[PATCH 3/3] drm/meson: remove drm bridges at aggregate driver unbind time
Neil Armstrong
neil.armstrong at linaro.org
Mon Sep 19 06:03:14 PDT 2022
On 19/09/2022 03:09, Adrián Larumbe wrote:
> drm bridges added by meson_encoder_hdmi_init and meson_encoder_cvbs_init
> were not manually removed at module unload time, which caused dangling
> references to freed memory to remain linked in the global bridge_list.
>
> When loading the driver modules back in, the same functions would again
> call drm_bridge_add, and when traversing the global bridge_list, would
> end up peeking into freed memory.
>
> Once again KASAN revealed the problem:
>
> [ +0.000095] =============================================================
> [ +0.000008] BUG: KASAN: use-after-free in __list_add_valid+0x9c/0x120
> [ +0.000018] Read of size 8 at addr ffff00003da291f0 by task modprobe/2483
>
> [ +0.000018] CPU: 3 PID: 2483 Comm: modprobe Tainted: G C O 5.19.0-rc6-lrmbkasan+ #1
> [ +0.000011] Hardware name: Hardkernel ODROID-N2Plus (DT)
> [ +0.000008] Call trace:
> [ +0.000006] dump_backtrace+0x1ec/0x280
> [ +0.000012] show_stack+0x24/0x80
> [ +0.000008] dump_stack_lvl+0x98/0xd4
> [ +0.000011] print_address_description.constprop.0+0x80/0x520
> [ +0.000011] print_report+0x128/0x260
> [ +0.000008] kasan_report+0xb8/0xfc
> [ +0.000008] __asan_report_load8_noabort+0x3c/0x50
> [ +0.000009] __list_add_valid+0x9c/0x120
> [ +0.000009] drm_bridge_add+0x6c/0x104 [drm]
> [ +0.000165] dw_hdmi_probe+0x1900/0x2360 [dw_hdmi]
> [ +0.000022] meson_dw_hdmi_bind+0x520/0x814 [meson_dw_hdmi]
> [ +0.000014] component_bind+0x174/0x520
> [ +0.000012] component_bind_all+0x1a8/0x38c
> [ +0.000010] meson_drv_bind_master+0x5e8/0xb74 [meson_drm]
> [ +0.000032] meson_drv_bind+0x20/0x2c [meson_drm]
> [ +0.000027] try_to_bring_up_aggregate_device+0x19c/0x390
> [ +0.000010] component_master_add_with_match+0x1c8/0x284
> [ +0.000009] meson_drv_probe+0x274/0x280 [meson_drm]
> [ +0.000026] platform_probe+0xd0/0x220
> [ +0.000009] really_probe+0x3ac/0xa80
> [ +0.000009] __driver_probe_device+0x1f8/0x400
> [ +0.000009] driver_probe_device+0x68/0x1b0
> [ +0.000009] __driver_attach+0x20c/0x480
> [ +0.000008] bus_for_each_dev+0x114/0x1b0
> [ +0.000009] driver_attach+0x48/0x64
> [ +0.000008] bus_add_driver+0x390/0x564
> [ +0.000009] driver_register+0x1a8/0x3e4
> [ +0.000009] __platform_driver_register+0x6c/0x94
> [ +0.000008] meson_drm_platform_driver_init+0x3c/0x1000 [meson_drm]
> [ +0.000027] do_one_initcall+0xc4/0x2b0
> [ +0.000011] do_init_module+0x154/0x570
> [ +0.000011] load_module+0x1a78/0x1ea4
> [ +0.000008] __do_sys_init_module+0x184/0x1cc
> [ +0.000009] __arm64_sys_init_module+0x78/0xb0
> [ +0.000009] invoke_syscall+0x74/0x260
> [ +0.000009] el0_svc_common.constprop.0+0xcc/0x260
> [ +0.000008] do_el0_svc+0x50/0x70
> [ +0.000007] el0_svc+0x68/0x1a0
> [ +0.000012] el0t_64_sync_handler+0x11c/0x150
> [ +0.000008] el0t_64_sync+0x18c/0x190
>
> [ +0.000016] Allocated by task 879:
> [ +0.000008] kasan_save_stack+0x2c/0x5c
> [ +0.000011] __kasan_kmalloc+0x90/0xd0
> [ +0.000007] __kmalloc+0x278/0x4a0
> [ +0.000011] mpi_resize+0x13c/0x1d0
> [ +0.000011] mpi_powm+0xd24/0x1570
> [ +0.000009] rsa_enc+0x1a4/0x30c
> [ +0.000009] pkcs1pad_verify+0x3f0/0x580
> [ +0.000009] public_key_verify_signature+0x7a8/0xba4
> [ +0.000010] public_key_verify_signature_2+0x40/0x60
> [ +0.000008] verify_signature+0xb4/0x114
> [ +0.000008] pkcs7_validate_trust_one.constprop.0+0x3b8/0x574
