The attached program (found by syzkaller) triggers the following warning in the 3.18 amd64-generic kernel:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 13580 at /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:144 drm_setversion+0x1e0/0x36b()
No drm_driver.set_busid() implementation provided by vgem_driver. Use drm_dev_set_unique() to set the unique name explicitly.
Modules linked in: hci_vhci algif_skcipher cmac algif_hash af_alg i2c_dev uinput sr_mod cdrom bluetooth zram fuse cfg80211 nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables virtio_net i2c_piix4 snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device ppp_async ppp_generic slhc tun
CPU: 0 PID: 13580 Comm: warn_drm_setver Tainted: G        W      3.18.0 #19
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 0000000000000009 000000009d1b1a9d ffff8800236a7c28 ffffffff81b50047
 ffff8800236a7c00 ffffffff9d1b1a9d ffff8800236a7ca0 ffff880021230080
 ffff8800236a7c78 ffffffff810636af 0000000000000000 ffffffff8152b3bf
Call Trace:
 [<     inline     >] __dump_stack /mnt/host/source/src/third_party/kernel/v3.18/lib/dump_stack.c:15
 [<ffffffff81b50047>] dump_stack+0x74/0xb3 /mnt/host/source/src/third_party/kernel/v3.18/lib/dump_stack.c:50
 [<ffffffff810636af>] warn_slowpath_common+0xa9/0xc7 /mnt/host/source/src/third_party/kernel/v3.18/kernel/panic.c:441
 [<     inline     >] ? drm_set_busid /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:141
 [<ffffffff8152b3bf>] ? drm_setversion+0x1e0/0x36b /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:400
 [<ffffffff81063739>] warn_slowpath_fmt+0x6c/0x87 /mnt/host/source/src/third_party/kernel/v3.18/kernel/panic.c:453
 [<     inline     >] drm_set_busid /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:141
 [<ffffffff8152b3bf>] drm_setversion+0x1e0/0x36b /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:400
 [<ffffffff8152b06e>] drm_ioctl+0x6f3/0x78f /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:755
 [<ffffffff8152b1df>] ? drm_getunique+0xd5/0xd5 /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:70
 [<     inline     >] ? fatal_signal_pending /mnt/host/source/src/third_party/kernel/v3.18/include/linux/sched.h:2792
 [<ffffffff8105292f>] ? __do_page_fault+0x4a5/0x5de /mnt/host/source/src/third_party/kernel/v3.18/arch/x86/mm/fault.c:1246
 [<ffffffff8152a97b>] ? drm_version+0x16a/0x16a /mnt/host/source/src/third_party/kernel/v3.18/drivers/gpu/drm/drm_ioctl.c:486
 [<     inline     >] vfs_ioctl /mnt/host/source/src/third_party/kernel/v3.18/fs/ioctl.c:43
 [<ffffffff811e8178>] do_vfs_ioctl+0x6e5/0x71e /mnt/host/source/src/third_party/kernel/v3.18/fs/ioctl.c:598
 [<ffffffff811e4076>] ? final_putname+0x7d/0x82 /mnt/host/source/src/third_party/kernel/v3.18/fs/namei.c:129
 [<ffffffff811f6b13>] ? __fget_light+0xd5/0xe0 /mnt/host/source/src/third_party/kernel/v3.18/fs/file.c:692
 [<     inline     >] SYSC_ioctl /mnt/host/source/src/third_party/kernel/v3.18/fs/ioctl.c:613
 [<ffffffff811e8225>] SyS_ioctl+0x74/0xb3 /mnt/host/source/src/third_party/kernel/v3.18/fs/ioctl.c:604
 [<ffffffff81b57cdc>] system_call_fastpath+0x1c/0x21 /mnt/host/source/src/third_party/kernel/v3.18/arch/x86/kernel/entry_64.S:436
---[ end trace 77e9c0fc14a42a41 ]---

Need to backport https://github.com/torvalds/linux/commit/fa2f97dd33c2c32a06a5ea7f6e87af06a2e26baa to fix that.
 

Deleted: warn_drm_setversion.c 847 bytes

warn_drm_setversion.c 847 bytes View Download