From: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
To: Maarten Lankhorst <dev@lankhorst.se>, dri-devel@lists.freedesktop.org
Cc: intel-xe@lists.freedesktop.org
Subject: Re: [PATCH 1/1] drm: Fix use-after-free on framebuffers and property blobs when calling drm_dev_unplug
Date: Tue, 10 Mar 2026 15:07:12 +0100 [thread overview]
Message-ID: <e5f73bb2d101390f727a17b288006bc9b5cb2003.camel@linux.intel.com> (raw)
In-Reply-To: <20260225101532.13260-4-dev@lankhorst.se>
On Wed, 2026-02-25 at 11:15 +0100, Maarten Lankhorst wrote:
> When trying to do a rather aggressive test of igt's "xe_module_load
> --r reload" with a full desktop environment and game running I
> noticed
> a few OOPSes when dereferencing freed pointers, related to
> framebuffers and property blobs after the compositor exits.
>
> Solve this by guarding the freeing in drm_file with
> drm_dev_enter/exit,
> and immediately put the references from struct drm_file objects
> during
> drm_dev_unplug().
>
> Related warnings for framebuffers on the subtest:
> [ 739.713076] ------------[ cut here ]------------
> WARN_ON(!list_empty(&dev->mode_config.fb_list))
> [ 739.713079] WARNING: drivers/gpu/drm/drm_mode_config.c:584 at
> drm_mode_config_cleanup+0x30b/0x320 [drm], CPU#12:
> xe_module_load/13145
> [ 739.713172] Modules linked in: rfcomm snd_hrtimer xt_CHECKSUM
> xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp
> xt_addrtype nft_compat x_tables nft_chain_nat nf_nat nf_conntrack
> nf_defrag_ipv6 nf_defrag_ipv4 nf_tables overlay cfg80211 bnep
> mtd_intel_dg snd_hda_codec_intelhdmi mtd snd_hda_codec_hdmi nls_utf8
> mxm_wmi intel_wmi_thunderbolt gigabyte_wmi wmi_bmof xe drm_gpuvm
> drm_gpusvm_helper i2c_algo_bit drm_buddy drm_ttm_helper ttm video
> drm_suballoc_helper gpu_sched drm_client_lib drm_exec
> drm_display_helper cec drm_kunit_helpers drm_kms_helper kunit
> x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_codec_alc882
> snd_hda_codec_realtek_lib snd_hda_codec_generic snd_hda_intel
> snd_soc_avs snd_soc_hda_codec snd_hda_ext_core snd_hda_codec
> snd_hwdep snd_hda_core snd_intel_dspcfg snd_soc_core snd_compress
> ac97_bus snd_pcm snd_seq snd_seq_device snd_timer i2c_i801 i2c_mux
> snd i2c_smbus btusb btrtl btbcm btmtk btintel bluetooth ecdh_generic
> rfkill ecc mei_me mei ioatdma dca wmi nfsd drm i2c_dev fuse nfnetlink
> [ 739.713234] CPU: 12 UID: 0 PID: 13145 Comm: xe_module_load Not
> tainted 7.0.0-rc1-valkyria+ #110 PREEMPT_{RT,(lazy)}
> [ 739.713239] Hardware name: Gigabyte Technology Co., Ltd. X299
> AORUS Gaming 3/X299 AORUS Gaming 3-CF, BIOS F8n 12/06/2021
> [ 739.713241] RIP: 0010:drm_mode_config_cleanup+0x30b/0x320 [drm]
> [ 739.713306] Code: 70 60 48 c7 c7 7a 8d 28 a0 e8 f1 a6 00 00 48 8d
> 7d 88 e8 88 75 fe ff 48 85 c0 75 e2 48 8d 7d 88 e8 1a 75 fe ff e9 a7
> fd ff ff <0f> 0b e9 d6 fe ff ff 0f 0b eb 9c e8 55 0b d2 e1 0f 1f 44
> 00 00 0f
