09847723c1
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@collabora.com> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220920222842.1053234-1-adrian.larumbe@collabora.com
Linux kernel
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