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Thu, 14 Aug 2025 12:51:09 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 7C7UG73bnWhhXQAAD6G6ig (envelope-from ); Thu, 14 Aug 2025 12:51:09 +0000 Message-ID: Date: Thu, 14 Aug 2025 14:51:09 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 RESEND 1/3] drm/shmem-helper: Import dmabuf without mapping its sg_table To: =?UTF-8?Q?Christian_K=C3=B6nig?= , Shixiong Ou Cc: Maarten Lankhorst , Maxime Ripard , David Airlie , Simona Vetter , Sean Paul , Jocelyn Falempe , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Shixiong Ou References: <20250522070714.439824-1-oushixiong1025@163.com> <7d974eaa-d8a4-4430-a999-7b06c4e17a81@163.com> <9792c6c3-a2b8-4b2b-b5ba-fba19b153e21@suse.de> <47ba5d7b-dd1c-4f19-92cb-523b60f1e876@suse.de> <805acaca-3b91-438d-b842-25c055fd898c@amd.com> Content-Language: en-US From: Thomas Zimmermann Autocrypt: addr=tzimmermann@suse.de; keydata= xsBNBFs50uABCADEHPidWt974CaxBVbrIBwqcq/WURinJ3+2WlIrKWspiP83vfZKaXhFYsdg XH47fDVbPPj+d6tQrw5lPQCyqjwrCPYnq3WlIBnGPJ4/jreTL6V+qfKRDlGLWFjZcsrPJGE0 BeB5BbqP5erN1qylK9i3gPoQjXGhpBpQYwRrEyQyjuvk+Ev0K1Jc5tVDeJAuau3TGNgah4Yc hdHm3bkPjz9EErV85RwvImQ1dptvx6s7xzwXTgGAsaYZsL8WCwDaTuqFa1d1jjlaxg6+tZsB 9GluwvIhSezPgnEmimZDkGnZRRSFiGP8yjqTjjWuf0bSj5rUnTGiyLyRZRNGcXmu6hjlABEB AAHNJ1Rob21hcyBaaW1tZXJtYW5uIDx0emltbWVybWFubkBzdXNlLmRlPsLAjgQTAQgAOAIb AwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftODH AAoJEGgNwR1TC3ojx1wH/0hKGWugiqDgLNXLRD/4TfHBEKmxIrmfu9Z5t7vwUKfwhFL6hqvo lXPJJKQpQ2z8+X2vZm/slsLn7J1yjrOsoJhKABDi+3QWWSGkaGwRJAdPVVyJMfJRNNNIKwVb U6B1BkX2XDKDGffF4TxlOpSQzdtNI/9gleOoUA8+jy8knnDYzjBNOZqLG2FuTdicBXblz0Mf vg41gd9kCwYXDnD91rJU8tzylXv03E75NCaTxTM+FBXPmsAVYQ4GYhhgFt8S2UWMoaaABLDe 7l5FdnLdDEcbmd8uLU2CaG4W2cLrUaI4jz2XbkcPQkqTQ3EB67hYkjiEE6Zy3ggOitiQGcqp j//OwE0EWznS4AEIAMYmP4M/V+T5RY5at/g7rUdNsLhWv1APYrh9RQefODYHrNRHUE9eosYb T6XMryR9hT8XlGOYRwKWwiQBoWSDiTMo/Xi29jUnn4BXfI2px2DTXwc22LKtLAgTRjP+qbU6 3Y0xnQN29UGDbYgyyK51DW3H0If2a3JNsheAAK+Xc9baj0LGIc8T9uiEWHBnCH+RdhgATnWW GKdDegUR5BkDfDg5O/FISymJBHx2Dyoklv5g4BzkgqTqwmaYzsl8UxZKvbaxq0zbehDda8lv hFXodNFMAgTLJlLuDYOGLK2AwbrS3Sp0AEbkpdJBb44qVlGm5bApZouHeJ/+n+7r12+lqdsA EQEAAcLAdgQYAQgAIAIbDBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftOH6AAoJEGgNwR1T C3ojVSkIALpAPkIJPQoURPb1VWjh34l0HlglmYHvZszJWTXYwavHR8+k6Baa6H7ufXNQtThR yIxJrQLW6rV5lm7TjhffEhxVCn37+cg0zZ3j7zIsSS0rx/aMwi6VhFJA5hfn3T0TtrijKP4A SAQO9xD1Zk9/61JWk8OysuIh7MXkl0fxbRKWE93XeQBhIJHQfnc+YBLprdnxR446Sh8Wn/2D Ya8cavuWf2zrB6cZurs048xe0UbSW5AOSo4V9M0jzYI4nZqTmPxYyXbm30Kvmz0rYVRaitYJ 4kyYYMhuULvrJDMjZRvaNe52tkKAvMevcGdt38H4KSVXAylqyQOW5zvPc4/sq9c= In-Reply-To: <805acaca-3b91-438d-b842-25c055fd898c@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_ALL(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; FREEMAIL_ENVRCPT(0.00)[163.com,gmail.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_TO(0.00)[amd.com,163.com]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[linux.intel.com,kernel.org,gmail.com,ffwll.ch,poorly.run,redhat.com,lists.freedesktop.org,vger.kernel.org,kylinos.cn]; RCPT_COUNT_SEVEN(0.00)[11]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[bootlin.com:url,suse.de:mid] X-Spam-Flag: NO X-Spam-Level: X-Spam-Score: -4.30 Hi Christian Am 14.08.25 um 12:22 schrieb Christian König: > On 13.08.25 16:06, Thomas Zimmermann wrote: >> Hi >> >> Am 13.08.25 um 15:35 schrieb Christian König: >>> On 13.08.25 14:16, Thomas Zimmermann wrote: >>>> In addition: >>>> >>>>>> Here udl just silently assumes that it got a vaddr, but that isn't necessarily the case. Drivers amdgpu (or radeon, nouveau etc...) can return an io addr as well. >>>>> That's a union of the two pointer types. [1] Using them interchangeably has worked so far (*) and should work here as well. As I said in the other mail, ttm_bo_vmap() never bothers to pin the pages in place and amdgpu might relocated them shortly after. >>>> AFAICT with the old code we ran dma_buf_pin_on_map() at some point. Could we do this in the new version as well? >>> Ah, yes that could be it. So basically the buffer moves and because of that the vmap is unmapped. >>> >>> It would probably be a good idea to call dma_buf_pin() from