> [ 739.713309] RSP: 0018:ffffc90025003be8 EFLAGS: 00010283
> [ 739.713312] RAX: ffff88814675ba08 RBX: ffff88810d778b40 RCX:
> ffffffff8217ed03
> [ 739.713314] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> ffff88810d778b40
> [ 739.713316] RBP: ffffc90025003c60 R08: 0000000000000001 R09:
> 0000000000000000
> [ 739.713318] R10: 0000000000000000 R11: ffff888141aeaf78 R12:
> ffff88810d778000
> [ 739.713319] R13: ffff88810d778b68 R14: ffff88810d7787d8 R15:
> 000000000000006c
> [ 739.713321] FS: 00007f99dd0e5980(0000) GS:ffff888cec878000(0000)
> knlGS:0000000000000000
> [ 739.713324] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 739.713326] CR2: 00007f9fa46bcac0 CR3: 00000004fe2b2002 CR4:
> 00000000003706f0
> [ 739.713328] Call Trace:
> [ 739.713330] <TASK>
> [ 739.713335] ? intel_pmdemand_destroy_state+0x11/0x20 [xe]
> [ 739.713574] ? intel_atomic_global_obj_cleanup+0xe4/0x1a0 [xe]
> [ 739.713794] intel_display_driver_remove_noirq+0x51/0xb0 [xe]
> [ 739.714041] xe_display_fini_early+0x33/0x50 [xe]
> [ 739.714284] devm_action_release+0xf/0x20
> [ 739.714294] devres_release_all+0xad/0xf0
> [ 739.714301] device_unbind_cleanup+0x12/0xa0
> [ 739.714305] device_release_driver_internal+0x1b7/0x210
> [ 739.714311] device_driver_detach+0x14/0x20
> [ 739.714315] unbind_store+0xa6/0xb0
> [ 739.714319] drv_attr_store+0x21/0x30
> [ 739.714322] sysfs_kf_write+0x48/0x60
> [ 739.714328] kernfs_fop_write_iter+0x16b/0x240
> [ 739.714333] vfs_write+0x266/0x520
> [ 739.714341] ksys_write+0x72/0xe0
> [ 739.714345] __x64_sys_write+0x19/0x20
> [ 739.714347] x64_sys_call+0xa15/0xa30
> [ 739.714355] do_syscall_64+0xd8/0xab0
> [ 739.714361] entry_SYSCALL_64_after_hwframe+0x4b/0x53
> [ 739.714365] RIP: 0033:0x7f99df4aa146
> [ 739.714368] Code: 47 ba 04 00 00 00 48 8b 05 c7 0c 17 00 64 89 10
> 48 c7 c2 ff ff ff ff c9 48 89 d0 c3 0f 1f 84 00 00 00 00 00 48 8b 45
> 10 0f 05 <48> 89 c2 48 3d 00 f0 ff ff 77 0f c9 48 89 d0 c3 66 2e 0f
> 1f 84 00
> [ 739.714371] RSP: 002b:00007fffe4b8fc00 EFLAGS: 00000202 ORIG_RAX:
> 0000000000000001
> [ 739.714374] RAX: ffffffffffffffda RBX: 000000000000000c RCX:
> 00007f99df4aa146
> [ 739.714376] RDX: 000000000000000c RSI: 00005561e56d9073 RDI:
> 0000000000000004
> [ 739.714377] RBP: 00007fffe4b8fc10 R08: 0000000000000000 R09:
> 0000000000000000
> [ 739.714379] R10: 0000000000000000 R11: 0000000000000202 R12:
> 0000000000000004
> [ 739.714380] R13: 0000000000000000 R14: 00005561e56d9073 R15:
> 00005561bb5aacf8
> [ 739.714387] </TASK>
> [ 739.714389] irq event stamp: 0
> [ 739.714390] hardirqs last enabled at (0): [<0000000000000000>]
> 0x0
> [ 739.714392] hardirqs last disabled at (0): [<ffffffff81317d2b>]
> copy_process+0xacb/0x2220
> [ 739.714398] softirqs last enabled at (0): [<ffffffff81317d2b>]
> copy_process+0xacb/0x2220
> [ 739.714401] softirqs last disabled at (0): [<0000000000000000>]
> 0x0
> [ 739.714403] ---[ end trace 0000000000000000 ]---
>
> ....
