Affected: Linux

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_hype…