drm_gem_dmabuf_vmap() before calling drm_gem_vmap_locked(). >>> >>> Should be trivial since we already have the dma_buf object and the necessary lock is held as well. >> The attached patch fixes the problem on my test system. It further integrates well with the existing logic, so changes are minimal. Any comments before I send it out for review? > Mhm that looks more or less like what I had in mind initially as well, but I was convinced that this is probably not the best idea. What do you mean by 'convinced'? Was there a review of a previous patch? > > We have exposed the dma_buf_pin()/dma_buf_unpin() functions for exactly that use case. So we should probably make use of that. > > Either by pinning in the exporter, e.g. drm_gem_dmabuf_vmap()/drm_gem_dmabuf_vunmap() or even lower level (amdgpu/ttm) or in the importer. > > Not doing it in TTM was intentional since we have use cases where kmap/vmap is only temporary valid until you drop the dma_resv lock again. > > Doing it in the importer would be the cleanest approach, but that means changing the semantics of the DMA-buf API including audition all imports using dma_buf_vmap()... so a lot of work. I don't fully understand your comment. We used to pin these buffer before. The proposed change is just an extension to the existing semantics of dma_buf_map_attachment(). Admittedly, I did not check the full kernel codebase if DMA_NONE is a valid input for any implementation of map_dma_buf. Would that be valid semantics? > > So that leaves either drm_gem_dmabuf_vmap()/drm_gem_dmabuf_vunmap() or amdgpu. I think drm_gem_dmabuf_vmap()/drm_gem_dmabuf_vunmap() is the cleanest and schould have no impact on other drivers. If we pull the pin/unpin into gem-shmem helpers, what about that test with  dma_buf_pin_on_map()? Do we need that in gem-shmem as well? [1] [1] https://elixir.bootlin.com/linux/v6.16/source/drivers/dma-buf/dma-buf.c#L1115 BTW, I always thought that the dma-buf vmap implementation guarantees that the buffer won't move. If so, that would imply that drm_gem_dmabuf_vmap() would be the right place. Another point to keep in mind is that other drivers besides amdgpu might also be affected. Most drivers appear to be using drm_gem_prime_export(), which ends up with drm_gem_dmabuf_vmap(). So a fix there would benefit them. Best regards Thomas > > Regards, > Christian. > >> Best regards >> Thomas >> >>> Regards, >>> Christian. >>> >>>> [1] https://elixir.bootlin.com/linux/v6.16/source/drivers/dma-buf/dma-buf.c#L1115 >>>> >>>> Best regards >>>> Thomas >>>> >>>>> [1] https://elixir.bootlin.com/linux/v6.16/source/include/linux/iosys-map.h#L110 >>>>> >>>>> Best regards >>>>> Thomas >>>>> >>>>> (*) White lie: we had problems on exotic architectures, such as sparc, but never on x86. >>>>> >>>>> >>>>>> Regards, >>>>>> Christian. >>>>>> >>>>>>> Best regards >>>>>>> Thomas >>>>>>> >>>>>>>> Best regards, >>>>>>>> Shixiong >>>>>>>> >>>>>>>> >>>>>>>>> [  168.785445] BUG: unable to handle page fault for address: ffffc9012b800000 >>>>>>>>> [  168.792311] #PF: supervisor read access in kernel mode >>>>>>>>> [  168.797452] #PF: error_code(0x0000) - not-present page >>>>>>>>> [  168.802586] PGD 100000067 P4D 100000067 PUD 0 >>>>>>>>> [  168.807042] Oops: Oops: 0000 [#1] SMP KASAN PTI >>>>>>>>> [  168.811573] CPU: 2 UID: 1000 PID: 2380 Comm: KMS thread Tainted: G            E       6.16.0-rc5-1-default+ #4080 PREEMPT(voluntary) >>>>>>>>> [  168.823537] Tainted: [E]=UNSIGNED_MODULE >>>>>>>>> [  168.827458] Hardware name: System manufacturer System Product Name/Z170-A, BIOS 3802 03/15/2018 >>>>>>>>> [  168.836125] RIP: 0010:udl_compress_hline16+0x219/0x940 [udl] >>>>>>>>> [  168.841779] Code: 0f b6 34 28 4c 89 d8 49 d3 e5 83 e0 07 4d 01 dd 83 f9 01 0f 84 4a 03 00 00 83 c0 03 40 38 f0 7c 09 40 84 f6 0f 85 82 05 00 00 <41> 8b 03 4c 63 7c 24 78 4c 89 5c 24 08 89 c6 41 89 c4 c1 e8 08 >>>>>>>>> c1 >>>>>>>>> [  168.860476] RSP: 0018:ffff88811c7e75c0 EFLAGS: 00010246 >>>>>>>>> [  168.865697] RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000002 >>>>>>>>> [  168.872815] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000100 >>>>>>>>> [  168.879934] RBP: dffffc0000000000 R08: ffff8881082efe00 R09: