Thanks for the catch! Makes sense to skip disabled managers there, but I wonder why it didn't cause a crash with amdgpu. Anyways looks good to me.
Acked-by: Mikita Lipski mikita.lipski@amd.com
On 1/16/20 8:58 PM, José Roberto de Souza wrote:
When a main MST port is disconnected drivers should call drm_dp_mst_topology_mgr_set_mst() disabling the MST manager, this function will set manager mst_primary to NULL and it will cause the crash bellow on the next atomic check when trying to access mst_primary->port.
As there is no use in running checks over managers that are not active this patch will skip it.
[ 305.616450] [drm:drm_dp_mst_atomic_check] [MST PORT:00000000cc2049e9] releases all VCPI slots [ 305.625085] [drm:drm_dp_mst_atomic_check] [MST PORT:00000000020ab43e] releases all VCPI slots [ 305.633729] [drm:drm_dp_mst_atomic_check] [MST MGR:00000000cdd467d4] mst state 00000000b67672eb VCPI avail=63 used=0 [ 305.644405] BUG: kernel NULL pointer dereference, address: 0000000000000030 [ 305.651448] #PF: supervisor read access in kernel mode [ 305.656640] #PF: error_code(0x0000) - not-present page [ 305.661807] PGD 0 P4D 0 [ 305.664396] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 305.668789] CPU: 3 PID: 183 Comm: kworker/3:2 Not tainted 5.5.0-rc6+ #1404 [ 305.675703] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3201.A00.1905140358 05/14/2019 [ 305.689425] Workqueue: events drm_dp_delayed_destroy_work [ 305.694874] RIP: 0010:drm_dp_mst_atomic_check+0x138/0x2c0 [ 305.700306] Code: 00 00 00 41 29 d9 41 89 d8 4c 89 fa 4c 89 f1 48 c7 c6 b0 b1 34 82 bf 10 00 00 00 45 31 ed e8 3f 99 02 00 4d 8b bf 80 04 00 00 <49> 8b 47 30 49 8d 5f 30 4c 8d 60 e8 48 39 c3 74 35 49 8b 7c 24 28 [ 305.719169] RSP: 0018:ffffc90001687b58 EFLAGS: 00010246 [ 305.724434] RAX: 0000000000000000 RBX: 000000000000003f RCX: 0000000000000000 [ 305.731611] RDX: 0000000000000000 RSI: ffff88849fba8cb8 RDI: 00000000ffffffff [ 305.738785] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 305.745962] R10: ffffc900016879a0 R11: ffffc900016879a5 R12: 0000000000000000 [ 305.753139] R13: 0000000000000000 R14: ffff8884905c9bc0 R15: 0000000000000000 [ 305.760315] FS: 0000000000000000(0000) GS:ffff88849fb80000(0000) knlGS:0000000000000000 [ 305.768452] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 305.774263] CR2: 0000000000000030 CR3: 0000000005610006 CR4: 0000000000760ee0 [ 305.781441] PKRU: 55555554 [ 305.784228] Call Trace: [ 305.786739] intel_atomic_check+0xb2e/0x2560 [i915] [ 305.791678] ? printk+0x53/0x6a [ 305.794856] ? drm_atomic_check_only+0x3e/0x810 [ 305.799417] ? __drm_dbg+0x82/0x90 [ 305.802848] drm_atomic_check_only+0x56a/0x810 [ 305.807322] drm_atomic_commit+0xe/0x50 [ 305.811185] drm_client_modeset_commit_atomic+0x1e2/0x250 [ 305.816619] drm_client_modeset_commit_force+0x4d/0x180 [ 305.821921] drm_fb_helper_restore_fbdev_mode_unlocked+0x46/0xa0 [ 305.827963] drm_fb_helper_set_par+0x2b/0x40 [ 305.832265] drm_fb_helper_hotplug_event.part.0+0xb2/0xd0 [ 305.837755] drm_kms_helper_hotplug_event+0x21/0x30 [ 305.842694] process_one_work+0x25b/0x5b0 [ 305.846735] worker_thread+0x4b/0x3b0 [ 305.850439] kthread+0x100/0x140 [ 305.853690] ? process_one_work+0x5b0/0x5b0 [ 305.857901] ? kthread_park+0x80/0x80 [ 305.861588] ret_from_fork+0x24/0x50 [ 305.865202] Modules