> [ 739.714459] ------------[ cut here ]------------
> [ 739.714461] xe 0000:67:00.0: [drm] drm_WARN_ON(!list_empty(&fb-
> >filp_head))
> [ 739.714464] WARNING: drivers/gpu/drm/drm_framebuffer.c:833 at
> drm_framebuffer_free+0x6c/0x90 [drm], CPU#12: xe_module_load/13145
> [ 739.714596] Modules linked in: rfcomm snd_hrtimer xt_CHECKSUM
> xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp
> xt_addrtype nft_compat x_tables nft_chain_nat nf_nat nf_conntrack
> nf_defrag_ipv6 nf_defrag_ipv4 nf_tables overlay cfg80211 bnep
> mtd_intel_dg snd_hda_codec_intelhdmi mtd snd_hda_codec_hdmi nls_utf8
> mxm_wmi intel_wmi_thunderbolt gigabyte_wmi wmi_bmof xe drm_gpuvm
> drm_gpusvm_helper i2c_algo_bit drm_buddy drm_ttm_helper ttm video
> drm_suballoc_helper gpu_sched drm_client_lib drm_exec
> drm_display_helper cec drm_kunit_helpers drm_kms_helper kunit
> x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_codec_alc882
> snd_hda_codec_realtek_lib snd_hda_codec_generic snd_hda_intel
> snd_soc_avs snd_soc_hda_codec snd_hda_ext_core snd_hda_codec
> snd_hwdep snd_hda_core snd_intel_dspcfg snd_soc_core snd_compress
> ac97_bus snd_pcm snd_seq snd_seq_device snd_timer i2c_i801 i2c_mux
> snd i2c_smbus btusb btrtl btbcm btmtk btintel bluetooth ecdh_generic
> rfkill ecc mei_me mei ioatdma dca wmi nfsd drm i2c_dev fuse nfnetlink
> [ 739.714704] CPU: 12 UID: 0 PID: 13145 Comm: xe_module_load
> Tainted: G W 7.0.0-rc1-valkyria+ #110
> PREEMPT_{RT,(lazy)}
> [ 739.714711] Tainted: [W]=WARN
> [ 739.714713] Hardware name: Gigabyte Technology Co., Ltd. X299
> AORUS Gaming 3/X299 AORUS Gaming 3-CF, BIOS F8n 12/06/2021
> [ 739.714715] RIP: 0010:drm_framebuffer_free+0x7a/0x90 [drm]
> [ 739.714830] Code: 48 85 d2 75 03 48 8b 17 48 89 55 e0 4c 89 45 e8
> e8 ab 40 74 e1 48 8d 3d b4 5e df ff 48 8b 55 e0 48 c7 c1 30 38 28 a0
> 48 89 c6 <67> 48 0f b9 3a 4c 8b 45 e8 eb 9f 31 ff eb c3 0f 1f 80 00
> 00 00 00
> [ 739.714842] RSP: 0018:ffffc90025003bb8 EFLAGS: 00010282
> [ 739.714846] RAX: ffffffffa0b60f69 RBX: ffff88814675ba28 RCX:
> ffffffffa0283830
> [ 739.714849] RDX: ffff8881033cc9f0 RSI: ffffffffa0b60f69 RDI:
> ffffffffa0235740
> [ 739.714852] RBP: ffffc90025003bd8 R08: ffff88810d778000 R09:
> ffffffffa028815b
> [ 739.714854] R10: 0000000000000000 R11: ffff888141aeaf78 R12:
> ffff88810d778000
> [ 739.714857] R13: ffff888237f18600 R14: ffff88810d7787d8 R15:
> ffffffffa04484f7
> [ 739.714859] FS: 00007f99dd0e5980(0000) GS:ffff888cec878000(0000)
> knlGS:0000000000000000
> [ 739.714863] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 739.714866] CR2: 00007f9fa46bcac0 CR3: 00000004fe2b2002 CR4:
> 00000000003706f0
> [ 739.714869] Call Trace:
> [ 739.714871] <TASK>
> [ 739.714876] drm_mode_config_cleanup+0x26a/0x320 [drm]
> [ 739.714998] ? __drm_printfn_seq_file+0x20/0x20 [drm]
> [ 739.715115] ? drm_mode_config_cleanup+0x207/0x320 [drm]
> [ 739.715235] intel_display_driver_remove_noirq+0x51/0xb0 [xe]
> [ 739.715576] xe_display_fini_early+0x33/0x50 [xe]
> [ 739.715821] devm_action_release+0xf/0x20
