| Message ID | 20220919010940.419893-2-adrian.larumbe@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/meson: fix use-after-free driver unload issues | expand |
On 19/09/2022 03:09, Adrián Larumbe wrote: > Unloading the driver triggers the following KASAN warning: > > [ +0.006275] ============================================================= > [ +0.000029] BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0x1a0 > [ +0.000026] Read of size 8 at addr ffff000020c395e0 by task rmmod/2695 > > [ +0.000019] CPU: 5 PID: 2695 Comm: rmmod Tainted: G C O 5.19.0-rc6-lrmbkasan+ #1 > [ +0.000013] Hardware name: Hardkernel ODROID-N2Plus (DT) > [ +0.000008] Call trace: > [ +0.000007] dump_backtrace+0x1ec/0x280 > [ +0.000013] 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 > [ +0.000007] kasan_report+0xb8/0xfc > [ +0.000008] __asan_report_load8_noabort+0x3c/0x50 > [ +0.000010] __list_del_entry_valid+0xe0/0x1a0 > [ +0.000009] drm_atomic_private_obj_fini+0x30/0x200 [drm] > [ +0.000172] drm_bridge_detach+0x94/0x260 [drm] > [ +0.000145] drm_encoder_cleanup+0xa4/0x290 [drm] > [ +0.000144] drm_mode_config_cleanup+0x118/0x740 [drm] > [ +0.000143] drm_mode_config_init_release+0x1c/0x2c [drm] > [ +0.000144] drm_managed_release+0x170/0x414 [drm] > [ +0.000142] drm_dev_put.part.0+0xc0/0x124 [drm] > [ +0.000143] drm_dev_put+0x20/0x30 [drm] > [ +0.000142] meson_drv_unbind+0x1d8/0x2ac [meson_drm] > [ +0.000028] take_down_aggregate_device+0xb0/0x160 > [ +0.000016] component_del+0x18c/0x360 > [ +0.000009] meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi] > [ +0.000015] platform_remove+0x64/0xb0 > [ +0.000009] 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 > [ +0.000009] driver_unregister+0x70/0xb0 > [ +0.000008] platform_driver_unregister+0x20/0x2c > [ +0.000008] meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi] > [ +0.000012] __do_sys_delete_module+0x288/0x400 > [ +0.000011] __arm64_sys_delete_module+0x5c/0x80 > [ +0.000009] invoke_syscall+0x74/0x260 > [ +0.000009] el0_svc_common.constprop.0+0xcc/0x260 > [ +0.000009] 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 > > [ +0.000018] Allocated by task 0: > [ +0.000007] (stack is not available) > > [ +0.000011] Freed by task 2695: > [ +0.000008] kasan_save_stack+0x2c/0x5c > [ +0.000011] kasan_set_track+0x2c/0x40 > [ +0.000008] 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 > [ +0.000011] kfree+0x110/0x35c > [ +0.000008] release_nodes+0xf0/0x16c > [ +0.000009] devres_release_group+0x180/0x270 > [ +0.000008] component_unbind+0x128/0x1e0 > [ +0.000010] component_unbind_all+0x1b8/0x264 > [ +0.000009] meson_drv_unbind+0x1a0/0x2ac [meson_drm] > [ +0.000025] take_down_aggregate_device+0xb0/0x160 > [ +0.000009] component_del+0x18c/0x360 > [ +0.000009] meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi] > [ +0.000012] 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 > [ +0.000008] platform_driver_unregister+0x20/0x2c > [ +0.000008] meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi] > [ +0.000011] __do_sys_delete_module+0x288/0x400 > [ +0.000010] __arm64_sys_delete_module+0x5c/0x80 > [ +0.000008] 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 > [ +0.000009] el0t_64_sync_handler+0x11c/0x150 > [ +0.000009] el0t_64_sync+0x18c/0x190 > > [ +0.000014] The buggy address belongs to the object at ffff000020c39000 > which belongs to the cache kmalloc-4k of size 4096 > [ +0.000008] The buggy address is located 1504 bytes inside of > 4096-byte region [ffff000020c39000, ffff000020c3a000) > > [ +0.000016] The buggy address belongs to the physical page: > [ +0.000009] page:fffffc0000830e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20c38 > [ +0.000013] head:fffffc0000830e00 order:3 compound_mapcount:0 compound_pincount:0 > [ +0.000008] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff) > [ +0.000019] raw: 0ffff00000010200 fffffc0000fd4808 fffffc0000126208 ffff000000002e80 > [ +0.000009] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 > [ +0.000008] page