ffff8881082e0000 >>>>>>>>> [  168.887046] R10: 0000000000000002 R11: ffffc9012b800000 R12: ffff88811c7e76f8 >>>>>>>>> [  168.894155] R13: ffffc9012b800400 R14: ffff8881082e0007 R15: 0000000000000000 >>>>>>>>> [  168.901266] FS:  00007f4685f3b6c0(0000) GS:ffff88846c690000(0000) knlGS:0000000000000000 >>>>>>>>> [  168.909330] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>>>>>> [  168.915058] CR2: ffffc9012b800000 CR3: 0000000117944004 CR4: 00000000003706f0 >>>>>>>>> [  168.922170] Call Trace: >>>>>>>>> [  168.924616]  >>>>>>>>> [  168.926714]  ? validate_chain+0x24e/0x5e0 >>>>>>>>> [  168.930718]  ? __lock_acquire+0x568/0xae0 >>>>>>>>> [  168.934725]  udl_render_hline+0x165/0x33b [udl] >>>>>>>>> [  168.939256]  ? __pfx_udl_render_hline+0x10/0x10 [udl] >>>>>>>>> [  168.944297]  ? local_clock_noinstr+0xb/0x100 >>>>>>>>> [  168.948557]  ? __lock_release.isra.0+0x16c/0x2e0 >>>>>>>>> [  168.953162]  ? mark_held_locks+0x40/0x70 >>>>>>>>> [  168.957077]  ? lockdep_hardirqs_on_prepare.part.0+0x92/0x170 >>>>>>>>> [  168.962721] udl_primary_plane_helper_atomic_update+0x432/0x670 [udl] >>>>>>>>> [  168.969145]  ? __pfx_udl_primary_plane_helper_atomic_update+0x10/0x10 [udl] >>>>>>>>> [  168.976089]  ? __pfx___drm_dev_dbg+0x10/0x10 >>>>>>>>> [  168.980357]  ? drm_atomic_helper_calc_timestamping_constants+0x141/0x200 >>>>>>>>> [  168.987044]  ? drm_atomic_helper_commit_planes+0x3b6/0x1030 >>>>>>>>> [  168.992599] drm_atomic_helper_commit_planes+0x3b6/0x1030 >>>>>>>>> [  168.997987]  drm_atomic_helper_commit_tail+0x41/0xb0 >>>>>>>>> [  169.002943]  commit_tail+0x204/0x330 >>>>>>>>> [  169.006513]  drm_atomic_helper_commit+0x242/0x2e0 >>>>>>>>> [  169.011203]  ? __pfx_drm_atomic_helper_commit+0x10/0x10 >>>>>>>>> [  169.016413]  drm_atomic_commit+0x1e1/0x290 >>>>>>>>> [  169.020500]  ? prepare_signaling+0x355/0xda0 >>>>>>>>> [  169.024769]  ? __pfx_drm_atomic_commit+0x10/0x10 >>>>>>>>> [  169.029372]  ? __pfx___drm_printfn_info+0x10/0x10 >>>>>>>>> [  169.034069]  drm_mode_atomic_ioctl+0x8ff/0xe40 >>>>>>>>> [  169.038510]  ? __pfx_drm_mode_atomic_ioctl+0x10/0x10 >>>>>>>>> [  169.043466]  ? find_held_lock+0x2b/0x80 >>>>>>>>> [  169.047295]  ? __lock_acquire+0x568/0xae0 >>>>>>>>> [  169.051293]  ? mark_usage+0x65/0x180 >>>>>>>>> [  169.054870]  ? __pfx_drm_mode_atomic_ioctl+0x10/0x10 >>>>>>>>> [  169.059823]  ? do_raw_spin_unlock+0x55/0x230 >>>>>>>>> [  169.064081]  ? drm_is_current_master+0x26/0x30 >>>>>>>>> [  169.068517]  ? __pfx_drm_mode_atomic_ioctl+0x10/0x10 >>>>>>>>> [  169.073465]  drm_ioctl_kernel+0x141/0x2b0 >>>>>>>>> [  169.077468]  ? __pfx_drm_ioctl_kernel+0x10/0x10 >>>>>>>>> [  169.081987]  ? lock_release.part.0+0x47/0x90 >>>>>>>>> [  169.086249]  drm_ioctl+0x481/0xb50 >>>>>>>>> [  169.089653]  ? __pfx_drm_mode_atomic_ioctl+0x10/0x10 >>>>>>>>> [  169.094610]  ? __pfx_drm_ioctl+0x10/0x10 >>>>>>>>> [  169.098525]  ? find_held_lock+0x2b/0x80 >>>>>>>>> [  169.102356]  ? lock_release.part.0+0x47/0x90 >>>>>>>>> [  169.106621]  ? __fget_files+0x1aa/0x2f0 >>>>>>>>> [  169.110450]  ? __fget_files+0x1b4/0x2f0 >>>>>>>>> [  169.114281]  __x64_sys_ioctl+0x135/0x1c0 >>>>>>>>> [  169.118201]  do_syscall_64+0x68/0x2a0 >>>>>>>>> [  169.121856]  entry_SYSCALL_64_after_hwframe+0x76/0x7e >>>>>>>>> [  169.126892] RIP: 0033:0x7f469391a53f >>>>>>>>> [  169.130460] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 18 48 8b 44 24 18 64 48 2b 04 25 28 00 >>>>>>>>> 00 >>>>>>>>> [  169.149151] RSP: 002b:00007f4685f39a80 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 >>>>>>>>> [  169.156703] RAX: ffffffffffffffda RBX: 00007f465c002da0 RCX: 00007f469391a53f >>>>>>>>> [  169.163868] RDX: 00007f4685f39b20 RSI: 00000000c03864bc RDI: 0000000000000010 >>>>>>>>> [  169.171029] RBP: 00007f4685f39b20 R08: 0000000000001310 R09: 00007f465c044cf0 >>>>>>>>> [  169.178194] R10: 0000000000000002 R11: 0000000000000246 R12: 00000000c03864bc >>>>>>>>> [  169.185358] R13: 0000000000000010 R14: 00007f465c0284b0 R15: 00007f45d402b110 >>>>>>>>> [  169.192525]  >>>>>>>>> [  169.194732] Modules linked in: udl(E) snd_seq_dummy(E) snd_hrtimer(E) snd_seq(E) snd_seq_device(E) af_packet(E) nf_tables(E) iptable_filter(E) binfmt_misc(E) intel_rapl_msr(E) nls_iso8859_1(E) eeepc_wmi(E) nls >>>>>>>>> _cp437(E) intel_rapl_common(E) snd_hda_codec_realtek(E) asus_wmi(E) iTCO_wdt(E) vfat(E) ee1004(E) snd_hda_codec_generic(E) sparse_keymap(E) x86_pkg_temp_thermal(E) iTCO_vendor_support(E) snd_hda_scodec_component( >>>>>>>>> E) intel_powerclamp(E) snd_hda_codec_hdmi(E) platform_profile(E) fat(E) e1000e(E) i2c_i801(E) ptp(E) battery(E) snd_hda_intel(E) i2c_smbus(E) snd_intel_dspcfg(E) mxm_wmi(E) rfkill(E) wmi_bmof(E) intel_wmi_thunder >>>>>>>>> bolt(E) coretemp(E) pps_core(E) i2c_mux(E) pcspkr(E) snd_hda_codec(E) xfs(E) snd_hda_core(E) snd_hwdep(E) snd_pcm(E) snd_timer(E) snd(E) soundcore(E) mei_me(E) acpi_pad(E) button(E) mei(E) joydev(E) nvme_fabrics( >>>>>>>>> E) loop(E) fuse(E) efi_pstore(E) dm_mod(E) configfs(E) nfnetlink(E) ip_tables(E) x_tables(E) amdgpu(E) amdxcp(E) i2c_algo_bit(E) drm_ttm_helper(E) ttm(E) drm_exec(E) hid_generic(E) >>>>>>>>> [  169.194874]  gpu_sched(E) drm_suballoc_helper(E) ghash_clmulni_intel(E) sha512_ssse3(E) video(E) sha1_ssse3(E) aesni_intel(E) usbhid(E) drm_panel_backlight_quirks(E) drm_buddy(E) drm_display_helper(E) cec(E) w >>>>>>>>> mi(E) btrfs(E) blake2b_generic(E) xor(E) raid6_pq(E) msr(E) i2c_dev(E) efivarfs(E) dmi_sysfs(E) >>>>>>>>> [  169.311501] CR2: ffffc9012b800000 >>>>>>>>> [  169.314835] ---[ end trace 0000000000000000 ]--- >>>>>>>>> [  169.434549] RIP: 0010:udl_compress_hline16+0x219/0x940 [udl] >>>>>>>>> [  169.440237] Code: 0f b6 34 28 4c 89 d8 49 d3 e5 83 e0 07 4d 01 dd 83 f9 01 0f 84 4a 03 00 00 83 c0 03 40 38 f0 7c 09 40 84 f6 0f 85 82 05 00 00 <41> 8b 03 4c 63 7c 24 78 4c 89 5c 24 08 89 c6 41 89 c4 c1 e8 08 >>>>>>>>> c1 >>>>>>>>> [  169.459062] RSP: 0018:ffff88811c7e75c0 EFLAGS: 00010246 >>>>>>>>> [  169.464309] RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000002 >>>>>>>>> [  169.471474] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000100 >>>>>>>>> [  169.478635] RBP: dffffc0000000000 R08: ffff8881082efe00 R09: ffff8881082e0000 >>>>>>>>> [  169.485800] R10: 0000000000000002 R11: ffffc9012b800000 R12: ffff88811c7e76f8 >>>>>>>>> [  169.492962] R13: ffffc9012b800400 R14: ffff8881082e0007 R15: 0000000000000000 >>>>>>>>> [  169.500126] FS:  00007f4685f3b6c0(0000) GS:ffff88846c690000(0000) knlGS:0000000000000000 >>>>>>>>> [  169.508246] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>>>>>> [  169.514014] CR2: ffffc9012b800000 CR3: 0000000117944004 CR4: 00000000003706f0 >>>>>>>>> [  169.521180] note: KMS thread[2380] exited with irqs disabled >>>>>>>>> [  175.343111] ================================================================== >>>>>>>>> [  175.350342] BUG: KASAN: slab-use-after-free in mutex_can_spin_on_owner+0x1a6/0x1c0 >>>>>>>>> [  175.357886] Read of size 4 at addr ffff8881172daff4 by task kworker/5:0/49 >>>>>>>>> [  175.364738] >>>>>>>>> [  175.366235] CPU: 5 UID: 0 PID: 49 Comm: kworker/5:0 Tainted: G      D     E       6.16.0-rc5-1-default+ #4080 PREEMPT(voluntary) >>>>>>>>> [  175.366240] Tainted: [D]=DIE, [E]=UNSIGNED_MODULE >>>>>>>>> [  175.366242] Hardware name: System manufacturer System Product Name/Z170-A, BIOS 3802 03/15/2018 >>>>>>>>> [  175.366244] Workqueue: events output_poll_execute >>>>>>>>> [  175.366249] Call Trace: >>>>>>>>> [  175.366251]  >>>>>>>>> [  175.366254]  dump_stack_lvl+0x68/0x90 >>>>>>>>> [  175.366259]  ? mutex_can_spin_on_owner+0x1a6/0x1c0 >>>>>>>>> [  175.366261] print_address_description.constprop.0+0x88/0x380 >>>>>>>>> [  175.366266]  ? lock_acquire+0xf2/0x140 >>>>>>>>> [  175.366269]  ? mutex_can_spin_on_owner+0x1a6/0x1c0 >>>>>>>>> [  175.366272]  print_report+0xf8/0x1e2 >>>>>>>>> [  175.366275]  ? __virt_addr_valid+0x22e/0x500 >>>>>>>>> [  175.366279]  ? kasan_addr_to_slab+0x9/0x90 >>>>>>>>> [  175.366282]  ? mutex_can_spin_on_owner+0x1a6/0x1c0 >>>>>>>>> [  175.366284]  kasan_report+0xd8/0x190 >>>>>>>>> [  175.366288]  ? mutex_can_spin_on_owner+0x1a6/0x1c0 >>>>>>>>> [  175.366294]  mutex_can_spin_on_owner+0x1a6/0x1c0 >>>>>>>>> [  175.366297]  __ww_mutex_lock.constprop.0+0x2f8/0x34d0 >>>>>>>>> [  175.366301]  ? do_raw_spin_trylock+0xa2/0x160 >>>>>>>>> [  175.366304]  ? __pfx_do_raw_spin_trylock+0x10/0x10 >>>>>>>>> [  175.366308]  ? get_nohz_timer_target+0x28/0x3d0 >>>>>>>>> [  