When MST and atomic were introduced to nouveau, another structure that could contain a drm_connector embedded within it was introduced; struct nv50_mstc. This meant that we no longer would be able to simply loop through our connector list and assume that nouveau_connector() would return a proper pointer for each connector, since the assertion that all connectors coming from nouveau have a full nouveau_connector struct became invalid.

Unfortunately, none of the actual code that looped through connectors ever got updated, which means that we've been causing invalid memory accesses for quite a while now.

An example that was caught by KASAN:

[ 201.038698] ================================================================== [ 201.038792] BUG: KASAN: slab-out-of-bounds in nvif_notify_get+0x190/0x1a0 [nouveau] [ 201.038797] Read of size 4 at addr ffff88076738c650 by task kworker/0:3/718 [ 201.038800] [ 201.038822] CPU: 0 PID: 718 Comm: kworker/0:3 Tainted: G O 4.18.0-rc4Lyude-Test+ #1 [ 201.038825] Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET78W (1.51 ) 05/18/2018 [ 201.038882] Workqueue: events nouveau_display_hpd_work [nouveau] [ 201.038887] Call Trace: [ 201.038894] dump_stack+0xa4/0xfd [ 201.038900] print_address_description+0x71/0x239 [ 201.038929] ? nvif_notify_get+0x190/0x1a0 [nouveau] [ 201.038935] kasan_report.cold.6+0x242/0x2fe [ 201.038942] __asan_report_load4_noabort+0x19/0x20 [ 201.038970] nvif_notify_get+0x190/0x1a0 [nouveau] [ 201.038998] ? nvif_notify_put+0x1f0/0x1f0 [nouveau] [ 201.039003] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 201.039049] nouveau_display_init.cold.12+0x34/0x39 [nouveau] [ 201.039089] ? nouveau_user_framebuffer_create+0x120/0x120 [nouveau] [ 201.039133] nouveau_display_resume+0x5c0/0x810 [nouveau] [ 201.039173] ? nvkm_client_ioctl+0x20/0x20 [nouveau] [ 201.039215] nouveau_do_resume+0x19f/0x570 [nouveau] [ 201.039256] nouveau_pmops_runtime_resume+0xd8/0x2a0 [nouveau] [ 201.039264] pci_pm_runtime_resume+0x130/0x250 [ 201.039269] ? pci_restore_standard_config+0x70/0x70 [ 201.039275] __rpm_callback+0x1f2/0x5d0 [ 201.039279] ? rpm_resume+0x560/0x18a0 [ 201.039283] ? pci_restore_standard_config+0x70/0x70 [ 201.039287] ? pci_restore_standard_config+0x70/0x70 [ 201.039291] ? pci_restore_standard_config+0x70/0x70 [ 201.039296] rpm_callback+0x175/0x210 [ 201.039300] ? pci_restore_standard_config+0x70/0x70 [ 201.039305] rpm_resume+0xcc3/0x18a0 [ 201.039312] ? rpm_callback+0x210/0x210 [ 201.039317] ? __pm_runtime_resume+0x9e/0x100 [ 201.039322] ? kasan_check_write+0x14/0x20 [ 201.039326] ? do_raw_spin_lock+0xc2/0x1c0 [ 201.039333] __pm_runtime_resume+0xac/0x100 [ 201.039374] nouveau_display_hpd_work+0x67/0x1f0 [nouveau] [ 201.039380] process_one_work+0x7a0/0x14d0 [ 201.039388] ? cancel_delayed_work_sync+0x20/0x20 [ 201.039392] ? lock_acquire+0x113/0x310 [ 201.039398] ? kasan_check_write+0x14/0x20 [ 201.039402] ? do_raw_spin_lock+0xc2/0x1c0 [ 201.039409] worker_thread+0x86/0xb50 [ 201.039418] kthread+0x2e9/0x3a0 [ 201.039422] ? process_one_work+0x14d0/0x14d0 [ 201.039426] ? kthread_create_worker_on_cpu+0xc0/0xc0 [ 201.039431] ret_from_fork+0x3a/0x50 [ 201.039441] [ 201.039444] Allocated by task 79: [ 201.039449] save_stack+0x43/0xd0 [ 201.039452] kasan_kmalloc+0xc4/0xe0 [ 201.039456] kmem_cache_alloc_trace+0x10a/0x260 [ 201.039494] nv50_mstm_add_connector+0x9a/0x340 [nouveau] [ 201.039504] drm_dp_add_port+0xff5/0x1fc0 [drm_kms_helper] [ 201.039511] drm_dp_send_link_address+0x4a7/0x740 [drm_kms_helper] [ 201.039518] drm_dp_check_and_send_link_address+0x1a7/0x210 [drm_kms_helper] [ 201.039525] drm_dp_mst_link_probe_work+0x71/0xb0 [drm_kms_helper] [ 201.039529] process_one_work+0x7a0/0x14d0 [ 201.039533] worker_thread+0x86/0xb50 [ 201.039537] kthread+0x2e9/0x3a0 [ 201.039541] ret_from_fork+0x3a/0x50 [ 201.039543] [ 201.039546] Freed by task 0: [ 201.039549] (stack is not available) [ 201.039551] [ 201.039555] The buggy address belongs to the object at ffff88076738c1a8 which belongs to the cache kmalloc-2048 of size 2048 [ 201.039559] The buggy address is located 1192 bytes inside of 2048-byte region [ffff88076738c1a8, ffff88076738c9a8) [ 201.039563] The buggy address belongs to the page: [ 201.039567] page:ffffea001d9ce200 count:1 mapcount:0 mapping:ffff88084000d0c0 index:0x0 compound_mapcount: 0 [ 201.039573] flags: 0x8000000000008100(slab|head) [ 201.039578] raw: 8000000000008100 ffffea001da3be08 ffffea001da25a08 ffff88084000d0c0 [ 201.039582] raw: 0000000000000000 00000000000d000d 00000001ffffffff 0000000000000000 [ 201.039585] page dumped because: kasan: bad access detected [ 201.039588] [ 201.039591] Memory state around the buggy address: [ 201.039594] ffff88076738c500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 201.039598] ffff88076738c580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 201.039601] >ffff88076738c600: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc [ 201.039604] ^ [ 201.039607] ffff88076738c680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 201.039611] ffff88076738c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 201.039613] ==================================================================