> [ 739.715828] devres_release_all+0xad/0xf0
> [ 739.715843] device_unbind_cleanup+0x12/0xa0
> [ 739.715850] device_release_driver_internal+0x1b7/0x210
> [ 739.715856] device_driver_detach+0x14/0x20
> [ 739.715860] unbind_store+0xa6/0xb0
> [ 739.715865] drv_attr_store+0x21/0x30
> [ 739.715868] sysfs_kf_write+0x48/0x60
> [ 739.715873] kernfs_fop_write_iter+0x16b/0x240
> [ 739.715878] vfs_write+0x266/0x520
> [ 739.715886] ksys_write+0x72/0xe0
> [ 739.715890] __x64_sys_write+0x19/0x20
> [ 739.715893] x64_sys_call+0xa15/0xa30
> [ 739.715900] do_syscall_64+0xd8/0xab0
> [ 739.715905] entry_SYSCALL_64_after_hwframe+0x4b/0x53
> [ 739.715908] RIP: 0033:0x7f99df4aa146
> [ 739.715911] Code: 47 ba 04 00 00 00 48 8b 05 c7 0c 17 00 64 89 10
> 48 c7 c2 ff ff ff ff c9 48 89 d0 c3 0f 1f 84 00 00 00 00 00 48 8b 45
> 10 0f 05 <48> 89 c2 48 3d 00 f0 ff ff 77 0f c9 48 89 d0 c3 66 2e 0f
> 1f 84 00
> [ 739.715913] RSP: 002b:00007fffe4b8fc00 EFLAGS: 00000202 ORIG_RAX:
> 0000000000000001
> [ 739.715916] RAX: ffffffffffffffda RBX: 000000000000000c RCX:
> 00007f99df4aa146
> [ 739.715918] RDX: 000000000000000c RSI: 00005561e56d9073 RDI:
> 0000000000000004
> [ 739.715919] RBP: 00007fffe4b8fc10 R08: 0000000000000000 R09:
> 0000000000000000
> [ 739.715921] R10: 0000000000000000 R11: 0000000000000202 R12:
> 0000000000000004
> [ 739.715922] R13: 0000000000000000 R14: 00005561e56d9073 R15:
> 00005561bb5aacf8
> [ 739.715929] </TASK>
> [ 739.715930] irq event stamp: 0
> [ 739.715931] hardirqs last enabled at (0): [<0000000000000000>]
> 0x0
> [ 739.715933] hardirqs last disabled at (0): [<ffffffff81317d2b>]
> copy_process+0xacb/0x2220
> [ 739.715938] softirqs last enabled at (0): [<ffffffff81317d2b>]
> copy_process+0xacb/0x2220
> [ 739.715941] softirqs last disabled at (0): [<0000000000000000>]
> 0x0
> [ 739.715943] ---[ end trace 0000000000000000 ]---
>
> ...
>
> [ 743.186530] Oops: general protection fault, probably for non-
> canonical address 0xdead000000000122: 0000 [#1] SMP
> [ 743.186535] CPU: 3 UID: 1000 PID: 3453 Comm: kwin_wayland Tainted:
> G W 7.0.0-rc1-valkyria+ #110 PREEMPT_{RT,(lazy)}
> [ 743.186537] Tainted: [W]=WARN
> [ 743.186538] Hardware name: Gigabyte Technology Co., Ltd. X299
> AORUS Gaming 3/X299 AORUS Gaming 3-CF, BIOS F8n 12/06/2021
> [ 743.186539] RIP: 0010:drm_framebuffer_cleanup+0x55/0xc0 [drm]
> [ 743.186588] Code: d8 72 73 0f b6 42 05 ff c3 39 c3 72 e8 49 8d bd
> 50 07 00 00 31 f6 e8 3a 80 d3 e1 49 8b 44 24 10 49 8d 7c 24 08 49 8b
> 54 24 08 <48> 3b 38 0f 85 95 7f 02 00 48 3b 7a 08 0f 85 8b 7f 02 00
> 48 89 42
> [ 743.186589] RSP: 0018:ffffc900085e3cf8 EFLAGS: 00010202
> [ 743.186591] RAX: dead000000000122 RBX: 0000000000000001 RCX:
> ffffffff8217ed03
> [ 743.186592] RDX: dead000000000100 RSI: 0000000000000000 RDI:
> ffff88814675ba08
> [ 743.186593] RBP: ffffc900085e3d10 R08: 0000000000000000 R09:
> 0000000000000000
> [ 743.186593] R10: 0000000000000000 R11: 0000000000000000 R12:
> ffff88814675ba00
> [ 743.186594] R13: ffff88810d778000 R14: ffff888119f6dca0 R15:
