Subject: CVE-2024-35927: drm: Check output polling initialized before disabling

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm: Check output polling initialized before disabling

In drm_kms_helper_poll_disable() check if output polling
support is initialized before disabling polling. If not flag
this as a warning.
Additionally in drm_mode_config_helper_suspend() and
drm_mode_config_helper_resume() calls, that re the callers of these
functions, avoid invoking them if polling is not initialized.
For drivers like hyperv-drm, that do not initialize connector
polling, if suspend is called without this check, it leads to
suspend failure with following stack
[  770.719392] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[  770.720592] printk: Suspending console(s) (use no_console_suspend to debug)
[  770.948823] ------------[ cut here ]------------
[  770.948824] WARNING: CPU: 1 PID: 17197 at kernel/workqueue.c:3162 __flush_work.isra.0+0x212/0x230
[  770.948831] Modules linked in: rfkill nft_counter xt_conntrack xt_owner udf nft_compat crc_itu_t nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables nfnetlink vfat fat mlx5_ib ib_uverbs ib_core mlx5_core intel_rapl_msr intel_rapl_common kvm_amd ccp mlxfw kvm psample hyperv_drm tls drm_shmem_helper drm_kms_helper irqbypass pcspkr syscopyarea sysfillrect sysimgblt hv_balloon hv_utils joydev drm fuse xfs libcrc32c pci_hyperv pci_hyperv_intf sr_mod sd_mod cdrom t10_pi sg hv_storvsc scsi_transport_fc hv_netvsc serio_raw hyperv_keyboard hid_hyperv crct10dif_pclmul crc32_pclmul crc32c_intel hv_vmbus ghash_clmulni_intel dm_mirror dm_region_hash dm_log dm_mod
[  770.948863] CPU: 1 PID: 17197 Comm: systemd-sleep Not tainted 5.14.0-362.2.1.el9_3.x86_64 #1
[  770.948865] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 05/09/2022
[  770.948866] RIP: 0010:__flush_work.isra.0+0x212/0x230
[  770.948869] Code: 8b 4d 00 4c 8b 45 08 89 ca 48 c1 e9 04 83 e2 08 83 e1 0f 83 ca 02 89 c8 48 0f ba 6d 00 03 e9 25 ff ff ff 0f 0b e9 4e ff ff ff <0f> 0b 45 31 ed e9 44 ff ff ff e8 8f 89 b2 00 66 66 2e 0f 1f 84 00
[  770.948870] RSP: 0018:ffffaf4ac213fb10 EFLAGS: 00010246
[  770.948871] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8c992857
[  770.948872] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff9aad82b00330
[  770.948873] RBP: ffff9aad82b00330 R08: 0000000000000000 R09: ffff9aad87ee3d10
[  770.948874] R10: 0000000000000200 R11: 0000000000000000 R12: ffff9aad82b00330
[  770.948874] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
[  770.948875] FS:  00007ff1b2f6bb40(0000) GS:ffff9aaf37d00000(0000) knlGS:0000000000000000
[  770.948878] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  770.948878] CR2: 0000555f345cb666 CR3: 00000001462dc005 CR4: 0000000000370ee0
[  770.948879] Call Trace:
[  770.948880]  <TASK>
[  770.948881]  ? show_trace_log_lvl+0x1c4/0x2df
[  770.948884]  ? show_trace_log_lvl+0x1c4/0x2df
[  770.948886]  ? __cancel_work_timer+0x103/0x190
[  770.948887]  ? __flush_work.isra.0+0x212/0x230
[  770.948889]  ? __warn+0x81/0x110
[  770.948891]  ? __flush_work.isra.0+0x212/0x230
[  770.948892]  ? report_bug+0x10a/0x140
