⚠️ media: mediatek: vcodec: adding lock to protect decoder context list (Linux Linux)

Description

In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: adding lock to protect decoder context list Add a lock for the ctx_list, to avoid accessing a NULL pointer within the 'vpu_dec_ipi_handler' function when the ctx_list has been deleted due to an unexpected behavior on the SCP IP block. Hardware name: Google juniper sku16 board (DT) pstate: 20400005 (nzCv daif +PAN -UAO -TCO BTYPE=--) pc : vpu_dec_ipi_handler+0x58/0x1f8 [mtk_vcodec_dec] lr : scp_ipi_handler+0xd0/0x194 [mtk_scp] sp : ffffffc0131dbbd0 x29: ffffffc0131dbbd0 x28: 0000000000000000 x27: ffffff9bb277f348 x26: ffffff9bb242ad00 x25: ffffffd2d440d3b8 x24: ffffffd2a13ff1d4 x23: ffffff9bb7fe85a0 x22: ffffffc0133fbdb0 x21: 0000000000000010 x20: ffffff9b050ea328 x19: ffffffc0131dbc08 x18: 0000000000001000 x17: 0000000000000000 x16: ffffffd2d461c6e0 x15: 0000000000000242 x14: 000000000000018f x13: 000000000000004d x12: 0000000000000000 x11: 0000000000000001 x10: fffffffffffffff0 x9 : ffffff9bb6e793a8 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 000000000000003f x5 : 0000000000000040 x4 : fffffffffffffff0 x3 : 0000000000000020 x2 : ffffff9bb6e79080 x1 : 0000000000000010 x0 : ffffffc0131dbc08 Call trace: vpu_dec_ipi_handler+0x58/0x1f8 [mtk_vcodec_dec (HASH:6c3f 2)] scp_ipi_handler+0xd0/0x194 [mtk_scp (HASH:7046 3)] mt8183_scp_irq_handler+0x44/0x88 [mtk_scp (HASH:7046 3)] scp_irq_handler+0x48/0x90 [mtk_scp (HASH:7046 3)] irq_thread_fn+0x38/0x94 irq_thread+0x100/0x1c0 kthread+0x140/0x1fc ret_from_fork+0x10/0x30 Code: 54000088 f94ca50a eb14015f 54000060 (f9400108) ---[ end trace ace43ce36cbd5c93 ]--- Kernel panic - not syncing: Oops: Fatal exception SMP: stopping secondary CPUs Kernel Offset: 0x12c4000000 from 0xffffffc010000000 PHYS_OFFSET: 0xffffffe580000000 CPU features: 0x08240002,2188200c Memory Limit: none