From: Mario Limonciello <mario.limonciello@amd.com>
To: "Rong Zhang" <i@rong.moe>,
"Harry Wentland" <harry.wentland@amd.com>,
"Leo Li" <sunpeng.li@amd.com>,
"Rodrigo Siqueira" <siqueira@igalia.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Christian König" <christian.koenig@amd.com>,
"David Airlie" <airlied@gmail.com>,
"Simona Vetter" <simona@ffwll.ch>
Cc: Roman Li <roman.li@amd.com>,
"ChiaHsuan (Tom) Chung" <chiahsuan.chung@amd.com>,
Ray Wu <ray.wu@amd.com>, Wenjing Liu <wenjing.liu@amd.com>,
Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>,
Aurabindo Pillai <aurabindo.pillai@amd.com>,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] drm/amd/display: Fix NULL deref in debugfs odm_combine_segments
Date: Mon, 3 Nov 2025 15:09:44 -0600 [thread overview]
Message-ID: <bea70e02-2d1b-4fc5-bcb0-b1bf33c09139@amd.com> (raw)
In-Reply-To: <7ef252405946f6ab3feff38cc4bd9ddcc49bad56.camel@rong.moe>
On 11/3/2025 12:15 PM, Rong Zhang wrote:
> Hi all,
>
> On Tue, 2025-10-14 at 00:47 +0800, Rong Zhang wrote:
>> When a connector is connected but inactive (e.g., disabled by desktop
>> environments), pipe_ctx->stream_res.tg will be destroyed. Then, reading
>> odm_combine_segments causes kernel NULL pointer dereference.
>>
>> BUG: kernel NULL pointer dereference, address: 0000000000000000
>> #PF: supervisor read access in kernel mode
>> #PF: error_code(0x0000) - not-present page
>> PGD 0 P4D 0
>> Oops: Oops: 0000 [#1] SMP NOPTI
>> CPU: 16 UID: 0 PID: 26474 Comm: cat Not tainted 6.17.0+ #2 PREEMPT(lazy) e6a17af9ee6db7c63e9d90dbe5b28ccab67520c6
>> Hardware name: LENOVO 21Q4/LNVNB161216, BIOS PXCN25WW 03/27/2025
>> RIP: 0010:odm_combine_segments_show+0x93/0xf0 [amdgpu]
>> Code: 41 83 b8 b0 00 00 00 01 75 6e 48 98 ba a1 ff ff ff 48 c1 e0 0c 48 8d 8c 07 d8 02 00 00 48 85 c9 74 2d 48 8b bc 07 f0 08 00 00 <48> 8b 07 48 8b 80 08 02 00>
>> RSP: 0018:ffffd1bf4b953c58 EFLAGS: 00010286
>> RAX: 0000000000005000 RBX: ffff8e35976b02d0 RCX: ffff8e3aeed052d8
>> RDX: 00000000ffffffa1 RSI: ffff8e35a3120800 RDI: 0000000000000000
>> RBP: 0000000000000000 R08: ffff8e3580eb0000 R09: ffff8e35976b02d0
>> R10: ffffd1bf4b953c78 R11: 0000000000000000 R12: ffffd1bf4b953d08
>> R13: 0000000000040000 R14: 0000000000000001 R15: 0000000000000001
>> FS: 00007f44d3f9f740(0000) GS:ffff8e3caa47f000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000000000 CR3: 00000006485c2000 CR4: 0000000000f50ef0
>> PKRU: 55555554
>> Call Trace:
>> <TASK>
>> seq_read_iter+0x125/0x490
>> ? __alloc_frozen_pages_noprof+0x18f/0x350
>> seq_read+0x12c/0x170
>> full_proxy_read+0x51/0x80
>> vfs_read+0xbc/0x390
>> ? __handle_mm_fault+0xa46/0xef0
>> ? do_syscall_64+0x71/0x900
>> ksys_read+0x73/0xf0
>> do_syscall_64+0x71/0x900
>> ? count_memcg_events+0xc2/0x190
>> ? handle_mm_fault+0x1d7/0x2d0
>> ? do_user_addr_fault+0x21a/0x690
>> ? exc_page_fault+0x7e/0x1a0
>> entry_SYSCALL_64_after_hwframe+0x6c/0x74
>> RIP: 0033:0x7f44d4031687
>> Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00>
>> RSP: 002b:00007ffdb4b5f0b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
