The checks were removed in commit d693def4fd1c ("drm: Remove obsolete GEM and PRIME callbacks from struct drm_driver") and can lead to following kernel oops:
[ 139.449098] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 139.449110] #PF: supervisor read access in kernel mode [ 139.449113] #PF: error_code(0x0000) - not-present page [ 139.449116] PGD 0 P4D 0 [ 139.449121] Oops: 0000 [#1] PREEMPT SMP PTI [ 139.449126] CPU: 4 PID: 1181 Comm: Xorg Not tainted 5.11.2LEdoian #2 [ 139.449130] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z77-DS3H, BIOS F4 04/25/2012 [ 139.449133] RIP: 0010:drm_gem_handle_create_tail+0xcb/0x190 [drm] [ 139.449185] Code: 00 48 89 ef e8 06 b4 49 f7 45 85 e4 78 77 48 8d 6b 18 4c 89 ee 48 89 ef e8 c2 f5 00 00 89 c2 85 c0 75 3e 48 8b 83 40 01 00 00 <48> 8b 40 0 8 48 85 c0 74 0f 4c 89 ee 48 89 df e8 71 5d 87 f7 85 c0 [ 139.449190] RSP: 0018:ffffbe21c194bd28 EFLAGS: 00010246 [ 139.449194] RAX: 0000000000000000 RBX: ffff9da9b3caf078 RCX: 0000000000000000 [ 139.449197] RDX: 0000000000000000 RSI: ffffffffc039b893 RDI: 0000000000000000 [ 139.449199] RBP: ffff9da9b3caf090 R08: 0000000000000040 R09: ffff9da983b911c0 [ 139.449202] R10: ffff9da984749e00 R11: ffff9da9859bfc38 R12: 0000000000000007 [ 139.449204] R13: ffff9da9859bfc00 R14: ffff9da9859bfc50 R15: ffff9da9859bfc38 [ 139.449207] FS: 00007f6332a56900(0000) GS:ffff9daea7b00000(0000) knlGS:0000000000000000 [ 139.449211] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 139.449214] CR2: 0000000000000008 CR3: 00000001319b8005 CR4: 00000000001706e0 [ 139.449217] Call Trace: [ 139.449224] drm_gem_prime_fd_to_handle+0xff/0x1d0 [drm] [ 139.449274] ? drm_prime_destroy_file_private+0x20/0x20 [drm] [ 139.449323] drm_ioctl_kernel+0xac/0xf0 [drm] [ 139.449363] drm_ioctl+0x20f/0x3b0 [drm] [ 139.449403] ? drm_prime_destroy_file_private+0x20/0x20 [drm] [ 139.449454] radeon_drm_ioctl+0x49/0x80 [radeon] [ 139.449500] __x64_sys_ioctl+0x84/0xc0 [ 139.449507] do_syscall_64+0x33/0x40 [ 139.449514] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 139.449522] RIP: 0033:0x7f63330fbe6b [ 139.449526] Code: ff ff ff 85 c0 79 8b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f 0 ff ff 73 01 c3 48 8b 0d d5 af 0c 00 f7 d8 64 89 01 48 [ 139.449529] RSP: 002b:00007fff1e9c4438 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 139.449534] RAX: ffffffffffffffda RBX: 00007fff1e9c447c RCX: 00007f63330fbe6b [ 139.449537] RDX: 00007fff1e9c447c RSI: 00000000c00c642e RDI: 0000000000000012 [ 139.449539] RBP: 00000000c00c642e R08: 00007fff1e9c4520 R09: 00007f63331c7a60 [ 139.449542] R10: 00007f6329fb9ab0 R11: 0000000000000246 R12: 000055f69810ad40 [ 139.449544] R13: 0000000000000012 R14: 0000000000100000 R15: 00007fff1e9c4c20 [ 139.449549] Modules linked in: 8021q garp mrp bridge stp llc nls_iso8859_1 vfat fat fuse btrfs blake2b_generic xor raid6_pq libcrc32c crypto_user tun i2c_de v it87 hwmon_vid snd_seq snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio sg snd_hda_codec_hdmi virtio_balloon snd_hda_intel virtio_console snd_intel_ dspcfg soundwire_intel virtio_pci soundwire_generic_allocation soundwire_cadence virtio_blk snd_hda_codec intel_rapl_msr btusb intel_rapl_common virtio_net btr tl net_failover uvcvideo snd_usb_audio snd_hda_core btbcm x86_pkg_temp_thermal failover soundwire_bus btintel intel_powerclamp snd_soc_core coretemp snd_usbmid i_lib iTCO_wdt videobuf2_vmalloc bluetooth intel_pmc_bxt snd_hwdep kvm_intel videobuf2_memops snd_rawmidi snd_compress videobuf2_v4l2 ac97_bus snd_pcm_dmaengin e iTCO_vendor_support crct10dif_pclmul at24 crc32_pclmul videobuf2_common snd_seq_device mei_hdcp snd_pcm ghash_clmulni_intel kvm videodev aesni_intel crypto_s imd snd_timer snd cryptd mc ecdh_generic [ 139.449642] glue_helper rfkill soundcore joydev mousedev rapl ecc intel_cstate r8169 i2c_i801 intel_uncore atl1c realtek irqbypass mdio_devres mei_me libph y i2c_smbus mei mac_hid lpc_ich ext4 crc32c_generic crc16 mbcache jbd2 dm_mod ata_generic pata_acpi uas usb_storage sr_mod crc32c_intel serio_raw cdrom xhci_pc i pata_jmicron xhci_pci_renesas radeon usbhid i915 intel_gtt nouveau mxm_wmi wmi video i2c_algo_bit drm_ttm_helper ttm drm_kms_helper syscopyarea sysfillrect s ysimgblt fb_sys_fops cec drm agpgart [ 139.449707] CR2: 0000000000000008 [ 139.449710] ---[ end trace f5ce5774498d18e1 ]---
Signed-off-by: Pavel Turinský ledoian@kam.mff.cuni.cz Fixes: d693def4fd1c ("drm: Remove obsolete GEM and PRIME callbacks from struct drm_driver") Cc: stable@vger.kernel.org ---
This is a very symptomatic patch around issue I ran into. I do not know if the funcs property should ever be NULL. I basically restored all the checks that were removed in the mentioned commit. Unfortunately, I do not understand drm nor will I have time to delve into it in forseeable future.