Signed-off-by: Lyude Paul lyude@redhat.com Cc: stable@vger.kernel.org Cc: Karol Herbst karolherbst@gmail.com --- Changes since v2: - Use for_each_if (re: Daniel Vetter)

drivers/gpu/drm/nouveau/nouveau_connector.c | 2 +- drivers/gpu/drm/nouveau/nouveau_connector.h | 24 ++++++++++++++++++++- drivers/gpu/drm/nouveau/nouveau_display.c | 4 ++-- 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 7dc380449232..af68eae4c626 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -1213,7 +1213,7 @@ nouveau_connector_create(struct drm_device *dev, int index) bool dummy;

drm_connector_list_iter_begin(dev, &conn_iter); - drm_for_each_connector_iter(connector, &conn_iter) { + nouveau_for_each_non_mst_connector_iter(connector, &conn_iter) { nv_connector = nouveau_connector(connector); if (nv_connector->index == index) { drm_connector_list_iter_end(&conn_iter); diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.h b/drivers/gpu/drm/nouveau/nouveau_connector.h index a8cbb4b56fc7..dc7454e7f19a 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.h +++ b/drivers/gpu/drm/nouveau/nouveau_connector.h @@ -33,6 +33,7 @@ #include <drm/drm_encoder.h> #include <drm/drm_dp_helper.h> #include "nouveau_crtc.h" +#include "nouveau_encoder.h"

struct nvkm_i2c_port;

@@ -60,6 +61,27 @@ static inline struct nouveau_connector *nouveau_connector( return container_of(con, struct nouveau_connector, base); }

+static inline bool +nouveau_connector_is_mst(struct drm_connector *connector) +{ + const struct nouveau_encoder *nv_encoder; + const struct drm_encoder *encoder; + + if (connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort) + return false; + + nv_encoder = find_encoder(connector, DCB_OUTPUT_ANY); + if (!nv_encoder) + return false; + + encoder = &nv_encoder->base.base; + return encoder->encoder_type == DRM_MODE_ENCODER_DPMST; +} + +#define nouveau_for_each_non_mst_connector_iter(connector, iter) \ + drm_for_each_connector_iter(connector, iter) \ + for_each_if(!nouveau_connector_is_mst(connector)) + static inline struct nouveau_connector * nouveau_crtc_connector_get(struct nouveau_crtc *nv_crtc) { @@ -70,7 +92,7 @@ nouveau_crtc_connector_get(struct nouveau_crtc *nv_crtc) struct drm_crtc *crtc = to_drm_crtc(nv_crtc);

drm_connector_list_iter_begin(dev, &conn_iter); - drm_for_each_connector_iter(connector, &conn_iter) { + nouveau_for_each_non_mst_connector_iter(connector, &conn_iter) { if (connector->encoder && connector->encoder->crtc == crtc) { nv_connector = nouveau_connector(connector); break; diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c index 46b8430ef4aa..ec7861457b84 100644 --- a/drivers/gpu/drm/nouveau/nouveau_display.c +++ b/drivers/gpu/drm/nouveau/nouveau_display.c @@ -413,7 +413,7 @@ nouveau_display_init(struct drm_device *dev)

/* enable hotplug interrupts */ drm_connector_list_iter_begin(dev, &conn_iter); - drm_for_each_connector_iter(connector, &conn_iter) { + nouveau_for_each_non_mst_connector_iter(connector, &conn_iter) { struct nouveau_connector *conn = nouveau_connector(connector); nvif_notify_get(&conn->hpd); } @@ -444,7 +444,7 @@ nouveau_display_fini(struct drm_device *dev, bool suspend)

/* disable hotplug interrupts */ drm_connector_list_iter_begin(dev, &conn_iter); - drm_for_each_connector_iter(connector, &conn_iter) { + nouveau_for_each_non_mst_connector_iter(connector, &conn_iter) { struct nouveau_connector *conn = nouveau_connector(connector); nvif_notify_put(&conn->hpd); }