From c54c7374ff44de5e609506aca7c0deae4703b6d1 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Tue, 13 Nov 2018 17:46:14 -0500 Subject: [PATCH 1/7] drm/dp_mst: Skip validating ports during destruction, just ref Jerry Zuo pointed out a rather obscure hotplugging issue that it seems I accidentally introduced into DRM two years ago. Pretend we have a topology like this: |- DP-1: mst_primary |- DP-4: active display |- DP-5: disconnected |- DP-6: active hub |- DP-7: active display |- DP-8: disconnected |- DP-9: disconnected If we unplug DP-6, the topology starting at DP-7 will be destroyed but it's payloads will live on in DP-1's VCPI allocations and thus require removal. However, this removal currently fails because drm_dp_update_payload_part1() will (rightly so) try to validate the port before accessing it, fail then abort. If we keep going, eventually we run the MST hub out of bandwidth and all new allocations will start to fail (or in my case; all new displays just start flickering a ton). We could just teach drm_dp_update_payload_part1() not to drop the port ref in this case, but then we also need to teach drm_dp_destroy_payload_step1() to do the same thing, then hope no one ever adds anything to the that requires a validated port reference in drm_dp_destroy_connector_work(). Kind of sketchy. So let's go with a more clever solution: any port that drm_dp_destroy_connector_work() interacts with is guaranteed to still exist in memory until we say so. While said port might not be valid we don't really care: that's the whole reason we're destroying it in the first place! So, teach drm_dp_get_validated_port_ref() to use the all mighty current_work() function to avoid attempting to validate ports from the context of mgr->destroy_connector_work. I can't see any situation where this wouldn't be safe, and this avoids having to play whack-a-mole in the future of trying to work around port validation. Signed-off-by: Lyude Paul Fixes: 263efde31f97 ("drm/dp/mst: Get validated port ref in drm_dp_update_payload_part1()") Reported-by: Jerry Zuo Cc: Jerry Zuo Cc: Harry Wentland Cc: # v4.6+ Reviewed-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20181113224613.28809-1-lyude@redhat.com Signed-off-by: Sean Paul --- drivers/gpu/drm/drm_dp_mst_topology.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 0e0df398222d..250d7160826f 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -1023,9 +1023,20 @@ static struct drm_dp_mst_port *drm_dp_mst_get_port_ref_locked(struct drm_dp_mst_ static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port) { struct drm_dp_mst_port *rport = NULL; + mutex_lock(&mgr->lock); - if (mgr->mst_primary) - rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port); + /* + * Port may or may not be 'valid' but we don't care about that when + * destroying the port and we are guaranteed that the port pointer + * will be valid until we've finished + */ + if (current_work() == &mgr->destroy_connector_work) { + kref_get(&port->kref); + rport = port; + } else if (mgr->mst_primary) { + rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, + port); + } mutex_unlock(&mgr->lock); return rport; } From 23a336b34258aba3b50ea6863cca4e81b5ef6384 Mon Sep 17 00:00:00 2001 From: Sergio Correia Date: Thu, 22 Nov 2018 02:33:29 -0300 Subject: [PATCH 2/7] drm: set is_master to 0 upon drm_new_set_master() failure When drm_new_set_master() fails, set is_master to 0, to prevent a possible NULL pointer deref. Here is a problematic flow: we check is_master in drm_is_current_master(), then proceed to call drm_lease_owner() passing master. If we do not restore is_master status when drm_new_set_master() fails, we may have a situation in which is_master will be 1 and master itself, NULL, leading to the deref of a NULL pointer in drm_lease_owner(). This fixes the following OOPS, observed on an ArchLinux running a 4.19.2 kernel: [ 97.804282] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 97.807224] PGD 0 P4D 0 [ 97.807224] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 