175.366311]  ? modeset_lock+0x3c6/0x640 >>>>>>>>> [  175.366316]  ? __pfx___ww_mutex_lock.constprop.0+0x10/0x10 >>>>>>>>> [  175.366320]  ? rcu_is_watching+0x11/0xb0 >>>>>>>>> [  175.366323]  ? timerqueue_add+0x154/0x3c0 >>>>>>>>> [  175.366328]  ? __hrtimer_start_range_ns+0x2e1/0x750 >>>>>>>>> [  175.366331]  ? rcu_is_watching+0x11/0xb0 >>>>>>>>> [  175.366334]  ? lock_acquired+0xb6/0xf0 >>>>>>>>> [  175.366337]  ? rcu_is_watching+0x11/0xb0 >>>>>>>>> [  175.366340]  ? rcu_is_watching+0x11/0xb0 >>>>>>>>> [  175.366342]  ? drm_helper_probe_detect_ctx+0x6d/0x1a0 >>>>>>>>> [  175.366345]  ? lock_acquire+0xf2/0x140 >>>>>>>>> [  175.366349]  ? ww_mutex_lock+0x27/0x150 >>>>>>>>> [  175.366352]  ? drm_helper_probe_detect_ctx+0x6d/0x1a0 >>>>>>>>> [  175.366355]  ww_mutex_lock+0x27/0x150 >>>>>>>>> [  175.366358]  modeset_lock+0x3c6/0x640 >>>>>>>>> [  175.366362]  drm_helper_probe_detect_ctx+0xa6/0x1a0 >>>>>>>>> [  175.366366]  ? __pfx_drm_helper_probe_detect_ctx+0x10/0x10 >>>>>>>>> [  175.366375]  ? __pfx_drm_connector_list_iter_next+0x10/0x10 >>>>>>>>> [  175.366381]  output_poll_execute+0x29b/0x760 >>>>>>>>> [  175.366387]  ? trace_hardirqs_on+0x14/0x150 >>>>>>>>> [  175.366391]  ? __pfx_output_poll_execute+0x10/0x10 >>>>>>>>> [  175.366396]  process_one_work+0x7b5/0x1390 >>>>>>>>> [  175.366404]  ? __pfx_process_one_work+0x10/0x10 >>>>>>>>> [  175.366409]  ? assign_work+0x156/0x390 >>>>>>>>> [  175.366413]  worker_thread+0x58d/0xf60 >>>>>>>>> [  175.366420]  ? __pfx_worker_thread+0x10/0x10 >>>>>>>>> [  175.366422]  kthread+0x370/0x720 >>>>>>>>> [  175.366425]  ? __pfx_kthread+0x10/0x10 >>>>>>>>> [  175.366428]  ? local_clock_noinstr+0x56/0x100 >>>>>>>>> [  175.366431]  ? local_clock+0x11/0x30 >>>>>>>>> [  175.366433]  ? __lock_release.isra.0+0x16c/0x2e0 >>>>>>>>> [  175.366437]  ? rcu_is_watching+0x11/0xb0 >>>>>>>>> [  175.366439]  ? lockdep_hardirqs_on_prepare.part.0+0x92/0x170 >>>>>>>>> [  175.366442]  ? __pfx_kthread+0x10/0x10 >>>>>>>>> [  175.366445]  ret_from_fork+0x1f4/0x2f0 >>>>>>>>> [  175.366448]  ? __pfx_kthread+0x10/0x10 >>>>>>>>> [  175.366450]  ret_from_fork_asm+0x1a/0x30 >>>>>>>>> [  175.366459]  >>>>>>>>> [  175.366460] >>>>>>>>> [  175.632772] Allocated by task 2342: >>>>>>>>> [  175.636282]  kasan_save_stack+0x1c/0x40 >>>>>>>>> [  175.640137]  kasan_save_track+0x10/0x30 >>>>>>>>> [  175.643992]  __kasan_slab_alloc+0x5f/0x70 >>>>>>>>> [  175.648023]  kmem_cache_alloc_node_noprof+0x13a/0x380 >>>>>>>>> [  175.653097]  dup_task_struct+0x32/0x730 >>>>>>>>> [  175.656952]  copy_process+0x2d8/0x5380 >>>>>>>>> [  175.660720]  kernel_clone+0x9f/0x5e0 >>>>>>>>> [  175.664318]  __do_sys_clone3+0x135/0x180 >>>>>>>>> [  175.668258]  do_syscall_64+0x68/0x2a0 >>>>>>>>> [  175.671940]  entry_SYSCALL_64_after_hwframe+0x76/0x7e >>>>>>>>> [  175.677014] >>>>>>>>> [  175.678520] Freed by task 0: >>>>>>>>> [  175.681418]  kasan_save_stack+0x1c/0x40 >>>>>>>>> [  175.685273]  kasan_save_track+0x10/0x30 >>>>>>>>> [  175.689130]  kasan_save_free_info+0x37/0x70 >>>>>>>>> [  175.693333]  __kasan_slab_free+0x33/0x40 >>>>>>>>> [  175.697278]  kmem_cache_free+0x10b/0x4d0 >>>>>>>>> [  175.701221]  delayed_put_task_struct+0x15e/0x1e0 >>>>>>>>> [  175.705858]  rcu_do_batch+0x2e3/0xb30 >>>>>>>>> [  175.709542]  rcu_core+0x51d/0xb60 >>>>>>>>> [  175.712873]  handle_softirqs+0x1a2/0x6b0 >>>>>>>>> [  175.716817]  __irq_exit_rcu+0xf7/0x160 >>>>>>>>> [  175.720585]  irq_exit_rcu+0xa/0x30 >>>>>>>>> [  175.724006]  sysvec_apic_timer_interrupt+0x9d/0xc0 >>>>>>>>> [  175.728820]  asm_sysvec_apic_timer_interrupt+0x16/0x20 >>>>>>>>> [  175.733980] >>>>>>>>> [  175.735486] Last potentially related work creation: >>>>>>>>> [  175.740385]  kasan_save_stack+0x1c/0x40 >>>>>>>>> [  175.744243]  kasan_record_aux_stack+0x88/0xa0 >>>>>>>>> [  175.748618]  __call_rcu_common.constprop.0+0x77/0x850 >>>>>>>>> [  175.753693]  __schedule+0x887/0x1d00 >>>>>>>>> [  175.757287]  schedule+0xd0/0x260 >>>>>>>>> [  175.760533]  smpboot_thread_fn+0x583/0x7a0 >>>>>>>>> [  175.764650]  kthread+0x370/0x720 >>>>>>>>> [  175.767896]  ret_from_fork+0x1f4/0x2f0 >>>>>>>>> [  175.771665]  ret_from_fork_asm+0x1a/0x30 >>>>>>>>> [  175.775608] >>>>>>>>> [  175.777113] Second to last