__ (___()'`; Rusty's Remarkably Unreliable Guide to Lguest /, /` - or, A Young Coder's Illustrated Hypervisor \\"--\\ http://lguest.ozlabs.org Lguest is designed to be a minimal 32-bit x86 hypervisor for the Linux kernel, for Linux developers and users to experiment with virtualization with the minimum of complexity. Nonetheless, it should have sufficient features to make it useful for specific tasks, and, of course, you are encouraged to fork and enhance it (see drivers/lguest/README). Features: - Kernel module which runs in a normal kernel. - Simple I/O model for communication. - Simple program to create new guests. - Logo contains cute puppies: http://lguest.ozlabs.org Developer features: - Fun to hack on. - No ABI: being tied to a specific kernel anyway, you can change anything. - Many opportunities for improvement or feature implementation. Running Lguest: - The easiest way to run lguest is to use same kernel as guest and host. You can configure them differently, but usually it's easiest not to. You will need to configure your kernel with the following options: "Processor type and features": "Paravirtualized guest support" = Y "Lguest guest support" = Y "High Memory Support" = off/4GB "Alignment value to which kernel should be aligned" = 0x100000 (CONFIG_PARAVIRT=y, CONFIG_LGUEST_GUEST=y, CONFIG_HIGHMEM64G=n and CONFIG_PHYSICAL_ALIGN=0x100000) "Device Drivers": "Block devices" "Virtio block driver" = M/Y "Network device support" "Universal TUN/TAP device driver support" = M/Y "Virtio network driver" = M/Y (CONFIG_VIRTIO_BLK=m, CONFIG_VIRTIO_NET=m and CONFIG_TUN=m) "Virtualization" "Linux hypervisor example code" = M/Y (CONFIG_LGUEST=m) - A tool called "lguest" is available in this directory: type "make" to build it. If you didn't build your kernel in-tree, use "make O=". - Create or find a root disk image. There are several useful ones around, such as the xm-test tiny root image at http://xm-test.xensource.com/ramdisks/initrd-1.1-i386.img For more serious work, I usually use a distribution ISO image and install it under qemu, then make multiple copies: dd if=/dev/zero of=rootfile bs=1M count=2048 qemu -cdrom image.iso -hda rootfile -net user -net nic -boot d Make sure that you install a getty on /dev/hvc0 if you want to log in on the console! - "modprobe lg" if you built it as a module. - Run an lguest as root: tools/lguest/lguest 64 vmlinux --tunnet=192.168.19.1 \ --block=rootfile root=/dev/vda Explanation: 64: the amount of memory to use, in MB. vmlinux: the kernel image found in the top of your build directory. You can also use a standard bzImage. --tunnet=192.168.19.1: configures a "tap" device for networking with this IP address. --block=rootfile: a file or block device which becomes /dev/vda inside the guest. root=/dev/vda: this (and anything else on the command line) are kernel boot parameters. - Configuring networking. I usually have the host masquerade, using "iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE" and "echo 1 > /proc/sys/net/ipv4/ip_forward". In this example, I would configure eth0 inside the guest at 192.168.19.2. Another method is to bridge the tap device to an external interface using --tunnet=bridge:, and perhaps run dhcp on the guest to obtain an IP address. The bridge needs to be configured first: this option simply adds the tap interface to it. A simple example on my system: ifconfig eth0 0.0.0.0 brctl addbr lg0 ifconfig lg0 up brctl addif lg0 eth0 dhclient lg0 Then use --tunnet=bridge:lg0 when launching the guest. See: http://www.linuxfoundation.org/collaborate/workgroups/networking/bridge for general information on how to get bridging to work. - Random number generation. Using the --rng option will provide a /dev/hwrng in the guest that will read from the host's /dev/random. Use this option in conjunction with rng-tools (see ../hw_random.txt) to provide entropy to the guest kernel's /dev/random. There is a helpful mailing list at http://ozlabs.org/mailman/listinfo/lguest Good luck! Rusty Russell rusty@rustcorp.com.au. ='20'>20space:mode:
authorMaarten Lankhorst <maarten.lankhorst@linux.intel.com>2017-01-31 10:25:25 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2017-01-31 13:41:46 +0100
