I have tried to grab details about the kernel panic stack trace to make it easier for Joerg to identify and fix the issue. I have downloaded the latest Kubuntu Live ISO image which is based on kernel 4.2.0. I have changed the boot parameters to boot with intel_iommu=on. I was able to capture the kernel panic with slow motion video recording. The hard lockup appears to occur when calling "flush_context".
Testing with: Intel I7 980 MSI Big Bang X-Power (X58) Here are the images of the kernel panic. http://s31.postimg.org/5s0zzdu63/Screenshot_from_2016_04_23_00_04_32.png http://s31.postimg.org/juris3oxn/Screenshot_from_2016_04_23_00_47_00.png Exactly same kernel panic happens on Intel DX58SO board with a Xeon processor when using intel_iommu=on commandline parameter. On Sat, Apr 23, 2016 at 12:35 AM, Dheeraj CVR <[email protected]> wrote: > I am currently running the following 2 setups. > > Intel Xeon X5670 > Intel DX58SO (x58) > > Intel I7 980 > MSI Big Bang X-Power (x58) > > I am using IOMMU along with VFIO to passthrough a VGA card on both of my > setups. Everything worked fine till kernel 4.1, but after the introduction > of "iommu/vt-d: Make root entry visible for hardware right after > allocation", both the boards no longer boot with "intel_iommu=on" > commandline parameter. > > The logs show the following: > DMAR: RMRR base: 0x000000bf7e8000 end: 0x000000bf7fffff > DMAR: ATSR flags: 0x0 > DMAR: dmar0: Using Queued invalidation > ------------[ cut here ]------------ > WARNING: CPU: 4: PID: 1 at /home/dhiru1602/linux-git/kernel/watchdog.c:311 > watchdog_overflow_callback+0x79/0xa0() > Watchdog detected hard LOCKUP on cpu 4 > Modules Linked in: > CPU: 4 PID: 1 Comm: swapper/0 Tainted: G I > 4.2.0-iommu-test > > The kernel panic occurs very early in the boot process and I was not able > to grab the full kernel panic log. > > I have reverted the patch and recompiled the kernel. I was able to boot > fine on both the boards with intel_iommu=on and I was able to see the IOMMU > groups. > > On a sidenote, Both the boards have broken interrupt remapping and the > vendors have not provided BIOS updates to fix this problem. There was a > report for the Intel board made on the Intel Community Forums here: > https://communities.intel.com/thread/44752 but there hasn't been an > updated BIOS released by Intel to fix this issue. > > Please let me know if more information is needed to diagnose this issue. > -- > Regards, > Dheeraj CVR. > -- Regards, Dheeraj CVR.
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