[PATCH AUTOSEL 5.19 29/36] drm/meson: explicitly remove aggregate driver at module unload time

Sasha Levin
2022-10-10T00:20:26Z

From: Adrián Larumbe <adrian.larumbe@collabora.com>

[ Upstream commit 8616f2a0589a80e08434212324250eb22f6a66ce ]

Because component_master_del wasn't being called when unloading the
meson_drm module, the aggregate device would linger forever in the global
aggregate_devices list. That means when unloading and reloading the
meson_dw_hdmi module, component_add would call into
try_to_bring_up_aggregate_device and find the unbound meson_drm aggregate
device.

This would in turn dereference some of the aggregate_device's struct
entries which point to memory automatically freed by the devres API when
unbinding the aggregate device from meson_drv_unbind, and trigger an
use-after-free bug:

[ +0.000014] =============================================================
[ +0.000007] BUG: KASAN: use-after-free in find_components+0x468/0x500
[ +0.000017] Read of size 8 at addr ffff000006731688 by task modprobe/2536
[ +0.000018] CPU: 4 PID: 2536 Comm: modprobe Tainted: G C O 5.19.0-rc6-lrmbkasan+ #1
[ +0.000010] Hardware name: Hardkernel ODROID-N2Plus (DT)
[ +0.000008] Call trace:
[ +0.000005] dump_backtrace+0x1ec/0x280
[ +0.000011] show_stack+0x24/0x80
[ +0.000007] dump_stack_lvl+0x98/0xd4
[ +0.000010] print_address_description.constprop.0+0x80/0x520
[ +0.000011] print_report+0x128/0x260
[ +0.000007] kasan_report+0xb8/0xfc
[ +0.000007] __asan_report_load8_noabort+0x3c/0x50
[ +0.000009] find_components+0x468/0x500
[ +0.000008] try_to_bring_up_aggregate_device+0x64/0x390
[ +0.000009] __component_add+0x1dc/0x49c
[ +0.000009] component_add+0x20/0x30
[ +0.000008] meson_dw_hdmi_probe+0x28/0x34 [meson_dw_hdmi]
[ +0.000013] platform_probe+0xd0/0x220
[ +0.000008] really_probe+0x3ac/0xa80
[ +0.000008] __driver_probe_device+0x1f8/0x400
[ +0.000008] driver_probe_device+0x68/0x1b0
[ +0.000008] __driver_attach+0x20c/0x480
[ +0.000009] bus_for_each_dev+0x114/0x1b0
[ +0.000007] driver_attach+0x48/0x64
[ +0.000009] bus_add_driver+0x390/0x564
[ +0.000007] driver_register+0x1a8/0x3e4
[ +0.000009] __platform_driver_register+0x6c/0x94
[ +0.000007] meson_dw_hdmi_platform_driver_init+0x30/0x1000 [meson_dw_hdmi]
[ +0.000014] do_one_initcall+0xc4/0x2b0
[ +0.000008] do_init_module+0x154/0x570
[ +0.000010] load_module+0x1a78/0x1ea4
[ +0.000008] __do_sys_init_module+0x184/0x1cc
[ +0.000008] __arm64_sys_init_module+0x78/0xb0
[ +0.000008] invoke_syscall+0x74/0x260
[ +0.000008] el0_svc_common.constprop.0+0xcc/0x260
[ +0.000009] do_el0_svc+0x50/0x70
[ +0.000008] el0_svc+0x68/0x1a0
[ +0.000009] el0t_64_sync_handler+0x11c/0x150
[ +0.000009] el0t_64_sync+0x18c/0x190

[ +0.000014] Allocated by task 902:
[ +0.000007] kasan_save_stack+0x2c/0x5c
[ +0.000009] __kasan_kmalloc+0x90/0xd0
[ +0.000007] __kmalloc_node+0x240/0x580
[ +0.000010] memcg_alloc_slab_cgroups+0xa4/0x1ac
[ +0.000010] memcg_slab_post_alloc_hook+0xbc/0x4c0
[ +0.000008] kmem_cache_alloc_node+0x1d0/0x490
[ +0.000009] __alloc_skb+0x1d4/0x310
[ +0.000010] alloc_skb_with_frags+0x8c/0x620
[ +0.000008] sock_alloc_send_pskb+0x5ac/0x6d0
[ +0.000010] unix_dgram_sendmsg+0x2e0/0x12f0
[ +0.000010] sock_sendmsg+0xcc/0x110
[ +0.000007] sock_write_iter+0x1d0/0x304
[ +0.000008] new_sync_write+0x364/0x460
[ +0.000007] vfs_write+0x420/0x5ac
[ +0.000008] ksys_write+0x19c/0x1f0
[ +0.000008] __arm64_sys_write+0x78/0xb0
[ +0.000007] invoke_syscall+0x74/0x260
[ +0.000008] el0_svc_common.constprop.0+0x1a8/0x260
[ +0.000009] do_el0_svc+0x50/0x70
[ +0.000007] el0_svc+0x68/0x1a0
[ +0.000008] el0t_64_sync_handler+0x11c/0x150
[ +0.000008] el0t_64_sync+0x18c/0x190