97.807224] CPU: 0 PID: 1348 Comm: xfwm4 Tainted: P OE 4.19.2-arch1-1-ARCH #1 [ 97.807224] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./AB350 Pro4, BIOS P5.10 10/16/2018 [ 97.807224] RIP: 0010:drm_lease_owner+0xd/0x20 [drm] [ 97.807224] Code: 83 c4 18 5b 5d c3 b8 ea ff ff ff eb e2 b8 ed ff ff ff eb db e8 b4 ca 68 fb 0f 1f 40 00 0f 1f 44 00 00 48 89 f8 eb 03 48 89 d0 <48> 8b 90 80 00 00 00 48 85 d2 75 f1 c3 66 0f 1f 44 00 00 0f 1f 44 [ 97.807224] RSP: 0018:ffffb8cf08e07bb0 EFLAGS: 00010202 [ 97.807224] RAX: 0000000000000000 RBX: ffff9cf0f2586c00 RCX: ffff9cf0f2586c88 [ 97.807224] RDX: ffff9cf0ddbd8000 RSI: 0000000000000000 RDI: 0000000000000000 [ 97.807224] RBP: ffff9cf1040e9800 R08: 0000000000000000 R09: 0000000000000000 [ 97.807224] R10: ffffdeb30fd5d680 R11: ffffdeb30f5d6808 R12: ffff9cf1040e9888 [ 97.807224] R13: 0000000000000000 R14: dead000000000200 R15: ffff9cf0f2586cc8 [ 97.807224] FS: 00007f4145513180(0000) GS:ffff9cf10ea00000(0000) knlGS:0000000000000000 [ 97.807224] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 97.807224] CR2: 0000000000000080 CR3: 00000003d7548000 CR4: 00000000003406f0 [ 97.807224] Call Trace: [ 97.807224] drm_is_current_master+0x1a/0x30 [drm] [ 97.807224] drm_master_release+0x3e/0x130 [drm] [ 97.807224] drm_file_free.part.0+0x2be/0x2d0 [drm] [ 97.807224] drm_open+0x1ba/0x1e0 [drm] [ 97.807224] drm_stub_open+0xaf/0xe0 [drm] [ 97.807224] chrdev_open+0xa3/0x1b0 [ 97.807224] ? cdev_put.part.0+0x20/0x20 [ 97.807224] do_dentry_open+0x132/0x340 [ 97.807224] path_openat+0x2d1/0x14e0 [ 97.807224] ? mem_cgroup_commit_charge+0x7a/0x520 [ 97.807224] do_filp_open+0x93/0x100 [ 97.807224] ? __check_object_size+0x102/0x189 [ 97.807224] ? _raw_spin_unlock+0x16/0x30 [ 97.807224] do_sys_open+0x186/0x210 [ 97.807224] do_syscall_64+0x5b/0x170 [ 97.807224] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 97.807224] RIP: 0033:0x7f4147b07976 [ 97.807224] Code: 89 54 24 08 e8 7b f4 ff ff 8b 74 24 0c 48 8b 3c 24 41 89 c0 44 8b 54 24 08 b8 01 01 00 00 89 f2 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 30 44 89 c7 89 44 24 08 e8 a6 f4 ff ff 8b 44 [ 97.807224] RSP: 002b:00007ffcced96ca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 [ 97.807224] RAX: ffffffffffffffda RBX: 00005619d5037f80 RCX: 00007f4147b07976 [ 97.807224] RDX: 0000000000000002 RSI: 00005619d46b969c RDI: 00000000ffffff9c [ 98.040039] RBP: 0000000000000024 R08: 0000000000000000 R09: 0000000000000000 [ 98.040039] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000024 [ 98.040039] R13: 0000000000000012 R14: 00005619d5035950 R15: 0000000000000012 [ 98.040039] Modules linked in: nct6775 hwmon_vid algif_skcipher af_alg nls_iso8859_1 nls_cp437 vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common arc4 videodev media snd_usb_audio snd_hda_codec_hdmi snd_usbmidi_lib snd_rawmidi snd_seq_device mousedev input_leds iwlmvm mac80211 snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec edac_mce_amd kvm_amd snd_hda_core kvm iwlwifi snd_hwdep r8169 wmi_bmof cfg80211 snd_pcm irqbypass snd_timer snd libphy soundcore pinctrl_amd rfkill pcspkr sp5100_tco evdev gpio_amdpt k10temp mac_hid i2c_piix4 wmi pcc_cpufreq acpi_cpufreq vboxnetflt(OE) vboxnetadp(OE) vboxpci(OE) vboxdrv(OE) msr sg crypto_user ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 fscrypto uas usb_storage dm_crypt hid_generic usbhid hid [ 98.040039] dm_mod raid1 md_mod sd_mod crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pcbc ahci libahci aesni_intel aes_x86_64 libata crypto_simd cryptd glue_helper ccp xhci_pci rng_core scsi_mod xhci_hcd nvidia_drm(POE) drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm agpgart nvidia_uvm(POE) nvidia_modeset(POE) nvidia(POE) ipmi_devintf ipmi_msghandler [ 98.040039] CR2: 0000000000000080 [ 98.040039] ---[ end trace 3b65093b6fe62b2f ]--- [ 98.040039] RIP: 0010:drm_lease_owner+0xd/0x20 [drm] [ 98.040039] Code: 83 c4 18 5b 5d c3 b8 ea ff ff ff eb e2 b8 ed ff ff ff eb db e8 b4 ca 68 fb 0f 1f 40 00 0f 1f 44 00 00 