> ffff88810c660bb0
> [ 743.186595] FS: 00007ff377d21280(0000) GS:ffff888cec3f8000(0000)
> knlGS:0000000000000000
> [ 743.186596] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 743.186596] CR2: 000055690b55e000 CR3: 0000000113586003 CR4:
> 00000000003706f0
> [ 743.186597] Call Trace:
> [ 743.186598] <TASK>
> [ 743.186603] intel_user_framebuffer_destroy+0x12/0x90 [xe]
> [ 743.186722] drm_framebuffer_free+0x3a/0x90 [drm]
> [ 743.186750] ? trace_hardirqs_on+0x5f/0x120
> [ 743.186754] drm_mode_object_put+0x51/0x70 [drm]
> [ 743.186786] drm_fb_release+0x105/0x190 [drm]
> [ 743.186812] ? rt_mutex_slowunlock+0x3aa/0x410
> [ 743.186817] ? rt_spin_lock+0xea/0x1b0
> [ 743.186819] drm_file_free+0x1e0/0x2c0 [drm]
> [ 743.186843] drm_release_noglobal+0x91/0xf0 [drm]
> [ 743.186865] __fput+0x100/0x2e0
> [ 743.186869] fput_close_sync+0x40/0xa0
> [ 743.186870] __x64_sys_close+0x3e/0x80
> [ 743.186873] x64_sys_call+0xa07/0xa30
> [ 743.186879] do_syscall_64+0xd8/0xab0
> [ 743.186881] entry_SYSCALL_64_after_hwframe+0x4b/0x53
> [ 743.186882] RIP: 0033:0x7ff37e567732
> [ 743.186884] Code: 08 0f 85 a1 38 ff ff 49 89 fb 48 89 f0 48 89 d7
> 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24
> 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 55
> bf 01 00
> [ 743.186885] RSP: 002b:00007ffc818169a8 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000003
> [ 743.186886] RAX: ffffffffffffffda RBX: 00007ffc81816a30 RCX:
> 00007ff37e567732
> [ 743.186887] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> 0000000000000012
> [ 743.186888] RBP: 00007ffc818169d0 R08: 0000000000000000 R09:
> 0000000000000000
> [ 743.186889] R10: 0000000000000000 R11: 0000000000000246 R12:
> 000055d60a7996e0
> [ 743.186889] R13: 00007ffc81816a90 R14: 00007ffc81816a90 R15:
> 000055d60a782a30
> [ 743.186892] </TASK>
> [ 743.186893] Modules linked in: rfcomm snd_hrtimer xt_CHECKSUM
> xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp
> xt_addrtype nft_compat x_tables nft_chain_nat nf_nat nf_conntrack
> nf_defrag_ipv6 nf_defrag_ipv4 nf_tables overlay cfg80211 bnep
> mtd_intel_dg snd_hda_codec_intelhdmi mtd snd_hda_codec_hdmi nls_utf8
> mxm_wmi intel_wmi_thunderbolt gigabyte_wmi wmi_bmof xe drm_gpuvm
> drm_gpusvm_helper i2c_algo_bit drm_buddy drm_ttm_helper ttm video
> drm_suballoc_helper gpu_sched drm_client_lib drm_exec
> drm_display_helper cec drm_kunit_helpers drm_kms_helper kunit
> x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_codec_alc882
> snd_hda_codec_realtek_lib snd_hda_codec_generic snd_hda_intel
> snd_soc_avs snd_soc_hda_codec snd_hda_ext_core snd_hda_codec
> snd_hwdep snd_hda_core snd_intel_dspcfg snd_soc_core snd_compress
> ac97_bus snd_pcm snd_seq snd_seq_device snd_timer i2c_i801 i2c_mux
> snd i2c_smbus btusb btrtl btbcm btmtk btintel bluetooth ecdh_generic
> rfkill ecc mei_me mei ioatdma dca wmi nfsd drm i2c_dev fuse nfnetlink
> [ 743.186938] ---[ end trace 0000000000000000 ]---
>
> And for property blobs:
>
> void drm_mode_config_cleanup(struct drm_device *dev)
> {
> ...
