Re: [PATCH v3,1/2] media: mediatek: vcodec: adding lock to protect decoder context list

[AngeloGioacchino Del Regno]

Il 22/02/24 10:26, Yunfei Dong ha scritto:
> The ctx_list will be deleted when scp getting unexpected behavior, then the
> ctx_list->next will be NULL, the kernel driver maybe access NULL pointer in
> function vpu_dec_ipi_handler when going through each context, then reboot.
>
> Need to add lock to protect the ctx_list to make sure the ctx_list->next isn't
> NULL pointer.
>
> 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
>
> Fixes: 655b86e52eac ("media: mediatek: vcodec: Fix possible invalid memory access for decoder")
> Signed-off-by: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>