potentially related work creation: >>>>>>>>> [  175.782886]  kasan_save_stack+0x1c/0x40 >>>>>>>>> [  175.786739]  kasan_record_aux_stack+0x88/0xa0 >>>>>>>>> [  175.791118]  task_work_add+0x1b1/0x270 >>>>>>>>> [  175.794886]  sched_tick+0x226/0x6f0 >>>>>>>>> [  175.798394]  update_process_times+0xe9/0x1f0 >>>>>>>>> [  175.802685]  tick_nohz_handler+0x1a6/0x4b0 >>>>>>>>> [  175.806801]  __hrtimer_run_queues+0x161/0x960 >>>>>>>>> [  175.811181]  hrtimer_interrupt+0x33e/0x880 >>>>>>>>> [  175.815295]  __sysvec_apic_timer_interrupt+0xf6/0x390 >>>>>>>>> [  175.820370]  sysvec_apic_timer_interrupt+0x98/0xc0 >>>>>>>>> [  175.825183]  asm_sysvec_apic_timer_interrupt+0x16/0x20 >>>>>>>>> [  175.830343] >>>>>>>>> [  175.831849] The buggy address belongs to the object at ffff8881172dafc0 >>>>>>>>> [  175.831849]  which belongs to the cache task_struct of size 11968 >>>>>>>>> [  175.844582] The buggy address is located 52 bytes inside of >>>>>>>>> [  175.844582]  freed 11968-byte region [ffff8881172dafc0, ffff8881172dde80) >>>>>>>>> [  175.856969] >>>>>>>>> [  175.858474] The buggy address belongs to the physical page: >>>>>>>>> [  175.864070] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1172d8 >>>>>>>>> [  175.872104] head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 >>>>>>>>> [  175.879788] memcg:ffff88811068a301 >>>>>>>>> [  175.883209] anon flags: 0x2ffff800000040(head|node=0|zone=2|lastcpupid=0x1ffff) >>>>>>>>> [  175.890547] page_type: f5(slab) >>>>>>>>> [  175.893706] raw: 002ffff800000040 ffff888100930500 0000000000000000 0000000000000001 >>>>>>>>> [  175.901479] raw: 0000000000000000 0000000000020002 00000000f5000000 ffff88811068a301 >>>>>>>>> [  175.909249] head: 002ffff800000040 ffff888100930500 0000000000000000 0000000000000001 >>>>>>>>> [  175.917109] head: 0000000000000000 0000000000020002 00000000f5000000 ffff88811068a301 >>>>>>>>> [  175.924968] head: 002ffff800000003 ffffea00045cb601 00000000ffffffff 00000000ffffffff >>>>>>>>> [  175.932827] head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 >>>>>>>>> [  175.940685] page dumped because: kasan: bad access detected >>>>>>>>> [  175.946283] >>>>>>>>> [  175.947787] Memory state around the buggy address: >>>>>>>>> [  175.952603]  ffff8881172dae80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >>>>>>>>> [  175.959854]  ffff8881172daf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>>>>>>> [  175.967101] >ffff8881172daf80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >>>>>>>>> [ 175.974353] ^ >>>>>>>>> [  175.981256]  ffff8881172db000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>>>>>>> [  175.988504]  ffff8881172db080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>>>>>>> [  175.995755] ================================================================== >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Am 22.05.25 um 09:07 schrieb oushixiong1025@163.com: >>>>>>>>>> From: Shixiong Ou >>>>>>>>>> >>>>>>>>>> [WHY] >>>>>>>>>> 1. Drivers using DRM_GEM_SHADOW_PLANE_HELPER_FUNCS and >>>>>>>>>>       DRM_GEM_SHMEM_DRIVER_OPS (e.g., udl, ast) do not require >>>>>>>>>>       sg_table import. >>>>>>>>>>       They only need dma_buf_vmap() to access the shared buffer's >>>>>>>>>>       kernel virtual address. >>>>>>>>>> >>>>>>>>>> 2. On certain Aspeed-based boards, a dma_mask of 0xffff_ffff may >>>>>>>>>>       trigger SWIOTLB during dmabuf import. However, IO_TLB_SEGSIZE >>>>>>>>>>       restricts the maximum DMA streaming mapping memory, resulting in >>>>>>>>>>       errors like: >>>>>>>>>> >>>>>>>>>>       ast 0000:07:00.0: swiotlb buffer is full (sz: 3145728 bytes), total 32768 (slots), used 0 (slots) >>>>>>>>>> >>>>>>>>>> [HOW] >>>>>>>>>> Provide a gem_prime_import implementation without sg_table mapping >>>>>>>>>> to avoid issues (e.g., "swiotlb buffer is full"). Drivers that do not >>>>>>>>>> require sg_table can adopt this. >>>>>>>>>> >>>>>>>>>> Signed-off-by: Shixiong Ou >>>>>>>>>> --- >>>>>>>>>> v1->v2: >>>>>>>>>>       Patch rebase. >>>>>>>>>> v2->v3: >>>>>>>>>>       Rename the import callback function. >>>>>>>>>>       Remove drm_gem_shmem_prime_export() and separate some codes >>>>>>>>>>       to