linked in: snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 btusb btrtl btbcm btintel bluetooth prime_numbers snd_hda_intel snd_intel_dspcfg snd_hda_codec e1000e snd_hwdep snd_hda_core thunderbolt mei_hdcp mei_me asix cdc_ether x86_pkg_temp_thermal r8152 mei coretemp usbnet snd_pcm mii crct10dif_pclmul ptp crc32_pclmul ecdh_generic ghash_clmulni_intel pps_core ecc i2c_i801 intel_lpss_pci [ 305.903096] CR2: 0000000000000030 [ 305.906431] ---[ end trace 70ee364eed801cb0 ]--- [ 305.940816] RIP: 0010:drm_dp_mst_atomic_check+0x138/0x2c0 [ 305.946261] Code: 00 00 00 41 29 d9 41 89 d8 4c 89 fa 4c 89 f1 48 c7 c6 b0 b1 34 82 bf 10 00 00 00 45 31 ed e8 3f 99 02 00 4d 8b bf 80 04 00 00 <49> 8b 47 30 49 8d 5f 30 4c 8d 60 e8 48 39 c3 74 35 49 8b 7c 24 28 [ 305.965125] RSP: 0018:ffffc90001687b58 EFLAGS: 00010246 [ 305.970382] RAX: 0000000000000000 RBX: 000000000000003f RCX: 0000000000000000 [ 305.977571] RDX: 0000000000000000 RSI: ffff88849fba8cb8 RDI: 00000000ffffffff [ 305.984747] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 305.991921] R10: ffffc900016879a0 R11: ffffc900016879a5 R12: 0000000000000000 [ 305.999099] R13: 0000000000000000 R14: ffff8884905c9bc0 R15: 0000000000000000 [ 306.006271] FS: 0000000000000000(0000) GS:ffff88849fb80000(0000) knlGS:0000000000000000 [ 306.014407] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 306.020185] CR2: 0000000000000030 CR3: 000000048b3aa003 CR4: 0000000000760ee0 [ 306.027404] PKRU: 55555554 [ 306.030127] BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:38 [ 306.039049] in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 183, name: kworker/3:2 [ 306.047272] INFO: lockdep is turned off. [ 306.051217] irq event stamp: 77505 [ 306.054647] hardirqs last enabled at (77505): [<ffffffff81a0c147>] _raw_spin_unlock_irqrestore+0x47/0x60 [ 306.064270] hardirqs last disabled at (77504): [<ffffffff81a0bedf>] _raw_spin_lock_irqsave+0xf/0x50 [ 306.073404] softirqs last enabled at (77402): [<ffffffff81e00389>] __do_softirq+0x389/0x47f [ 306.081885] softirqs last disabled at (77395): [<ffffffff810b83a9>] irq_exit+0xa9/0xc0 [ 306.089859] CPU: 3 PID: 183 Comm: kworker/3:2 Tainted: G D 5.5.0-rc6+ #1404 [ 306.098167] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3201.A00.1905140358 05/14/2019 [ 306.111882] Workqueue: events drm_dp_delayed_destroy_work [ 306.117314] Call Trace: [ 306.119780] dump_stack+0x71/0xa0 [ 306.123135] ___might_sleep.cold+0xf7/0x10b [ 306.127399] exit_signals+0x2b/0x360 [ 306.131014] do_exit+0xa7/0xc70 [ 306.134189] ? kthread+0x100/0x140 [ 306.137615] rewind_stack_do_exit+0x17/0x20
Fixes: cd82d82cbc04 ("drm/dp_mst: Add branch bandwidth validation to MST atomic check") Cc: Mikita Lipski mikita.lipski@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Lyude Paul lyude@redhat.com Signed-off-by: José Roberto de Souza jose.souza@intel.com
drivers/gpu/drm/drm_dp_mst_topology.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 4b74193b89ce..38bf111e5f9b 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -5034,6 +5034,9 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state *state) int i, ret = 0;
for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
if (!mgr->mst_state)continue;- ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state); if (ret) break;