48 89 f8 eb 03 48 89 d0 <48> 8b 90 80 00 00 00 48 85 d2 75 f1 c3 66 0f 1f 44 00 00 0f 1f 44 [ 98.040039] RSP: 0018:ffffb8cf08e07bb0 EFLAGS: 00010202 [ 98.040039] RAX: 0000000000000000 RBX: ffff9cf0f2586c00 RCX: ffff9cf0f2586c88 [ 98.040039] RDX: ffff9cf0ddbd8000 RSI: 0000000000000000 RDI: 0000000000000000 [ 98.040039] RBP: ffff9cf1040e9800 R08: 0000000000000000 R09: 0000000000000000 [ 98.040039] R10: ffffdeb30fd5d680 R11: ffffdeb30f5d6808 R12: ffff9cf1040e9888 [ 98.040039] R13: 0000000000000000 R14: dead000000000200 R15: ffff9cf0f2586cc8 [ 98.040039] FS: 00007f4145513180(0000) GS:ffff9cf10ea00000(0000) knlGS:0000000000000000 [ 98.040039] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 98.040039] CR2: 0000000000000080 CR3: 00000003d7548000 CR4: 00000000003406f0 Signed-off-by: Sergio Correia Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20181122053329.2692-1-sergio@correia.cc Signed-off-by: Sean Paul --- drivers/gpu/drm/drm_auth.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c index d9c0f7573905..1669c42c40ed 100644 --- a/drivers/gpu/drm/drm_auth.c +++ b/drivers/gpu/drm/drm_auth.c @@ -142,6 +142,7 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv) lockdep_assert_held_once(&dev->master_mutex); + WARN_ON(fpriv->is_master); old_master = fpriv->master; fpriv->master = drm_master_create(dev); if (!fpriv->master) { @@ -170,6 +171,7 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv) /* drop references and restore old master on failure */ drm_master_put(&fpriv->master); fpriv->master = old_master; + fpriv->is_master = 0; return ret; } From 2bcd3ecab773f73211c45bb1430bb52ac641f271 Mon Sep 17 00:00:00 2001 From: Neil Armstrong Date: Thu, 22 Nov 2018 17:01:03 +0100 Subject: [PATCH 3/7] drm/meson: Fixes for drm_crtc_vblank_on/off support Since Linux 4.17, calls to drm_crtc_vblank_on/off are mandatory, and we get a warning when ctrc is disabled : " driver forgot to call drm_crtc_vblank_off()" But, the vsync IRQ was not totally disabled due the transient hardware state and specific interrupt line, thus adding proper IRQ masking from the HHI system control registers. The last change fixes a race condition introduced by calling the added drm_crtc_vblank_on/off when an HPD event occurs from the HDMI connector, triggering a WARN_ON() in the _atomic_begin() callback when the CRTC is disabled, thus also triggering a WARN_ON() in drm_vblank_put() : WARNING: CPU: 0 PID: 1185 at drivers/gpu/drm/meson/meson_crtc.c:157 meson_crtc_atomic_begin+0x78/0x80 [...] Call trace: meson_crtc_atomic_begin+0x78/0x80 drm_atomic_helper_commit_planes+0x140/0x218 drm_atomic_helper_commit_tail+0x38/0x80 commit_tail+0x7c/0x80 drm_atomic_helper_commit+0xdc/0x150 drm_atomic_commit+0x54/0x60 restore_fbdev_mode_atomic+0x198/0x238 restore_fbdev_mode+0x6c/0x1c0 drm_fb_helper_restore_fbdev_mode_unlocked+0x7c/0xf0 drm_fb_helper_set_par+0x34/0x60 drm_fb_helper_hotplug_event.part.28+0xb8/0xc8 drm_fbdev_client_hotplug+0xa4/0xe0 drm_client_dev_hotplug+0x90/0xe0 drm_kms_helper_hotplug_event+0x3c/0x48 drm_helper_hpd_irq_event+0x134/0x168 dw_hdmi_top_thread_irq+0x3c/0x50 [...] WARNING: CPU: 0 PID: 1185 at drivers/gpu/drm/drm_vblank.c:1026 drm_vblank_put+0xb4/0xc8 [...] Call trace: drm_vblank_put+0xb4/0xc8 drm_crtc_vblank_put+0x24/0x30 drm_atomic_helper_wait_for_vblanks.part.9+0x130/0x2b8 drm_atomic_helper_commit_tail+0x68/0x80 [...] The issue is that vblank need to be enabled in any occurrence of : - atomic_enable() - atomic_begin() and state->enable == true, which was not the case Moving the CRTC enable code to a common function and calling in one of these occurrence solves this race condition and makes sure vblank is enabled in each call to _atomic_begin() from the HPD event leading to drm_atomic_helper_commit_planes(). To Summarize : - Make sure that the CRTC code will call the drm_crtc_vblank_on()/off() - *Really* mask the Vsync IRQ - Initialize and enable vblank at the first atomic_begin()/_atomic_enable() Cc: stable@vger.kernel.org # 4.17+ Signed-off-by: Neil Armstrong