dumped because: kasan: bad access detected > > [ +0.000011] Memory state around the buggy address: > [ +0.000008] ffff000020c39480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > [ +0.000007] ffff000020c39500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > [ +0.000007] >ffff000020c39580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > [ +0.000007] ^ > [ +0.000007] ffff000020c39600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > [ +0.000007] ffff000020c39680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > [ +0.000006] ================================================================== > > The reason this is happening is unloading meson-dw-hdmi will cause the > component API to take down the aggregate device, which in turn will cause > all devres-managed memory to be freed, including the struct dw_hdmi > allocated in dw_hdmi_probe. This struct embeds a struct drm_bridge that is > added at the end of the function, and which is later on picked up in > meson_encoder_hdmi_init. > > However, when attaching the bridge to the encoder created in > meson_encoder_hdmi_init, it's linked to the encoder's bridge chain, from > where it never leaves, even after devres_release_group is called when the > driver's components are unbound and the embedding structure freed. > > Then, when calling drm_dev_put in the aggregate driver's unbind function, > drm_bridge_detach is called for every single bridge linked to the encoder, > including the one whose memory had already been deallocated. > > Fix by calling component_unbind_all after drm_dev_put. > > Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com> > --- > drivers/gpu/drm/meson/meson_drv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c > index ef386d7b9450..8da454a17b77 100644 > --- a/drivers/gpu/drm/meson/meson_drv.c > +++ b/drivers/gpu/drm/meson/meson_drv.c > @@ -385,9 +385,9 @@ static void meson_drv_unbind(struct device *dev) > drm_dev_unregister(drm); > drm_kms_helper_poll_fini(drm); > drm_atomic_helper_shutdown(drm); > - component_unbind_all(dev, drm); > free_irq(priv->vsync_irq, drm); > drm_dev_put(drm); > + component_unbind_all(dev, drm); > > if (priv->afbcd.ops) > priv->afbcd.ops->exit(priv); Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c index ef386d7b9450..8da454a17b77 100644 --- a/drivers/gpu/drm/meson/meson_drv.c +++ b/drivers/gpu/drm/meson/meson_drv.c @@ -385,9 +385,9 @@ static void meson_drv_unbind(struct device *dev) drm_dev_unregister(drm); drm_kms_helper_poll_fini(drm); drm_atomic_helper_shutdown(drm); - component_unbind_all(dev, drm); free_irq(priv->vsync_irq, drm); drm_dev_put(drm); + component_unbind_all(dev, drm); if (priv->afbcd.ops) priv->afbcd.ops->exit(priv);
Unloading the driver triggers the following KASAN warning: [ +0.006275] ============================================================= [ +0.000029] BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0x1a0 [ +0.000026] Read of size 8 at addr ffff000020c395e0 by task rmmod/2695 [ +0.000019] CPU: 5 PID: 2695 Comm: rmmod Tainted: G C O 5.19.0-rc6-lrmbkasan+ #1 [ +0.000013] Hardware name: Hardkernel ODROID-N2Plus (DT) [ +0.000008] Call trace: [ +0.000007] dump_backtrace+0x1ec/0x280 [ +0.000013] 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 [ +0.000007] kasan_report+0xb8/0xfc [ +0.000008] __asan_report_load8_noabort+0x3c/0x50 [ +0.000010] __list_del_entry_valid+0xe0/0x1a0 [ +0.000009] drm_atomic_private_obj_fini+0x30/0x200 [drm] [ +0.000172] drm_bridge_detach+0x94/0x260 [drm] [ +0.000145] drm_encoder_cleanup+0xa4/0x290 [drm] [ +0.000144] drm_mode_config_cleanup+0x118/0x740 [drm] [ +0.000143] drm_mode_config_init_release+0x1c/0x2c [drm] [ +0.000144] drm_managed_release+0x170/0x414 [drm] [ +0.000142] drm_dev_put.part.0+0xc0/0x124 [drm] [ +0.000143] drm_dev_put+0x20/0x30 [drm] [ +0.000142] meson_drv_unbind+0x1d8/0x2ac [meson_drm] [ +0.000028] take_down_aggregate_device+0xb0/0x160 [ +0.000016] component_del+0x18c/0x360 [ +0.000009] meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi] [ +0.000015] platform_remove+0x64/0xb0 [ +0.000009] 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 [ +0.000009] driver_unregister+0x70/0xb0 [ +0.000008] platform_driver_unregister+0x20/0x2c [ +0.000008] meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi] [ +0.000012] __do_sys_delete_module+0x288/0x400 [ +0.000011] __arm64_sys_delete_module+0x5c/0x80 [ +0.000009] invoke_syscall+0x74/0x260 [ +0.000009] el0_svc_common.constprop.0+0xcc/0x260 [ +0.000009] 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 [ +0.000018] Allocated by task 0: [ +0.000007] (stack is not available) [ +0.000011] Freed by task 2695: [ +0.000008] kasan_save_stack+0x2c/0x5c [ +0.000011] kasan_set_track+0x2c/0x40 [ +0.000008] 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 [ +0.000011] kfree+0x110/0x35c [ +0.000008] release_nodes+0xf0/0x16c [ +0.000009] devres_release_group+0x180/0x270 [ +0.000008] component_unbind+0x128/0x1e0 [ +0.000010] component_unbind_all+0x1b8/0x264 [ +0.000009] meson_drv_unbind+0x1a0/0x2ac [meson_drm] [ +0.000025] take_down_aggregate_device+0xb0/0x160 [ +0.000009] component_del+0x18c/0x360 [ +0.000009] meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi] [ +0.000012] 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 [ +0.000008] platform_driver_unregister+0x20/0x2c [ +0.000008] meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi] [ +0.000011] __do_sys_delete_module+0x288/0x400 [ +0.000010] __arm64_sys_delete_module+0x5c/0x80 [ +0.000008] 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 [ +0.000009] el0t_64_sync_handler+0x11c/0x150 [ +0.000009] el0t_64_sync+0x18c/0x190 [ +0.000014] The buggy address belongs to the object at ffff000020c39000 which belongs to the cache kmalloc-4k of size 4096 [ +0.000008] The buggy address is located 1504 bytes inside of 4096-byte region [ffff000020c39000, ffff000020c3a000) [ +0.000016] The buggy address belongs to the physical page: [ +0.000009] page:fffffc0000830e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20c38 [ +0.000013] head:fffffc0000830e00 order:3 compound_mapcount:0 compound_pincount:0 [ +0.000008] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff) [ +0.000019] raw: 0ffff00000010200 fffffc0000fd4808 fffffc0000126208 ffff000000002e80 [ +0.000009] raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 [ +0.000008] page dumped because: kasan: bad access detected [ +0.000011] Memory state around the buggy address: [ +0.000008] ffff000020c39480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ +0.000007] ffff000020c39500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ +0.000007] >ffff000020c39580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ +0.000007] ^ [ +0.000007] ffff000020c39600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ +0.000007] ffff000020c39680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ +0.000006] ================================================================== The reason this is happening is unloading meson-dw-hdmi will cause the component API to take down the aggregate device, which in turn will cause all devres-managed memory to be freed, including the struct dw_hdmi allocated in dw_hdmi_probe. This struct embeds a struct drm_bridge that is added at the end of the function, and which is later on picked up in meson_encoder_hdmi_init. However, when attaching the bridge to the encoder created in meson_encoder_hdmi_init, it's linked to the encoder's bridge chain, from where it never leaves, even after devres_release_group is called when the driver's components are unbound and the embedding structure freed. Then, when calling drm_dev_put in the aggregate driver's unbind function, drm_bridge_detach is called for every single bridge linked to the encoder, including the one whose memory had already been deallocated. Fix by calling component_unbind_all after drm_dev_put. Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com> --- drivers/gpu/drm/meson/meson_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)