> list_for_each_entry_safe(blob, bt, &dev-
> >mode_config.property_blob_list,
> head_global) {
> drm_property_blob_put(blob);
> }
>
> Resulting in:
>
> [ 371.072940] BUG: unable to handle page fault for address:
> 000001ffffffffff
> [ 371.072944] #PF: supervisor read access in kernel mode
> [ 371.072945] #PF: error_code(0x0000) - not-present page
> [ 371.072947] PGD 0 P4D 0
> [ 371.072950] Oops: Oops: 0000 [#1] SMP
> [ 371.072953] CPU: 0 UID: 1000 PID: 3693 Comm: kwin_wayland Not
> tainted 7.0.0-rc1-valkyria+ #111 PREEMPT_{RT,(lazy)}
> [ 371.072956] Hardware name: Gigabyte Technology Co., Ltd. X299
> AORUS Gaming 3/X299 AORUS Gaming 3-CF, BIOS F8n 12/06/2021
> [ 371.072957] RIP: 0010:drm_property_destroy_user_blobs+0x3b/0x90
> [drm]
> [ 371.073019] Code: 00 00 48 83 ec 10 48 8b 86 30 01 00 00 48 39 c3
> 74 59 48 89 c2 48 8d 48 c8 48 8b 00 4c 8d 60 c8 eb 04 4c 8d 60 c8 48
> 8b 71 40 <48> 39 16 0f 85 39 32 01 00 48 3b 50 08 0f 85 2f 32 01 00
> 48 89 70
> [ 371.073021] RSP: 0018:ffffc90006a73de8 EFLAGS: 00010293
> [ 371.073022] RAX: 000001ffffffffff RBX: ffff888118a1a930 RCX:
> ffff8881b92355c0
> [ 371.073024] RDX: ffff8881b92355f8 RSI: 000001ffffffffff RDI:
> ffff888118be4000
> [ 371.073025] RBP: ffffc90006a73e08 R08: ffff8881009b7300 R09:
> ffff888cecc5b000
> [ 371.073026] R10: ffffc90006a73e90 R11: 0000000000000002 R12:
> 000001ffffffffc7
> [ 371.073027] R13: ffff888118a1a980 R14: ffff88810b366d20 R15:
> ffff888118a1a970
> [ 371.073028] FS: 00007f1faccbb280(0000) GS:ffff888cec2db000(0000)
> knlGS:0000000000000000
> [ 371.073029] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 371.073030] CR2: 000001ffffffffff CR3: 000000010655c001 CR4:
> 00000000003706f0
> [ 371.073031] Call Trace:
> [ 371.073033] <TASK>
> [ 371.073036] drm_file_free+0x1df/0x2a0 [drm]
> [ 371.073077] drm_release_noglobal+0x7a/0xe0 [drm]
> [ 371.073113] __fput+0xe2/0x2b0
> [ 371.073118] fput_close_sync+0x40/0xa0
> [ 371.073119] __x64_sys_close+0x3e/0x80
> [ 371.073122] x64_sys_call+0xa07/0xa30
> [ 371.073126] do_syscall_64+0xc0/0x840
> [ 371.073130] entry_SYSCALL_64_after_hwframe+0x4b/0x53
> [ 371.073132] RIP: 0033:0x7f1fb3501732
> [ 371.073133] Code: 08 0f 85 a1 38 ff ff 49 89 fb 48 89 f0 48 89 d7
> 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24
> 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 55
> bf 01 00
> [ 371.073135] RSP: 002b:00007ffe8e6f0278 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000003
> [ 371.073136] RAX: ffffffffffffffda RBX: 00007ffe8e6f0300 RCX:
> 00007f1fb3501732
> [ 371.073137] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> 0000000000000012
> [ 371.073138] RBP: 00007ffe8e6f02a0 R08: 0000000000000000 R09:
> 0000000000000000
> [ 371.073139] R10: 0000000000000000 R11: 0000000000000246 R12:
> 00005585ba46eea0
> [ 371.073140] R13: 00007ffe8e6f0360 R14: 00007ffe8e6f0360 R15:
> 00005585ba458a30
> [ 371.073143] </TASK>
> [ 371.073144] Modules linked in: rfcomm snd_hrtimer xt_addrtype
> xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4
> xt_tcpudp nft_compat x_tables nft_chain_nat nf_nat nf_conntrack
> nf_defrag_ipv6 nf_defrag_ipv4 nf_tables overlay cfg80211 bnep