drivers/gpu/drm/drm_gem.c | 20 ++++++++++---------- drivers/gpu/drm/drm_prime.c | 2 +- 2 files changed, 11 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 92f89cee213e..451f290c737c 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -249,7 +249,7 @@ drm_gem_object_release_handle(int id, void *ptr, void *data) struct drm_file *file_priv = data; struct drm_gem_object *obj = ptr;
- if (obj->funcs->close) + if (obj->funcs && obj->funcs->close) obj->funcs->close(obj, file_priv);
drm_gem_remove_prime_handles(obj, file_priv); @@ -401,7 +401,7 @@ drm_gem_handle_create_tail(struct drm_file *file_priv, if (ret) goto err_remove;
- if (obj->funcs->open) { + if (obj->funcs && obj->funcs->open) { ret = obj->funcs->open(obj, file_priv); if (ret) goto err_revoke; @@ -977,7 +977,7 @@ drm_gem_object_free(struct kref *kref) struct drm_gem_object *obj = container_of(kref, struct drm_gem_object, refcount);
- if (WARN_ON(!obj->funcs->free)) + if (!obj->funcs || WARN_ON(!obj->funcs->free)) return;
obj->funcs->free(obj); @@ -1079,7 +1079,7 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
vma->vm_private_data = obj;
- if (obj->funcs->mmap) { + if (obj->funcs && obj->funcs->mmap) { ret = obj->funcs->mmap(obj, vma); if (ret) { drm_gem_object_put(obj); @@ -1087,7 +1087,7 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, } WARN_ON(!(vma->vm_flags & VM_DONTEXPAND)); } else { - if (obj->funcs->vm_ops) + if (obj->funcs && obj->funcs->vm_ops) vma->vm_ops = obj->funcs->vm_ops; else { drm_gem_object_put(obj); @@ -1188,13 +1188,13 @@ void drm_gem_print_info(struct drm_printer *p, unsigned int indent, drm_printf_indent(p, indent, "imported=%s\n", obj->import_attach ? "yes" : "no");
- if (obj->funcs->print_info) + if (obj->funcs && obj->funcs->print_info) obj->funcs->print_info(p, indent, obj); }
int drm_gem_pin(struct drm_gem_object *obj) { - if (obj->funcs->pin) + if (obj->funcs && obj->funcs->pin) return obj->funcs->pin(obj); else return 0; @@ -1202,7 +1202,7 @@ int drm_gem_pin(struct drm_gem_object *obj)
void drm_gem_unpin(struct drm_gem_object *obj) { - if (obj->funcs->unpin) + if (obj->funcs && obj->funcs->unpin) obj->funcs->unpin(obj); }
@@ -1210,7 +1210,7 @@ int drm_gem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map) { int ret;
- if (!obj->funcs->vmap) + if (!obj->funcs || !obj->funcs->vmap) return -EOPNOTSUPP;
ret = obj->funcs->vmap(obj, map); @@ -1227,7 +1227,7 @@ void drm_gem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map) if (dma_buf_map_is_null(map)) return;
- if (obj->funcs->vunmap) + if (obj->funcs && obj->funcs->vunmap) obj->funcs->vunmap(obj, map);
/* Always set the mapping to NULL. Callers may rely on this. */ diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 7db55fce35d8..1566dcf417e2 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -620,7 +620,7 @@ struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach, if (WARN_ON(dir == DMA_NONE)) return ERR_PTR(-EINVAL);
- if (WARN_ON(!obj->funcs->get_sg_table)) + if (!obj->funcs || WARN_ON(!obj->funcs->get_sg_table)) return ERR_PTR(-ENOSYS);
sgt = obj->funcs->get_sg_table(obj);