[ +0.000013] Freed by task 2509:
[ +0.000008] kasan_save_stack+0x2c/0x5c
[ +0.000007] kasan_set_track+0x2c/0x40
[ +0.000008] kasan_set_free_info+0x28/0x50
[ +0.000008] ____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
[ +0.000008] devres_release_all+0xfc/0x180
[ +0.000008] device_unbind_cleanup+0x24/0x164
[ +0.000008] device_release_driver_internal+0x3e8/0x5b0
[ +0.000010] driver_detach+0xac/0x1b0
[ +0.000008] bus_remove_driver+0x158/0x29c
[ +0.000008] driver_unregister+0x70/0xb0
[ +0.000009] platform_driver_unregister+0x20/0x2c
[ +0.000007] 0xffff800003722d98
[ +0.000012] __do_sys_delete_module+0x288/0x400
[ +0.000009] __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
[ +0.000008] el0t_64_sync_handler+0x11c/0x150
[ +0.000009] el0t_64_sync+0x18c/0x190

[ +0.000013] Last potentially related work creation:
[ +0.000007] kasan_save_stack+0x2c/0x5c
[ +0.000007] __kasan_record_aux_stack+0xb8/0xf0
[ +0.000009] kasan_record_aux_stack_noalloc+0x14/0x20
[ +0.000008] insert_work+0x54/0x290
[ +0.000009] __queue_work+0x48c/0xd24
[ +0.000008] queue_work_on+0x90/0x11c
[ +0.000008] call_usermodehelper_exec+0x188/0x404
[ +0.000010] kobject_uevent_env+0x5a8/0x794
[ +0.000010] kobject_uevent+0x14/0x20
[ +0.000008] driver_register+0x230/0x3e4
[ +0.000009] __platform_driver_register+0x6c/0x94
[ +0.000007] gxbb_driver_init+0x28/0x34
[ +0.000010] do_one_initcall+0xc4/0x2b0
[ +0.000008] do_initcalls+0x20c/0x24c
[ +0.000010] kernel_init_freeable+0x22c/0x278
[ +0.000009] kernel_init+0x3c/0x170
[ +0.000008] ret_from_fork+0x10/0x20

[ +0.000013] The buggy address belongs to the object at ffff000006731600
which belongs to the cache kmalloc-256 of size 256
[ +0.000009] The buggy address is located 136 bytes inside of
256-byte region [ffff000006731600, ffff000006731700)

[ +0.000015] The buggy address belongs to the physical page:
[ +0.000008] page:fffffc000019cc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff000006730a00 pfn:0x6730
[ +0.000011] head:fffffc000019cc00 order:2 compound_mapcount:0 compound_pincount:0
[ +0.000008] flags: 0xffff00000010200(slab|head|node=0|zone=0|lastcpupid=0xffff)
[ +0.000016] raw: 0ffff00000010200 fffffc00000c3d08 fffffc0000ef2b08 ffff000000002680
[ +0.000009] raw: ffff000006730a00 0000000000150014 00000001ffffffff 0000000000000000
[ +0.000006] page dumped because: kasan: bad access detected

[ +0.000011] Memory state around the buggy address:
[ +0.000007] ffff000006731580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ +0.000007] ffff000006731600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000007] >ffff000006731680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ +0.000007] ^
[ +0.000006] ffff000006731700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ +0.000007] ffff000006731780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ +0.000006] ==================================================================

Fix by adding 'remove' driver callback for meson-drm, and explicitly deleting the
aggregate device.

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/20220919010940.419893-3-adrian.larumbe@collabora.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/meson/meson_drv.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 7df149d42728..8444d90165fb 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -493,6 +493,13 @@ static int meson_drv_probe(struct platform_device *pdev)
return 0;
};

+static int meson_drv_remove(struct platform_device *pdev)
+{
+ component_master_del(&pdev->dev, &meson_drv_master_ops);
+
+ return 0;
+}
+
static struct meson_drm_match_data meson_drm_gxbb_data = {
.compat = VPU_COMPATIBLE_GXBB,
};
@@ -530,6 +537,7 @@ static const struct dev_pm_ops meson_drv_pm_ops = {

static struct platform_driver meson_drm_platform_driver = {
.probe = meson_drv_probe,
+ .remove = meson_drv_remove,
.shutdown = meson_drv_shutdown,
.driver = {
.name = "meson-drm",
--
2.35.1