[  770.948895]  ? handle_bug+0x3c/0x70
[  770.948898]  ? exc_invalid_op+0x14/0x70
[  770.948899]  ? asm_exc_invalid_op+0x16/0x20
[  770.948903]  ? __flush_work.isra.0+0x212/0x230
[  770.948905]  __cancel_work_timer+0x103/0x190
[  770.948907]  ? _raw_spin_unlock_irqrestore+0xa/0x30
[  770.948910]  drm_kms_helper_poll_disable+0x1e/0x40 [drm_kms_helper]
[  770.948923]  drm_mode_config_helper_suspend+0x1c/0x80 [drm_kms_helper]
[  770.948933]  ? __pfx_vmbus_suspend+0x10/0x10 [hv_vmbus]
[  770.948942]  hyperv_vmbus_suspend+0x17/0x40 [hyperv_drm]
[  770.948944]  ? __pfx_vmbus_suspend+0x10/0x10 [hv_vmbus]
[  770.948951]  dpm_run_callback+0x4c/0x140
[  770.948954]  __device_suspend_noirq+0x74/0x220
[  770.948956]  dpm_noirq_suspend_devices+0x148/0x2a0
[  770.948958]  dpm_suspend_end+0x54/0xe0
[  770.948960]  create_image+0x14/0x290
[  770.948963]  hibernation_snapshot+0xd6/0x200
[  770.948964]  hibernate.cold+0x8b/0x1fb
[  770.948967]  state_store+0xcd/0xd0
[  770.948969]  kernfs_fop_write_iter+0x124/0x1b0
[  770.948973]  new_sync_write+0xff/0x190
[  770.948976]  vfs_write+0x1ef/0x280
[  770.948978]  ksys_write+0x5f/0xe0
[  770.948979]  do_syscall_64+0x5c/0x90
[  770.948981]  ? syscall_exit_work+0x103/0x130
[  770.948983]  ? syscall_exit_to_user_mode+0x12/0x30
[  770.948985]  ? do_syscall_64+0x69/0x90
[  770.948986]  ? do_syscall_64+0x69/0x90
[  770.948987]  ? do_user_addr_fault+0x1d6/0x6a0
[  770.948989]  ? do_syscall_64+0x69/0x90
[  770.948990]  ? exc_page_fault+0x62/0x150
[  770.948992]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
[  770.948995] RIP: 0033:0x7ff1b293eba7
[  770.949010] Code: 0b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[  770.949011] RSP: 002b:00007ffde3912128 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  770.949012] RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007ff1b293eba7
[  770.949013] RDX: 0000000000000005 RSI: 00007ffde3912210 RDI: 0000000000000004
[  770.949014] RBP: 00007ffde3912210 R08: 000055d7dd4c9510 R09: 00007ff1b29b14e0
[  770.949014] R10: 00007ff1b29b13e0 R11: 0000000000000246 R12: 0000000000000005
[  770.949015] R13: 000055d7dd4c53e0 R14: 0000000000000005 R15: 00007ff1b29f69e0
[  770.949016]  </TASK>
[  770.949017] ---[ end trace e6fa0618bfa2f31d ]---

Built-on: Rhel9, Ubuntu22

The Linux kernel CVE team has assigned CVE-2024-35927 to this issue.

Affected and fixed versions
===========================

	Fixed in 5.15.161 with commit 786c27982a39
	Fixed in 6.1.94 with commit 4ad8d57d902f
	Fixed in 6.6.27 with commit 3d1b47e3a935
	Fixed in 6.8.6 with commit 18451798f4a4
	Fixed in 6.9 with commit 5abffb66d12b

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-35927
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/drm_modeset_helper.c
	drivers/gpu/drm/drm_probe_helper.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/786c27982a39d79cc753f84229eb5977ac8ef1c1
	https://git.kernel.org/stable/c/4ad8d57d902fbc7c82507cfc1b031f3a07c3de6e
	https://git.kernel.org/stable/c/3d1b47e3a935abd4f258a945db87e7267ff4079c
	https://git.kernel.org/stable/c/18451798f4a4e7418b9fad7e7dd313fe84b1f545
	https://git.kernel.org/stable/c/5abffb66d12bcac84bf7b66389c571b8bb6e82bd