>> RAX: ffffffffffffffda RBX: 00007f44d3f9f740 RCX: 00007f44d4031687
>> RDX: 0000000000040000 RSI: 00007f44d3f5e000 RDI: 0000000000000003
>> RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000202 R12: 00007f44d3f5e000
>> R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000040000
>> </TASK>
>> Modules linked in: tls tcp_diag inet_diag xt_mark ccm snd_hrtimer snd_seq_dummy snd_seq_midi snd_seq_oss snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device x>
>> snd_hda_codec_atihdmi snd_hda_codec_realtek_lib lenovo_wmi_helpers think_lmi snd_hda_codec_generic snd_hda_codec_hdmi snd_soc_core kvm snd_compress uvcvideo sn>
>> platform_profile joydev amd_pmc mousedev mac_hid sch_fq_codel uinput i2c_dev parport_pc ppdev lp parport nvme_fabrics loop nfnetlink ip_tables x_tables dm_cryp>
>> CR2: 0000000000000000
>> ---[ end trace 0000000000000000 ]---
>> RIP: 0010:odm_combine_segments_show+0x93/0xf0 [amdgpu]
>> Code: 41 83 b8 b0 00 00 00 01 75 6e 48 98 ba a1 ff ff ff 48 c1 e0 0c 48 8d 8c 07 d8 02 00 00 48 85 c9 74 2d 48 8b bc 07 f0 08 00 00 <48> 8b 07 48 8b 80 08 02 00>
>> RSP: 0018:ffffd1bf4b953c58 EFLAGS: 00010286
>> RAX: 0000000000005000 RBX: ffff8e35976b02d0 RCX: ffff8e3aeed052d8
>> RDX: 00000000ffffffa1 RSI: ffff8e35a3120800 RDI: 0000000000000000
>> RBP: 0000000000000000 R08: ffff8e3580eb0000 R09: ffff8e35976b02d0
>> R10: ffffd1bf4b953c78 R11: 0000000000000000 R12: ffffd1bf4b953d08
>> R13: 0000000000040000 R14: 0000000000000001 R15: 0000000000000001
>> FS: 00007f44d3f9f740(0000) GS:ffff8e3caa47f000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000000000 CR3: 00000006485c2000 CR4: 0000000000f50ef0
>> PKRU: 55555554
>>
>> Fix this by checking pipe_ctx->stream_res.tg before dereferencing.
>>
>> Fixes: 07926ba8a44f ("drm/amd/display: Add debugfs interface for ODM combine info")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Rong Zhang <i@rong.moe>
>> ---
>> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>> index f263e1a4537e1..00dac862b665a 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
>> @@ -1302,7 +1302,8 @@ static int odm_combine_segments_show(struct seq_file *m, void *unused)
>> if (connector->status != connector_status_connected)
>> return -ENODEV;
>>
>> - if (pipe_ctx != NULL && pipe_ctx->stream_res.tg->funcs->get_odm_combine_segments)
>> + if (pipe_ctx && pipe_ctx->stream_res.tg &&
>> + pipe_ctx->stream_res.tg->funcs->get_odm_combine_segments)
>> pipe_ctx->stream_res.tg->funcs->get_odm_combine_segments(pipe_ctx->stream_res.tg, &segments);
>>
>> seq_printf(m, "%d\n", segments);
>>
>> base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
>
> Gentle ping.
>
> Thanks,
> Rong
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
And applied, thanks.
prev parent reply other threads:[~2025-11-03 21:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-13 16:47 [PATCH] drm/amd/display: Fix NULL deref in debugfs odm_combine_segments Rong Zhang
2025-11-03 18:15 ` Rong Zhang
2025-11-03 21:09 ` Mario Limonciello [this message]
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