> snd_hda_codec_intelhdmi snd_hda_codec_hdmi mtd_intel_dg mtd nls_utf8
> wmi_bmof mxm_wmi gigabyte_wmi intel_wmi_thunderbolt xe drm_gpuvm
> drm_gpusvm_helper i2c_algo_bit drm_buddy drm_ttm_helper ttm video
> drm_suballoc_helper gpu_sched drm_client_lib drm_exec
> drm_display_helper cec drm_kunit_helpers drm_kms_helper kunit
> x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_codec_alc882
> snd_hda_codec_realtek_lib snd_hda_codec_generic snd_hda_intel
> snd_soc_avs snd_soc_hda_codec snd_hda_ext_core snd_hda_codec
> snd_hwdep snd_hda_core snd_intel_dspcfg snd_soc_core snd_compress
> ac97_bus snd_pcm snd_seq snd_seq_device snd_timer i2c_i801 btusb
> i2c_mux i2c_smbus btrtl snd btbcm btmtk btintel bluetooth
> ecdh_generic rfkill ecc mei_me mei ioatdma dca wmi nfsd drm i2c_dev
> fuse nfnetlink
> [ 371.073198] CR2: 000001ffffffffff
> [ 371.073199] ---[ end trace 0000000000000000 ]---
>
> Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
> ---
> drivers/gpu/drm/drm_crtc_internal.h | 4 +++-
> drivers/gpu/drm/drm_drv.c | 3 +++
> drivers/gpu/drm/drm_file.c | 5 ++++-
> drivers/gpu/drm/drm_framebuffer.c | 25 +++++++++++++++++++++++++
> drivers/gpu/drm/drm_mode_config.c | 8 ++++++++
> drivers/gpu/drm/drm_property.c | 20 ++++++++++++++++++++
> 6 files changed, 63 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_crtc_internal.h
> b/drivers/gpu/drm/drm_crtc_internal.h
> index c094092296448..56834596a496f 100644
> --- a/drivers/gpu/drm/drm_crtc_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_internal.h
> @@ -94,6 +94,7 @@ int drm_mode_setcrtc(struct drm_device *dev,
>
> /* drm_mode_config.c */
> int drm_modeset_register_all(struct drm_device *dev);
> +void drm_modeset_unplug_all(struct drm_device *dev);
> void drm_modeset_unregister_all(struct drm_device *dev);
> void drm_mode_config_validate(struct drm_device *dev);
>
> @@ -133,6 +134,7 @@ int drm_mode_gamma_set_ioctl(struct drm_device
> *dev,
> /* drm_property.c */
> void drm_property_destroy_user_blobs(struct drm_device *dev,
> struct drm_file *file_priv);
> +void drm_property_blob_unplug(struct drm_device *dev);
> bool drm_property_change_valid_get(struct drm_property *property,
> uint64_t value,
> struct drm_mode_object **ref);
> @@ -221,7 +223,7 @@ int drm_mode_addfb2(struct drm_device *dev,
> void *data, struct drm_file *file_priv);
> int drm_mode_rmfb(struct drm_device *dev, u32 fb_id,
> struct drm_file *file_priv);
> -
> +void drm_framebuffer_unplug(struct drm_device *dev);
>
> /* IOCTL */
> int drm_mode_addfb_ioctl(struct drm_device *dev,
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 2915118436ce8..36276ed0b74f4 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -493,6 +493,9 @@ void drm_dev_unplug(struct drm_device *dev)
> dev->unplugged = true;
> synchronize_srcu(&drm_unplug_srcu);
>
> + if (drm_core_check_feature(dev, DRIVER_MODESET))
> + drm_modeset_unplug_all(dev);
> +
I'm not 100% familiar with the modesetting code, but couldn't we be
calling drm_mode_config_cleanup() as a drmm-managed cleanup? That would
then be happening after the unplug, but perhaps it ends up using the
wrong order?
Continuing to review as if that doesn't work.