> [ +0.000009] pkcs7_validate_trust+0xb8/0x15c
> [ +0.000008] verify_pkcs7_message_sig+0xec/0x1b0
> [ +0.000012] verify_pkcs7_signature+0x78/0xac
> [ +0.000007] mod_verify_sig+0x110/0x190
> [ +0.000009] module_sig_check+0x114/0x1e0
> [ +0.000009] load_module+0xa0/0x1ea4
> [ +0.000008] __do_sys_init_module+0x184/0x1cc
> [ +0.000008] __arm64_sys_init_module+0x78/0xb0
> [ +0.000008] invoke_syscall+0x74/0x260
> [ +0.000009] el0_svc_common.constprop.0+0x1a8/0x260
> [ +0.000008] do_el0_svc+0x50/0x70
> [ +0.000007] el0_svc+0x68/0x1a0
> [ +0.000009] el0t_64_sync_handler+0x11c/0x150
> [ +0.000009] el0t_64_sync+0x18c/0x190
>
> [ +0.000013] Freed by task 2422:
> [ +0.000008] kasan_save_stack+0x2c/0x5c
> [ +0.000009] kasan_set_track+0x2c/0x40
> [ +0.000007] kasan_set_free_info+0x28/0x50
> [ +0.000009] ____kasan_slab_free+0x128/0x1d4
> [ +0.000008] __kasan_slab_free+0x18/0x24
> [ +0.000007] slab_free_freelist_hook+0x108/0x230
> [ +0.000010] kfree+0x110/0x35c
> [ +0.000008] release_nodes+0xf0/0x16c
> [ +0.000009] devres_release_group+0x180/0x270
> [ +0.000008] take_down_aggregate_device+0xcc/0x160
> [ +0.000010] component_del+0x18c/0x360
> [ +0.000009] meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
> [ +0.000013] platform_remove+0x64/0xb0
> [ +0.000008] device_remove+0xb8/0x154
> [ +0.000009] device_release_driver_internal+0x398/0x5b0
> [ +0.000009] driver_detach+0xac/0x1b0
> [ +0.000009] bus_remove_driver+0x158/0x29c
> [ +0.000008] driver_unregister+0x70/0xb0
> [ +0.000009] platform_driver_unregister+0x20/0x2c
> [ +0.000007] meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
> [ +0.000012] __do_sys_delete_module+0x288/0x400
> [ +0.000009] __arm64_sys_delete_module+0x5c/0x80
> [ +0.000009] invoke_syscall+0x74/0x260
> [ +0.000008] el0_svc_common.constprop.0+0xcc/0x260
> [ +0.000008] do_el0_svc+0x50/0x70
> [ +0.000007] el0_svc+0x68/0x1a0
> [ +0.000008] el0t_64_sync_handler+0x11c/0x150
> [ +0.000009] el0t_64_sync+0x18c/0x190
>
> [ +0.000013] The buggy address belongs to the object at ffff00003da29000
> which belongs to the cache kmalloc-1k of size 1024
> [ +0.000008] The buggy address is located 496 bytes inside of
> 1024-byte region [ffff00003da29000, ffff00003da29400)
>
> [ +0.000015] The buggy address belongs to the physical page:
> [ +0.000009] page:fffffc0000f68a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3da28
> [ +0.000012] head:fffffc0000f68a00 order:3 compound_mapcount:0 compound_pincount:0
> [ +0.000009] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff)
> [ +0.000019] raw: 0ffff00000010200 fffffc0000eb5c08 fffffc0000d96608 ffff000000002a80
> [ +0.000008] raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000
> [ +0.000008] page dumped because: kasan: bad access detected
>
> [ +0.000011] Memory state around the buggy address:
> [ +0.000009] ffff00003da29080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ +0.000007] ffff00003da29100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ +0.000007] >ffff00003da29180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ +0.000007] ^
> [ +0.000008] ffff00003da29200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ +0.000006] ffff00003da29280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ +0.000007] ==================================================================
>
> Fix by keeping track of which encoders were initialised in the meson_drm
> structure and manually removing their bridges at aggregate driver's unbind
> time.