drm_gem_prime_import_self(). >>>>>>>>>> v3->v4: >>>>>>>>>>       Separate the test from the policy. >>>>>>>>>>       Rename the macro. >>>>>>>>>> v4->v5: >>>>>>>>>>       Rename some functions. >>>>>>>>>> >>>>>>>>>>     drivers/gpu/drm/drm_gem_shmem_helper.c | 57 ++++++++++++++++++++++++++ >>>>>>>>>>     drivers/gpu/drm/drm_prime.c            | 36 ++++++++++++---- >>>>>>>>>>     include/drm/drm_gem_shmem_helper.h     | 15 +++++++ >>>>>>>>>>     include/drm/drm_prime.h                |  3 ++ >>>>>>>>>>     4 files changed, 102 insertions(+), 9 deletions(-) >>>>>>>>>> >>>>>>>>>> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c >>>>>>>>>> index aa43265f4f4f..126aa79042ad 100644 >>>>>>>>>> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c >>>>>>>>>> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c >>>>>>>>>> @@ -800,6 +800,63 @@ drm_gem_shmem_prime_import_sg_table(struct drm_device *dev, >>>>>>>>>>     } >>>>>>>>>> EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table); >>>>>>>>>>     +/** >>>>>>>>>> + * drm_gem_shmem_prime_import_no_map - Import dmabuf without mapping its sg_table >>>>>>>>>> + * @dev: Device to import into >>>>>>>>>> + * @dma_buf: dma-buf object to import >>>>>>>>>> + * >>>>>>>>>> + * Drivers that use the shmem helpers but also wants to import dmabuf without >>>>>>>>>> + * mapping its sg_table can use this as their &drm_driver.gem_prime_import >>>>>>>>>> + * implementation. >>>>>>>>>> + */ >>>>>>>>>> +struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev, >>>>>>>>>> +                             struct dma_buf *dma_buf) >>>>>>>>>> +{ >>>>>>>>>> +    struct dma_buf_attachment *attach; >>>>>>>>>> +    struct drm_gem_shmem_object *shmem; >>>>>>>>>> +    struct drm_gem_object *obj; >>>>>>>>>> +    size_t size; >>>>>>>>>> +    int ret; >>>>>>>>>> + >>>>>>>>>> +    if (drm_gem_is_prime_exported_dma_buf(dev, dma_buf)) { >>>>>>>>>> +        /* >>>>>>>>>> +         * Importing dmabuf exported from our own gem increases >>>>>>>>>> +         * refcount on gem itself instead of f_count of dmabuf. >>>>>>>>>> +         */ >>>>>>>>>> +        obj = dma_buf->priv; >>>>>>>>>> +        drm_gem_object_get(obj); >>>>>>>>>> +        return obj; >>>>>>>>>> +    } >>>>>>>>>> + >>>>>>>>>> +    attach = dma_buf_attach(dma_buf, dev->dev); >>>>>>>>>> +    if (IS_ERR(attach)) >>>>>>>>>> +        return ERR_CAST(attach); >>>>>>>>>> + >>>>>>>>>> +    get_dma_buf(dma_buf); >>>>>>>>>> + >>>>>>>>>> +    size = PAGE_ALIGN(attach->dmabuf->size); >>>>>>>>>> + >>>>>>>>>> +    shmem = __drm_gem_shmem_create(dev, size, true, NULL); >>>>>>>>>> +    if (IS_ERR(shmem)) { >>>>>>>>>> +        ret = PTR_ERR(shmem); >>>>>>>>>> +        goto fail_detach; >>>>>>>>>> +    } >>>>>>>>>> + >>>>>>>>>> +    drm_dbg_prime(dev, "size = %zu\n", size); >>>>>>>>>> + >>>>>>>>>> +    shmem->base.import_attach = attach; >>>>>>>>>> +    shmem->base.resv = dma_buf->resv; >>>>>>>>>> + >>>>>>>>>> +    return &shmem->base; >>>>>>>>>> + >>>>>>>>>> +fail_detach: >>>>>>>>>> +    dma_buf_detach(dma_buf, attach); >>>>>>>>>> +    dma_buf_put(dma_buf); >>>>>>>>>> + >>>>>>>>>> +    return ERR_PTR(ret); >>>>>>>>>> +} >>>>>>>>>> +EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_no_map); >>>>>>>>>> + >>>>>>>>>>     MODULE_DESCRIPTION("DRM SHMEM memory-management helpers"); >>>>>>>>>>     MODULE_IMPORT_NS("DMA_BUF"); >>>>>>>>>>     MODULE_LICENSE("GPL v2"); >>>>>>>>>> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c >>>>>>>>>> index d828502268b8..b825b71038d6 100644 >>>>>>>>>> --- a/drivers/gpu/drm/drm_prime.c >>>>>>>>>> +++ b/drivers/gpu/drm/drm_prime.c >>>>>>>>>> @@ -910,6 +910,26 @@ struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj, >>>>>>>>>>     } >>>>>>>>>>     EXPORT_SYMBOL(drm_gem_prime_export); >>>>>>>>>>     + >>>>>>>>>> +/** >>>>>>>>>> + * drm_gem_is_prime_exported_dma_buf - >>>>>>>>>> + * checks if the DMA-BUF was exported from a GEM object belonging to @dev. >>>>>>>>>> + * @dev: drm_device to check against >>>>>>>>>> + * @dma_buf: dma-buf object to import >>>>>>>>>> + * >>>>>>>>>> + * Return: true if the DMA-BUF was exported from a GEM object belonging >>>>>>>>>> + * to @dev, false otherwise. >>>>>>>>>> + */ >>>>>>>>>> + >>>>>>>>>> +bool