigned | ||
linux (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
The following perf command can easily trigger the pebs warning or spurious NMI error on Skylake/
sudo perf record -e 'cpu/umask=
Also NMI watchdog must be enabled to reproduce this issue.
Here is the dump.
[ 113.452176] Call Trace:
[ 113.452178] <NMI> [<ffffffff813c3
[ 113.452188] [<ffffffff810a4
[ 113.452190] [<ffffffff810a4
[ 113.452193] [<ffffffff8100f
[ 113.452197] [<ffffffff8100c
[ 113.452204] [<ffffffff81063
[ 113.452208] [<ffffffff811f2
[ 113.452211] [<ffffffff811f2
[ 113.452216] [<ffffffff81483
[ 113.452218] [<ffffffff81483
[ 113.452224] [<ffffffff81005
[ 113.452230] [<ffffffff81031
[ 113.452233] [<ffffffff81031
[ 113.452236] [<ffffffff81031
[ 113.452240] [<ffffffff817ae
[ 113.452243] [<ffffffff81063
[ 113.452246] [<ffffffff81063
[ 113.452249] [<ffffffff81063
[ 113.452250] <<EOE>> <IRQ> [<ffffffff81006
[ 113.452255] [<ffffffff81006
[ 113.452258] [<ffffffff81007
[ 113.452263] [<ffffffff81199
[ 113.452267] [<ffffffff8119c
[ 113.452270] [<ffffffff8119c
[ 113.452273] [<ffffffff8110f
[ 113.452276] [<ffffffff81110
[ 113.452278] [<ffffffff81199
[ 113.452283] [<ffffffff81051
[ 113.452286] [<ffffffff817af
[ 113.452290] [<ffffffff817ad
[ 113.452291] <EOI> [<ffffffff81199
[ 113.452298] [<ffffffff81123
[ 113.452300] [<ffffffff81123
[ 113.452303] [<ffffffff81199
[ 113.452306] [<ffffffff81197
[ 113.452308] [<ffffffff8119c
[ 113.452311] [<ffffffff81197
[ 113.452313] [<ffffffff81197
[ 113.452315] [<ffffffff81197
[ 113.452318] [<ffffffff81197
[ 113.452320] [<ffffffff81197
[ 113.452322] [<ffffffff811a0
[ 113.452326] [<ffffffff8134d
[ 113.452330] [<ffffffff8124a
[ 113.452334] [<ffffffff81036
[ 113.452336] [<ffffffff8124a
[ 113.452338] [<ffffffff817ac
[ 113.452340] --[ end trace aef202839fe9a71d ]--
[ 113.452611] Uhhuh. NMI received for unknown reason 2d on CPU 2.
[ 113.453880] Do you have a strange power saving mode enabled?
One commit from v4.6 fix this issue, please back port it to 16.04
c3d266c perf/x86/intel: Fix PEBS warning by only restoring active PMU in pmi