>
> Signed-off-by: Adrián Larumbe <adrian.larumbe at collabora.com>
> ---
> drivers/gpu/drm/meson/meson_drv.c | 4 ++++
> drivers/gpu/drm/meson/meson_drv.h | 7 +++++++
> drivers/gpu/drm/meson/meson_encoder_cvbs.c | 7 +++++++
> drivers/gpu/drm/meson/meson_encoder_cvbs.h | 1 +
> drivers/gpu/drm/meson/meson_encoder_hdmi.c | 7 +++++++
> drivers/gpu/drm/meson/meson_encoder_hdmi.h | 1 +
> drivers/gpu/drm/meson/meson_venc.h | 15 +++++++++++++++
> 7 files changed, 42 insertions(+)
>
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index f3da1c214a7c..2b47154b73c2 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -387,6 +387,10 @@ static void meson_drv_unbind(struct device *dev)
> drm_atomic_helper_shutdown(drm);
> free_irq(priv->vsync_irq, drm);
> drm_dev_put(drm);
> +
> + meson_encoder_hdmi_remove(priv);
> + meson_encoder_cvbs_remove(priv);
> +
> component_unbind_all(dev, drm);
>
> if (priv->afbcd.ops)
> diff --git a/drivers/gpu/drm/meson/meson_drv.h b/drivers/gpu/drm/meson/meson_drv.h
> index 177dac3ca3be..2cf279fb4f82 100644
> --- a/drivers/gpu/drm/meson/meson_drv.h
> +++ b/drivers/gpu/drm/meson/meson_drv.h
> @@ -25,6 +25,12 @@ enum vpu_compatible {
> VPU_COMPATIBLE_G12A = 3,
> };
>
> +enum {
> + MESON_ENC_CVBS = 0,
> + MESON_ENC_HDMI,
> + MESON_ENC_LAST,
> +};
> +
> struct meson_drm_match_data {
> enum vpu_compatible compat;
> struct meson_afbcd_ops *afbcd_ops;
> @@ -51,6 +57,7 @@ struct meson_drm {
> struct drm_crtc *crtc;
> struct drm_plane *primary_plane;
> struct drm_plane *overlay_plane;
> + struct drm_encoder *encoders[MESON_ENC_LAST];
>
> const struct meson_drm_soc_limits *limits;
>
> diff --git a/drivers/gpu/drm/meson/meson_encoder_cvbs.c b/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> index 8110a6e39320..00c958b08065 100644
> --- a/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> +++ b/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> @@ -281,5 +281,12 @@ int meson_encoder_cvbs_init(struct meson_drm *priv)
> }
> drm_connector_attach_encoder(connector, &meson_encoder_cvbs->encoder);
>
> + priv->encoders[MESON_ENC_CVBS] = &meson_encoder_cvbs->encoder;
> +
> return 0;
> }
> +
> +void meson_encoder_cvbs_remove(struct meson_drm *priv)
> +{
> + REMOVE_ENCODER_BRIDGES(cvbs, MESON_ENC_CVBS);
> +}
> diff --git a/drivers/gpu/drm/meson/meson_encoder_cvbs.h b/drivers/gpu/drm/meson/meson_encoder_cvbs.h
> index 61d9d183ce7f..09710fec3c66 100644
> --- a/drivers/gpu/drm/meson/meson_encoder_cvbs.h
> +++ b/drivers/gpu/drm/meson/meson_encoder_cvbs.h
> @@ -25,5 +25,6 @@ struct meson_cvbs_mode {
