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: [email protected]
> Signed-off-by: Rong Zhang <[email protected]>
> ---
> 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