> drm_dev_unregister(dev);
>
> /* Clear all CPU mappings pointing to this device */
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index ec820686b3021..f52141f842a1f 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -233,6 +233,7 @@ static void drm_events_release(struct drm_file
> *file_priv)
> void drm_file_free(struct drm_file *file)
> {
> struct drm_device *dev;
> + int idx;
>
> if (!file)
> return;
> @@ -249,9 +250,11 @@ void drm_file_free(struct drm_file *file)
>
> drm_events_release(file);
>
> - if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> + if (drm_core_check_feature(dev, DRIVER_MODESET) &&
> + drm_dev_enter(dev, &idx)) {
> drm_fb_release(file);
> drm_property_destroy_user_blobs(dev, file);
> + drm_dev_exit(idx);
> }
>
> if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
> diff --git a/drivers/gpu/drm/drm_framebuffer.c
> b/drivers/gpu/drm/drm_framebuffer.c
> index 147ac19f851b2..8325bf59a5eb0 100644
> --- a/drivers/gpu/drm/drm_framebuffer.c
> +++ b/drivers/gpu/drm/drm_framebuffer.c
> @@ -1236,3 +1236,28 @@ void drm_framebuffer_debugfs_init(struct
> drm_device *dev)
>
> ARRAY_SIZE(drm_framebuffer_debugfs_list));
> }
> #endif
> +
> +/**
> + * drm_framebuffer_unplug - unplug fb from file list
> + * @dev: drm device
> + *
> + * This function is called from drm_dev_unplug() and removes all
> + * the references to framebuffers from any &struct drm_file that
> + * had opened one.
> + *
> + * This prevents a use-after-free when closing &struct drm_file.
> + *
> + * There is no need to call drm_framebuffer_remove, as the driver
> + * is now gone and will perform it's own cleanup of framebuffers.
> + */
> +void drm_framebuffer_unplug(struct drm_device *dev)
> +{
> + struct drm_framebuffer *fb, *next;
> +
> + list_for_each_entry_safe(fb, next, &dev-
> >mode_config.fb_list, head) {
> + if (!list_empty(&fb->filp_head)) {
> + list_del_init(&fb->filp_head);
> + drm_framebuffer_put(fb);
> + }
> + }
> +}
I think this needs to be related in the docs to
drm_mode_config_cleanup(). Also document in the same way why locking is
not needed.
> diff --git a/drivers/gpu/drm/drm_mode_config.c
> b/drivers/gpu/drm/drm_mode_config.c
> index 84ae8a23a3678..afe5a55276ee6 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -68,6 +68,14 @@ int drm_modeset_register_all(struct drm_device
> *dev)
> return ret;
> }
>
> +void drm_modeset_unplug_all(struct drm_device *dev)
Kerneldoc
> +{
> + /* With drm_dev_enter() now failing, it's safe to unplug all
> file_priv->fb's and user mode blobs */
> + drm_framebuffer_unplug(dev);
> + drm_property_blob_unplug(dev);
> +
> +}
> +
> void drm_modeset_unregister_all(struct drm_device *dev)
> {
> drm_connector_unregister_all(dev);
> diff --git a/drivers/gpu/drm/drm_property.c
> b/drivers/gpu/drm/drm_property.c
> index f38f2c5437e68..76ff53ed28917 100644
> --- a/drivers/gpu/drm/drm_property.c
> +++ b/drivers/gpu/drm/drm_property.c
> @@ -1008,3 +1008,23 @@ void drm_property_change_valid_put(struct
> drm_property *property,
> } else if (drm_property_type_is(property,
> DRM_MODE_PROP_BLOB))
> drm_property_blob_put(obj_to_blob(ref));
> }
> +
> +/**
> + * drm_property_blob_unplug - remove all &struct drm_file references
> to blobs
> + * @dev: drm device
> + *
> + * This function is called during drm_dev_unplug(), and is intended
> to remove all
> + * references to property blobs held by all files, so they are not
> freed at
> + * file exit, but sooner.
> + */
Same comment as for framebuffers.
Thanks,
Thomas
> +void drm_property_blob_unplug(struct drm_device *dev)
> +{
> + struct drm_property_blob *blob, *next;
> +
> + list_for_each_entry_safe(blob, next, &dev-
> >mode_config.property_blob_list, head_global) {
> + if (!list_empty(&blob->head_file)) {
> + list_del_init(&blob->head_file);
> + drm_property_blob_put(blob);
> + }
> + }
> +}
next prev parent reply other threads:[~2026-03-10 14:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 10:15 [PATCH 0/1] Fix use-after-free on framebuffers and property blobs when calling drm_dev_unplug Maarten Lankhorst
2026-02-25 10:15 ` [PATCH 1/1] drm: " Maarten Lankhorst
2026-03-10 14:07 ` Thomas Hellström [this message]
2026-02-25 10:20 ` ✗ CI.checkpatch: warning for " Patchwork
2026-02-25 10:22 ` ✓ CI.KUnit: success " Patchwork
2026-02-25 11:09 ` ✓ Xe.CI.BAT: " Patchwork
2026-02-25 15:51 ` ✓ Xe.CI.FULL: " Patchwork
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