drm_gem_is_prime_exported_dma_buf(struct drm_device *dev, >>>>>>>>>> +                       struct dma_buf *dma_buf) >>>>>>>>>> +{ >>>>>>>>>> +    struct drm_gem_object *obj = dma_buf->priv; >>>>>>>>>> + >>>>>>>>>> +    return (dma_buf->ops == &drm_gem_prime_dmabuf_ops) && (obj->dev == dev); >>>>>>>>>> +} >>>>>>>>>> +EXPORT_SYMBOL(drm_gem_is_prime_exported_dma_buf); >>>>>>>>>> + >>>>>>>>>>     /** >>>>>>>>>>      * drm_gem_prime_import_dev - core implementation of the import callback >>>>>>>>>>      * @dev: drm_device to import into >>>>>>>>>> @@ -933,16 +953,14 @@ struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev, >>>>>>>>>>         struct drm_gem_object *obj; >>>>>>>>>>         int ret; >>>>>>>>>>     -    if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) { >>>>>>>>>> +    if (drm_gem_is_prime_exported_dma_buf(dev, dma_buf)) { >>>>>>>>>> +        /* >>>>>>>>>> +         * Importing dmabuf exported from our own gem increases >>>>>>>>>> +         * refcount on gem itself instead of f_count of dmabuf. >>>>>>>>>> +         */ >>>>>>>>>>             obj = dma_buf->priv; >>>>>>>>>> -        if (obj->dev == dev) { >>>>>>>>>> -            /* >>>>>>>>>> -             * Importing dmabuf exported from our own gem increases >>>>>>>>>> -             * refcount on gem itself instead of f_count of dmabuf. >>>>>>>>>> -             */ >>>>>>>>>> -            drm_gem_object_get(obj); >>>>>>>>>> -            return obj; >>>>>>>>>> -        } >>>>>>>>>> +        drm_gem_object_get(obj); >>>>>>>>>> +        return obj; >>>>>>>>>>         } >>>>>>>>>>           if (!dev->driver->gem_prime_import_sg_table) >>>>>>>>>> diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h >>>>>>>>>> index b4f993da3cae..35f7466dca84 100644 >>>>>>>>>> --- a/include/drm/drm_gem_shmem_helper.h >>>>>>>>>> +++ b/include/drm/drm_gem_shmem_helper.h >>>>>>>>>> @@ -287,6 +287,8 @@ drm_gem_shmem_prime_import_sg_table(struct drm_device *dev, >>>>>>>>>>                         struct sg_table *sgt); >>>>>>>>>>     int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, >>>>>>>>>>                       struct drm_mode_create_dumb *args); >>>>>>>>>> +struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev, >>>>>>>>>> +                             struct dma_buf *buf); >>>>>>>>>>       /** >>>>>>>>>>      * DRM_GEM_SHMEM_DRIVER_OPS - Default shmem GEM operations >>>>>>>>>> @@ -298,4 +300,17 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, >>>>>>>>>>         .gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table, \ >>>>>>>>>>         .dumb_create           = drm_gem_shmem_dumb_create >>>>>>>>>>     +/** >>>>>>>>>> + * DRM_GEM_SHMEM_DRIVER_OPS_NO_MAP_SGT - shmem GEM operations >>>>>>>>>> + *                                       without mapping sg_table on >>>>>>>>>> + *                                       imported buffer. >>>>>>>>>> + * >>>>>>>>>> + * This macro provides a shortcut for setting the shmem GEM operations in >>>>>>>>>> + * the &drm_driver structure for drivers that do not require a sg_table on >>>>>>>>>> + * imported buffers. >>>>>>>>>> + */ >>>>>>>>>> +#define DRM_GEM_SHMEM_DRIVER_OPS_NO_MAP_SGT \ >>>>>>>>>> +    .gem_prime_import       = drm_gem_shmem_prime_import_no_map, \ >>>>>>>>>> +    .dumb_create            = drm_gem_shmem_dumb_create >>>>>>>>>> + >>>>>>>>>>     #endif /* __DRM_GEM_SHMEM_HELPER_H__ */ >>>>>>>>>> diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h >>>>>>>>>> index fa085c44d4ca..f50f862f0d8b 100644 >>>>>>>>>> --- a/include/drm/drm_prime.h >>>>>>>>>> +++ b/include/drm/drm_prime.h >>>>>>>>>> @@ -100,6 +100,9 @@ struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj, >>>>>>>>>>     unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt); >>>>>>>>>>       /* helper functions for importing */ >>>>>>>>>> +bool drm_gem_is_prime_exported_dma_buf(struct drm_device *dev, >>>>>>>>>> +                       struct dma_buf *dma_buf); >>>>>>>>>> + >>>>>>>>>>     struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev, >>>>>>>>>>                             struct dma_buf *dma_buf, >>>>>>>>>>                             struct device *attach_dev); -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)