commit92c715fca907686f5298220ece53423e38ba3aed (patch)
tree286158fdad04c9b54955350abb95d4f1c0dc860a /include/trace/events/cgroup.h
parente6e7b48b295afa5a5ab440de0a94d9ad8b3ce2d0 (diff)
drm/atomic: Fix double free in drm_atomic_state_default_clear
drm_atomic_helper_page_flip and drm_atomic_ioctl set their own events in crtc_state->event. But when it's set the event is freed in 2 places. Solve this by only freeing the event in the atomic ioctl when it allocated its own event. This has been broken twice. The first time when the code was introduced, but only in the corner case when an event is allocated, but more crtc's were included by atomic check and then failing. This can mostly happen when you do an atomic modeset in i915 and the display clock is changed, which forces all crtc's to be included to the state. This has been broken worse by adding in-fences support, which caused the double free to be done unconditionally. [IGT] kms_rotation_crc: starting subtest primary-rotation-180 ============================================================================= BUG kmalloc-128 (Tainted: G U ): Object already free ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Allocated in drm_atomic_helper_setup_commit+0x285/0x2f0 [drm_kms_helper] age=0 cpu=3 pid=1529 ___slab_alloc+0x308/0x3b0 __slab_alloc+0xd/0x20 kmem_cache_alloc_trace+0x92/0x1c0 drm_atomic_helper_setup_commit+0x285/0x2f0 [drm_kms_helper] intel_atomic_commit+0x35/0x4f0 [i915] drm_atomic_commit+0x46/0x50 [drm] drm_mode_atomic_ioctl+0x7d4/0xab0 [drm] drm_ioctl+0x2b3/0x490 [drm] do_vfs_ioctl+0x69c/0x700 SyS_ioctl+0x4e/0x80 entry_SYSCALL_64_fastpath+0x13/0x94 INFO: Freed in drm_event_cancel_free+0xa3/0xb0 [drm] age=0 cpu=3 pid=1529 __slab_free+0x48/0x2e0 kfree+0x159/0x1a0 drm_event_cancel_free+0xa3/0xb0 [drm] drm_mode_atomic_ioctl+0x86d/0xab0 [drm] drm_ioctl+0x2b3/0x490 [drm] do_vfs_ioctl+0x69c/0x700 SyS_ioctl+0x4e/0x80 entry_SYSCALL_64_fastpath+0x13/0x94 INFO: Slab 0xffffde1f0997b080 objects=17 used=2 fp=0xffff92fb65ec2578 flags=0x200000000008101 INFO: Object 0xffff92fb65ec2578 @offset=1400 fp=0xffff92fb65ec2ae8 Redzone ffff92fb65ec2570: bb bb bb bb bb bb bb bb ........ Object ffff92fb65ec2578: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec2588: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec2598: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec25a8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec25b8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec25c8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec25d8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff92fb65ec25e8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. Redzone ffff92fb65ec25f8: bb bb bb bb bb bb bb bb ........ Padding ffff92fb65ec2738: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ CPU: 3 PID: 180 Comm: kworker/3:2 Tainted: G BU 4.10.0-rc6-patser+ #5039 Hardware name: /NUC5PPYB, BIOS PYBSWCEL.86A.0031.2015.0601.1712 06/01/2015 Workqueue: events intel_atomic_helper_free_state [i915] Call Trace: dump_stack+0x4d/0x6d print_trailer+0x20c/0x220 free_debug_processing+0x1c6/0x330 ? drm_atomic_state_default_clear+0xf7/0x1c0 [drm] __slab_free+0x48/0x2e0 ? drm_atomic_state_default_clear+0xf7/0x1c0 [drm] kfree+0x159/0x1a0 drm_atomic_state_default_clear+0xf7/0x1c0 [drm] ? drm_atomic_state_clear+0x30/0x30 [drm] intel_atomic_state_clear+0xd/0x20 [i915] drm_atomic_state_clear+0x1a/0x30 [drm] __drm_atomic_state_free+0x13/0x60 [drm] intel_atomic_helper_free_state+0x5d/0x70 [i915] process_one_work+0x260/0x4a0 worker_thread+0x2d1/0x4f0 kthread+0x127/0x130 ? process_one_work+0x4a0/0x4a0 ? kthread_stop+0x120/0x120 ret_from_fork+0x29/0x40 FIX kmalloc-128: Object at 0xffff92fb65ec2578 not freed Fixes: 3b24f7d67581 ("drm/atomic: Add struct drm_crtc_commit to track async updates") Fixes: 9626014258a5 ("drm/fence: add in-fences support") Cc: <stable@vger.kernel.org> # v4.8+ Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1485854725-27640-1-git-send-email-maarten.lankhorst@linux.intel.com
Diffstat (limited to 'include/trace/events/cgroup.h')