> extern struct meson_cvbs_mode meson_cvbs_modes[MESON_CVBS_MODES_COUNT];
>
> int meson_encoder_cvbs_init(struct meson_drm *priv);
> +void meson_encoder_cvbs_remove(struct meson_drm *priv);
>
> #endif /* __MESON_VENC_CVBS_H */
> diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
> index 2f616c55c271..da6f2882cd97 100644
> --- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
> @@ -452,6 +452,8 @@ int meson_encoder_hdmi_init(struct meson_drm *priv)
> meson_encoder_hdmi->cec_notifier = notifier;
> }
>
> + priv->encoders[MESON_ENC_HDMI] = &meson_encoder_hdmi->encoder;
> +
> dev_dbg(priv->dev, "HDMI encoder initialized\n");
>
> return 0;
> @@ -460,3 +462,8 @@ int meson_encoder_hdmi_init(struct meson_drm *priv)
> of_node_put(remote);
> return ret;
> }
> +
> +void meson_encoder_hdmi_remove(struct meson_drm *priv)
> +{
> + REMOVE_ENCODER_BRIDGES(hdmi, MESON_ENC_HDMI);
> +}
> diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.h b/drivers/gpu/drm/meson/meson_encoder_hdmi.h
> index ed19494f0956..a6cd38eb5f71 100644
> --- a/drivers/gpu/drm/meson/meson_encoder_hdmi.h
> +++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.h
> @@ -8,5 +8,6 @@
> #define __MESON_ENCODER_HDMI_H
>
> int meson_encoder_hdmi_init(struct meson_drm *priv);
> +void meson_encoder_hdmi_remove(struct meson_drm *priv);
>
> #endif /* __MESON_ENCODER_HDMI_H */
> diff --git a/drivers/gpu/drm/meson/meson_venc.h b/drivers/gpu/drm/meson/meson_venc.h
> index 9138255ffc9e..9fc572860f8c 100644
> --- a/drivers/gpu/drm/meson/meson_venc.h
> +++ b/drivers/gpu/drm/meson/meson_venc.h
> @@ -47,6 +47,21 @@ struct meson_cvbs_enci_mode {
> unsigned int analog_sync_adj;
> };
>
> +#define REMOVE_ENCODER_BRIDGES(type, order) \
> +{ \
> + struct meson_encoder_##type *meson_encoder_##type; \
> + struct drm_encoder *encoder; \
> + if (priv->encoders[order]) { \
> + encoder = priv->encoders[order]; \
> + meson_encoder_##type = \
> + container_of(encoder, \
> + struct meson_encoder_##type, \
> + encoder); \
> + drm_bridge_remove(&(meson_encoder_##type)->bridge); \
> + drm_bridge_remove((meson_encoder_##type)->next_bridge); \
> + } \
> +}
This looks over-complicated, why not store the "struct meson_encoder_cvbs/_hdmi" raw pointer in the struct meson_drm encoders table instead ?
With this no need to use container_of and directly call drm_bridge_remove() on bridge & next_bridge.
\
> +
> /* HDMI Clock parameters */
> enum drm_mode_status
> meson_venc_hdmi_supported_mode(const struct drm_display_mode *mode);
Thanks,
Neil
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