Reviewed-by: Lyude Paul [fixed typos+added cc for stable] Signed-off-by: Lyude Paul Link: https://patchwork.freedesktop.org/patch/msgid/20181122160103.10993-1-narmstrong@baylibre.com Signed-off-by: Sean Paul --- drivers/gpu/drm/meson/meson_crtc.c | 27 +++++++++++++++++++++++++-- drivers/gpu/drm/meson/meson_venc.c | 3 +++ 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/meson/meson_crtc.c b/drivers/gpu/drm/meson/meson_crtc.c index 05520202c967..191b314f9e9e 100644 --- a/drivers/gpu/drm/meson/meson_crtc.c +++ b/drivers/gpu/drm/meson/meson_crtc.c @@ -45,6 +45,7 @@ struct meson_crtc { struct drm_crtc base; struct drm_pending_vblank_event *event; struct meson_drm *priv; + bool enabled; }; #define to_meson_crtc(x) container_of(x, struct meson_crtc, base) @@ -80,8 +81,7 @@ static const struct drm_crtc_funcs meson_crtc_funcs = { }; -static void meson_crtc_atomic_enable(struct drm_crtc *crtc, - struct drm_crtc_state *old_state) +static void meson_crtc_enable(struct drm_crtc *crtc) { struct meson_crtc *meson_crtc = to_meson_crtc(crtc); struct drm_crtc_state *crtc_state = crtc->state; @@ -101,6 +101,22 @@ static void meson_crtc_atomic_enable(struct drm_crtc *crtc, writel_bits_relaxed(VPP_POSTBLEND_ENABLE, VPP_POSTBLEND_ENABLE, priv->io_base + _REG(VPP_MISC)); + drm_crtc_vblank_on(crtc); + + meson_crtc->enabled = true; +} + +static void meson_crtc_atomic_enable(struct drm_crtc *crtc, + struct drm_crtc_state *old_state) +{ + struct meson_crtc *meson_crtc = to_meson_crtc(crtc); + struct meson_drm *priv = meson_crtc->priv; + + DRM_DEBUG_DRIVER("\n"); + + if (!meson_crtc->enabled) + meson_crtc_enable(crtc); + priv->viu.osd1_enabled = true; } @@ -110,6 +126,8 @@ static void meson_crtc_atomic_disable(struct drm_crtc *crtc, struct meson_crtc *meson_crtc = to_meson_crtc(crtc); struct meson_drm *priv = meson_crtc->priv; + drm_crtc_vblank_off(crtc); + priv->viu.osd1_enabled = false; priv->viu.osd1_commit = false; @@ -124,6 +142,8 @@ static void meson_crtc_atomic_disable(struct drm_crtc *crtc, crtc->state->event = NULL; } + + meson_crtc->enabled = false; } static void meson_crtc_atomic_begin(struct drm_crtc *crtc, @@ -132,6 +152,9 @@ static void meson_crtc_atomic_begin(struct drm_crtc *crtc, struct meson_crtc *meson_crtc = to_meson_crtc(crtc); unsigned long flags; + if (crtc->state->enable && !meson_crtc->enabled) + meson_crtc_enable(crtc); + if (crtc->state->event) { WARN_ON(drm_crtc_vblank_get(crtc) != 0); diff --git a/drivers/gpu/drm/meson/meson_venc.c b/drivers/gpu/drm/meson/meson_venc.c index acbbad3e322c..2f9c3814a290 100644 --- a/drivers/gpu/drm/meson/meson_venc.c +++ b/drivers/gpu/drm/meson/meson_venc.c @@ -71,6 +71,7 @@ */ /* HHI Registers */ +#define HHI_GCLK_MPEG2 0x148 /* 0x52 offset in data sheet */ #define HHI_VDAC_CNTL0 0x2F4 /* 0xbd offset in data sheet */ #define HHI_VDAC_CNTL1 0x2F8 /* 0xbe offset in data sheet */ #define HHI_HDMI_PHY_CNTL0 0x3a0 /* 0xe8 offset in data sheet */ @@ -1530,10 +1531,12 @@ unsigned int meson_venci_get_field(struct meson_drm *priv) void meson_venc_enable_vsync(struct meson_drm *priv) { writel_relaxed(2, priv->io_base + _REG(VENC_INTCTRL)); + regmap_update_bits(priv->hhi, HHI_GCLK_MPEG2, BIT(25), BIT(25)); } void meson_venc_disable_vsync(struct meson_drm *priv) { + regmap_update_bits(priv->hhi, HHI_GCLK_MPEG2, BIT(25), 0); writel_relaxed(0, priv->io_base + _REG(VENC_INTCTRL)); } From 995b278e4723b26f8ebf0e7c119286d16c712747 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Sat, 24 Nov 2018 14:12:38 -0500 Subject: [PATCH 4/7] drm/meson: Enable fast_io in meson_dw_hdmi_regmap_config Seeing as we use this registermap in the context of our IRQ handlers, we need to be using spinlocks for reading/writing registers so that we can still read them from IRQ handlers without having to grab any mutexes and accidentally sleep. We don't currently do this, as pointed out by lockdep: [ 18.403770] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908 [ 18.406744] in_atomic(): 1, irqs_disabled(): 128, pid: 68, name: kworker/u17:0 [ 18.413864] INFO: lockdep is turned off. [ 18.417675] irq event stamp: 12 [ 18.420778] hardirqs last enabled at (11): [] _raw_spin_unlock_irq+0x2c/0x60 [ 18.429510] hardirqs last disabled at (12): [] __schedule+0xc4/0xa60 [ 18.437345] softirqs last enabled at (0): [] copy_process.isra.4.part.5+0x4d8/0x1c50 [ 18.446684] softirqs last disabled at (0): [<0000000000000000>] (null) [ 18.453979] CPU: 0 PID: 68 Comm: kworker/u17:0 Tainted: G W O 4.20.0-rc3Lyude-Test+ #9 [ 18.469839] Hardware name: amlogic khadas-vim2/khadas-vim2, BIOS 2018.07-rc2-armbian 09/11/2018 [ 18.480037] Workqueue: hci0 hci_power_on [bluetooth] [ 18.487138] Call trace: [ 18.494192] dump_backtrace+0x0/0x1b8 [ 18.501280] show_stack+0x14/0x20 [ 18.508361] dump_stack+0xbc/0xf4 [ 18.515427] ___might_sleep+0x140/0x1d8 [ 18.522515] __might_sleep+0x50/0x88 [ 18.529582] __mutex_lock+0x60/0x870 [ 18.536621] mutex_lock_nested+0x1c/0x28 [ 18.543660] regmap_lock_mutex+0x10/0x18 [ 18.550696] regmap_read+0x38/0x70 [ 18.557727] dw_hdmi_hardirq+0x58/0x138 [dw_hdmi] [ 18.564804] __handle_irq_event_percpu+0xac/0x410 [ 18.571891] handle_irq_event_percpu+0x34/0x88 [ 18.578982] handle_irq_event+0x48/0x78 [ 18.586051] handle_fasteoi_irq+0xac/0x160 [ 18.593061] generic_handle_irq+0x24/0x38 [ 18.599989] __handle_domain_irq+0x60/0xb8 [ 18.606857] gic_handle_irq+0x50/0xa0 [ 18.613659] el1_irq+0xb4/0x130 [ 18.620394] debug_lockdep_rcu_enabled+0x2c/0x30 [ 18.627111] schedule+0x38/0xa0 [ 18.633781] schedule_timeout+0x3a8/0x510 [ 18.640389] wait_for_common+0x15c/0x180 [ 18.646905] wait_for_completion+0x14/0x20 [ 18.653319] mmc_wait_for_req_done+0x28/0x168 [ 18.659693] mmc_wait_for_req+0xa8/0xe8 [ 18.665978] mmc_wait_for_cmd+0x64/0x98 [ 18.672180] mmc_io_rw_direct_host+0x94/0x130 [ 18.678385] mmc_io_rw_direct+0x10/0x18 [ 18.684516] sdio_enable_func+0xe8/0x1d0 [ 18.690627] btsdio_open+0x24/0xc0 [btsdio] [ 18.696821] hci_dev_do_open+0x64/0x598 [bluetooth] [ 18.703025] hci_power_on+0x50/0x270 [bluetooth] [ 18.709163] process_one_work+0x2a0/0x6e0 [ 18.715252] worker_thread+0x40/0x448 [ 18.721310] kthread+0x12c/0x130 [ 18.727326] ret_from_fork+0x10/0x1c [ 18.735555] ------------[ cut here ]------------ [ 18.741430] do not call blocking ops when !TASK_RUNNING; state=2 set at [<000000006265ec59>] wait_for_common+0x140/0x180 [ 18.752417] WARNING: CPU: 0 PID: 68 at kernel/sched/core.c:6096 __might_sleep+0x7c/0x88 [ 18.760553] Modules linked in: dm_mirror dm_region_hash dm_log dm_mod btsdio bluetooth snd_soc_hdmi_codec dw_hdmi_i2s_audio ecdh_generic brcmfmac brcmutil cfg80211 rfkill ir_nec_decoder meson_dw_hdmi(O) dw_hdmi rc_geekbox meson_rng meson_ir ao_cec rng_core rc_core cec leds_pwm efivars nfsd ip_tables x_tables crc32_generic f2fs uas meson_gxbb_wdt pwm_meson efivarfs ipv6 [ 18.799469] CPU: 0 PID: 68 Comm: kworker/u17:0 Tainted: G W O 4.20.0-rc3Lyude-Test+ #9 [ 18.808858] Hardware name: amlogic khadas-vim2/khadas-vim2, BIOS 2018.07-rc2-armbian 09/11/2018 [ 18.818045] Workqueue: hci0 hci_power_on [bluetooth] [ 18.824088] pstate: 80000085 (Nzcv daIf -PAN -UAO) [ 18.829891] pc : __might_sleep+0x7c/0x88 [ 18.835722] lr : __might_sleep+0x7c/0x88 [ 18.841256] sp : ffff000008003cb0 [ 18.846751] x29: ffff000008003cb0 x28: 0000000000000000 [ 18.852269] x27: ffff00000938e000 x26: ffff800010283000 [ 18.857726] x25: ffff800010353280 x24: ffff00000868ef50 [ 18.863166] x23: 0000000000000000 x22: 0000000000000000 [ 18.868551] x21: 0000000000000000 x20: 000000000000038c [ 18.873850] x19: ffff000008cd08c0 x18: 0000000000000010 [ 18.879081] x17: ffff000008a68cb0 x16: 0000000000000000 [ 18.884197] x15: 0000000000aaaaaa x14: 0e200e200e200e20 [ 18.889239] x13: 0000000000000001 x12: 00000000ffffffff [ 18.894261] x11: ffff000008adfa48 x10: 0000000000000001 [ 18.899517] x9 : ffff0000092a0158 x8 : 0000000000000000 [ 18.904674] x7 : ffff00000812136c x6 : 0000000000000000 [ 18.909895] x5 : 0000000000000000 x4 : 0000000000000001 [ 18.915080] x3 : 0000000000000007 x2 : 0000000000000007 [ 18.920269] x1 : 99ab8e9ebb6c8500 x0 : 0000000000000000 [ 18.925443] Call trace: [ 18.929904] __might_sleep+0x7c/0x88 [ 18.934311] __mutex_lock+0x60/0x870 [ 18.938687] mutex_lock_nested+0x1c/0x28 [ 18.943076] regmap_lock_mutex+0x10/0x18 [ 18.947453] regmap_read+0x38/0x70 [ 18.951842] dw_hdmi_hardirq+0x58/0x138 [dw_hdmi] [ 18.956269] __handle_irq_event_percpu+0xac/0x410 [ 18.960712] handle_irq_event_percpu+0x34/0x88 [ 18.965176] handle_irq_event+0x48/0x78 [ 18.969612] handle_fasteoi_irq+0xac/0x160 [ 18.974058] generic_handle_irq+0x24/0x38 [ 18.978501] __handle_domain_irq+0x60/0xb8 [ 18.982938] gic_handle_irq+0x50/0xa0 [ 18.987351] el1_irq+0xb4/0x130 [ 18.991734] debug_lockdep_rcu_enabled+0x2c/0x30 [ 18.996180] schedule+0x38/0xa0 [ 19.000609] schedule_timeout+0x3a8/0x510 [ 19.005064] wait_for_common+0x15c/0x180 [ 19.009513] wait_for_completion+0x14/0x20 [ 19.013951] mmc_wait_for_req_done+0x28/0x168 [ 19.018402] mmc_wait_for_req+0xa8/0xe8 [ 19.022809] mmc_wait_for_cmd+0x64/0x98 [ 19.027177] mmc_io_rw_direct_host+0x94/0x130 [ 19.031563] mmc_io_rw_direct+0x10/0x18 [ 19.035922] sdio_enable_func+0xe8/0x1d0 [ 19.040294] btsdio_open+0x24/0xc0 [btsdio] [ 19.044742] hci_dev_do_open+0x64/0x598 [bluetooth] [ 19.049228] hci_power_on+0x50/0x270 [bluetooth] [ 19.053687] process_one_work+0x2a0/0x6e0 [ 19.058143] worker_thread+0x40/0x448 [ 19.062608] kthread+0x12c/0x130 [ 19.067064] ret_from_fork+0x10/0x1c [ 19.071513] irq event stamp: 12 [ 19.075937] hardirqs last enabled at (11): [] _raw_spin_unlock_irq+0x2c/0x60 [ 19.083560] hardirqs last disabled at (12): [] __schedule+0xc4/0xa60 [ 19.091401] softirqs last enabled at (0): [] copy_process.isra.4.part.5+0x4d8/0x1c50 [ 19.100801] softirqs last disabled at (0): [<0000000000000000>] (null) [ 19.108135] ---[ end trace 38c4920787b88c75 ]--- So, fix this by enabling the fast_io option in our regmap config so that regmap uses spinlocks for locking instead of mutexes. Signed-off-by: Lyude Paul Fixes: 3f68be7d8e96 ("drm/meson: Add support for HDMI encoder and DW-HDMI bridge + PHY") Cc: Daniel Vetter Cc: Neil Armstrong Cc: Carlo Caione Cc: Kevin Hilman Cc: dri-devel@lists.freedesktop.org Cc: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: # v4.12+ Acked-by: Neil Armstrong Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20181124191238.28276-1-lyude@redhat.com Signed-off-by: Sean Paul --- drivers/gpu/drm/meson/meson_dw_hdmi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c index df7247cd93f9..2cb2ad26d716 100644 --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c @@ -706,6 +706,7 @@ static const struct regmap_config meson_dw_hdmi_regmap_config = { .reg_read = meson_dw_hdmi_reg_read, .reg_write = meson_dw_hdmi_reg_write, .max_register = 0x10000, + .fast_io = true, }; static bool meson_hdmi_connector_is_available(struct device *dev) From 97b2a3180a559a33852ac0cd77904166069484fd Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Sat, 24 Nov 2018 20:21:17 -0500 Subject: [PATCH 5/7] drm/meson: Fix OOB memory accesses in meson_viu_set_osd_lut() Currently on driver bringup with KASAN enabled, meson triggers an OOB memory access as shown below: [ 117.904528] ================================================================== [ 117.904560] BUG: KASAN: global-out-of-bounds in meson_viu_set_osd_lut+0x7a0/0x890 [ 117.904588] Read of size 4 at addr ffff20000a63ce24 by task systemd-udevd/498 [ 117.904601] [ 118.083372] CPU: 4 PID: 498 Comm: systemd-udevd Not tainted 4.20.0-rc3Lyude-Test+ #20 [ 118.091143] Hardware name: amlogic khadas-vim2/khadas-vim2, BIOS 2018.07-rc2-armbian 09/11/2018 [ 118.099768] Call trace: [ 118.102181] dump_backtrace+0x0/0x3e8 [ 118.105796] show_stack+0x14/0x20 [ 118.109083] dump_stack+0x130/0x1c4 [ 118.112539] print_address_description+0x60/0x25c [ 118.117214] kasan_report+0x1b4/0x368 [ 118.120851] __asan_report_load4_noabort+0x18/0x20 [ 118.125566] meson_viu_set_osd_lut+0x7a0/0x890 [ 118.129953] meson_viu_init+0x10c/0x290 [ 118.133741] meson_drv_bind_master+0x474/0x748 [ 118.138141] meson_drv_bind+0x10/0x18 [ 118.141760] try_to_bring_up_master+0x3d8/0x768 [ 118.146249] component_add+0x214/0x570 [ 118.149978] meson_dw_hdmi_probe+0x18/0x20 [meson_dw_hdmi] [ 118.155404] platform_drv_probe+0x98/0x138 [ 118.159455] really_probe+0x2a0/0xa70 [ 118.163070] driver_probe_device+0x1b4/0x2d8 [ 118.167299] __driver_attach+0x200/0x280 [ 118.171189] bus_for_each_dev+0x10c/0x1a8 [ 118.175144] driver_attach+0x38/0x50 [ 118.178681] bus_add_driver+0x330/0x608 [ 118.182471] driver_register+0x140/0x388 [ 118.186361] __platform_driver_register+0xc8/0x108 [ 118.191117] meson_dw_hdmi_platform_driver_init+0x1c/0x1000 [meson_dw_hdmi] [ 118.198022] do_one_initcall+0x12c/0x3bc [ 118.201883] do_init_module+0x1fc/0x638 [ 118.205673] load_module+0x4b4c/0x6808 [ 118.209387] __se_sys_init_module+0x2e8/0x3c0 [ 118.213699] __arm64_sys_init_module+0x68/0x98 [ 118.218100] el0_svc_common+0x104/0x210 [ 118.221893] el0_svc_handler+0x48/0xb8 [ 118.225594] el0_svc+0x8/0xc [ 118.228429] [ 118.229887] The buggy address belongs to the variable: [ 118.235007] eotf_33_linear_mapping+0x84/0xc0 [ 118.239301] [ 118.240752] Memory state around the buggy address: [ 118.245522] ffff20000a63cd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 118.252695] ffff20000a63cd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 118.259850] >ffff20000a63ce00: 00 00 00 00 04 fa fa fa fa fa fa fa 00 00 00 00 [ 118.267000] ^ [ 118.271222] ffff20000a63ce80: 00 fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 [ 118.278393] ffff20000a63cf00: 00 00 00 00 00 00 00 00 00 00 00 00 04 fa fa fa [ 118.285542] ================================================================== [ 118.292699] Disabling lock debugging due to kernel taint It seems that when looping through the OSD EOTF LUT maps, we use the same max iterator for OETF: 20. This is wrong though, since 20*2 is 40, which means that we'll stop out of bounds on the EOTF maps. But, this whole thing is already confusing enough to read through as-is, so let's just replace all of the hardcoded sizes with OSD_(OETF/EOTF)_LUT_SIZE / 2. Signed-off-by: Lyude Paul Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller") Cc: Neil Armstrong Cc: Maxime Ripard Cc: Carlo Caione Cc: Kevin Hilman Cc: dri-devel@lists.freedesktop.org Cc: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: # v4.10+ Acked-by: Neil Armstrong Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20181125012117.31915-1-lyude@redhat.com Signed-off-by: Sean Paul --- drivers/gpu/drm/meson/meson_viu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/meson/meson_viu.c b/drivers/gpu/drm/meson/meson_viu.c index 6bcfa527c180..26a0857878bf 100644 --- a/drivers/gpu/drm/meson/meson_viu.c +++ b/drivers/gpu/drm/meson/meson_viu.c @@ -184,18 +184,18 @@ void meson_viu_set_osd_lut(struct meson_drm *priv, enum viu_lut_sel_e lut_sel, if (lut_sel == VIU_LUT_OSD_OETF) { writel(0, priv->io_base + _REG(addr_port)); - for (i = 0; i < 20; i++) + for (i = 0; i < (OSD_OETF_LUT_SIZE / 2); i++) writel(r_map[i * 2] | (r_map[i * 2 + 1] << 16), priv->io_base + _REG(data_port)); writel(r_map[OSD_OETF_LUT_SIZE - 1] | (g_map[0] << 16), priv->io_base + _REG(data_port)); - for (i = 0; i < 20; i++) + for (i = 0; i < (OSD_OETF_LUT_SIZE / 2); i++) writel(g_map[i * 2 + 1] | (g_map[i * 2 + 2] << 16), priv->io_base + _REG(data_port)); - for (i = 0; i < 20; i++) + for (i = 0; i < (OSD_OETF_LUT_SIZE / 2); i++) writel(b_map[i * 2] | (b_map[i * 2 + 1] << 16), priv->io_base + _REG(data_port)); @@ -211,18 +211,18 @@ void meson_viu_set_osd_lut(struct meson_drm *priv, enum viu_lut_sel_e lut_sel, } else if (lut_sel == VIU_LUT_OSD_EOTF) { writel(0, priv->io_base + _REG(addr_port)); - for (i = 0; i < 20; i++) + for (i = 0; i < (OSD_EOTF_LUT_SIZE / 2); i++) writel(r_map[i * 2] | (r_map[i * 2 + 1] << 16), priv->io_base + _REG(data_port)); writel(r_map[OSD_EOTF_LUT_SIZE - 1] | (g_map[0] << 16), priv->io_base + _REG(data_port)); - for (i = 0; i < 20; i++) + for (i = 0; i < (OSD_EOTF_LUT_SIZE / 2); i++) writel(g_map[i * 2 + 1] | (g_map[i * 2 + 2] << 16), priv->io_base + _REG(data_port)); - for (i = 0; i < 20; i++) + for (i = 0; i < (OSD_EOTF_LUT_SIZE / 2); i++) writel(b_map[i * 2] | (b_map[i * 2 + 1] << 16), priv->io_base + _REG(data_port)); From 31e1ab494559fb46de304cc6c2aed1528f94b298 Mon Sep 17 00:00:00 2001 From: Christian Hewitt Date: Wed, 21 Nov 2018 13:39:29 +0400 Subject: [PATCH 6/7] drm/meson: add support for 1080p25 mode This essential mode for PAL users is missing, so add it. Fixes: 335e3713afb87 ("drm/meson: Add support for HDMI venc modes and settings") Signed-off-by: Christian Hewitt Acked-by: Neil Armstrong Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/1542793169-13008-1-git-send-email-christianshewitt@gmail.com Signed-off-by: Sean Paul --- drivers/gpu/drm/meson/meson_venc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/meson/meson_venc.c b/drivers/gpu/drm/meson/meson_venc.c index 2f9c3814a290..be76f3d64bf2 100644 --- a/drivers/gpu/drm/meson/meson_venc.c +++ b/drivers/gpu/drm/meson/meson_venc.c @@ -715,6 +715,7 @@ struct meson_hdmi_venc_vic_mode { { 5, &meson_hdmi_encp_mode_1080i60 }, { 20, &meson_hdmi_encp_mode_1080i50 }, { 32, &meson_hdmi_encp_mode_1080p24 }, + { 33, &meson_hdmi_encp_mode_1080p50 }, { 34, &meson_hdmi_encp_mode_1080p30 }, { 31, &meson_hdmi_encp_mode_1080p50 }, { 16, &meson_hdmi_encp_mode_1080p60 }, From 9765635b30756eb74e05e260ac812659c296cd28 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Wed, 28 Nov 2018 16:00:05 -0500 Subject: [PATCH 7/7] Revert "drm/dp_mst: Skip validating ports during destruction, just ref" This reverts commit: c54c7374ff44 ("drm/dp_mst: Skip validating ports during destruction, just ref") ugh. In drm_dp_destroy_connector_work(), we have a pretty good chance of freeing the actual struct drm_dp_mst_port. However, after destroying things we send a hotplug through (*mgr->cbs->hotplug)(mgr) which is where the problems start. For i915, this calls all the way down to the fbcon probing helpers, which start trying to access the port in a modeset. [ 45.062001] ================================================================== [ 45.062112] BUG: KASAN: use-after-free in ex_handler_refcount+0x146/0x180 [ 45.062196] Write of size 4 at addr ffff8882b4b70968 by task kworker/3:1/53 [ 45.062325] CPU: 3 PID: 53 Comm: kworker/3:1 Kdump: loaded Tainted: G O 4.20.0-rc4Lyude-Test+ #3 [ 45.062442] Hardware name: LENOVO 20BWS1KY00/20BWS1KY00, BIOS JBET71WW (1.35 ) 09/14/2018 [ 45.062554] Workqueue: events drm_dp_destroy_connector_work [drm_kms_helper] [ 45.062641] Call Trace: [ 45.062685] dump_stack+0xbd/0x15a [ 45.062735] ? dump_stack_print_info.cold.0+0x1b/0x1b [ 45.062801] ? printk+0x9f/0xc5 [ 45.062847] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 45.062909] ? ex_handler_refcount+0x146/0x180 [ 45.062970] print_address_description+0x71/0x239 [ 45.063036] ? ex_handler_refcount+0x146/0x180 [ 45.063095] kasan_report.cold.5+0x242/0x30b [ 45.063155] __asan_report_store4_noabort+0x1c/0x20 [ 45.063313] ex_handler_refcount+0x146/0x180 [ 45.063371] ? ex_handler_clear_fs+0xb0/0xb0 [ 45.063428] fixup_exception+0x98/0xd7 [ 45.063484] ? raw_notifier_call_chain+0x20/0x20 [ 45.063548] do_trap+0x6d/0x210 [ 45.063605] ? _GLOBAL__sub_I_65535_1_drm_dp_aux_unregister_devnode+0x2f/0x1c6 [drm_kms_helper] [ 45.063732] do_error_trap+0xc0/0x170 [ 45.063802] ? _GLOBAL__sub_I_65535_1_drm_dp_aux_unregister_devnode+0x2f/0x1c6 [drm_kms_helper] [ 45.063929] do_invalid_op+0x3b/0x50 [ 45.063997] ? _GLOBAL__sub_I_65535_1_drm_dp_aux_unregister_devnode+0x2f/0x1c6 [drm_kms_helper] [ 45.064103] invalid_op+0x14/0x20 [ 45.064162] RIP: 0010:_GLOBAL__sub_I_65535_1_drm_dp_aux_unregister_devnode+0x2f/0x1c6 [drm_kms_helper] [ 45.064274] Code: 00 48 c7 c7 80 fe 53 a0 48 89 e5 e8 5b 6f 26 e1 5d c3 48 8d 0e 0f 0b 48 8d 0b 0f 0b 48 8d 0f 0f 0b 48 8d 0f 0f 0b 49 8d 4d 00 <0f> 0b 49 8d 0e 0f 0b 48 8d 08 0f 0b 49 8d 4d 00 0f 0b 48 8d 0b 0f [ 45.064569] RSP: 0018:ffff8882b789ee10 EFLAGS: 00010282 [ 45.064637] RAX: ffff8882af47ae70 RBX: ffff8882af47aa60 RCX: ffff8882b4b70968 [ 45.064723] RDX: ffff8882af47ae70 RSI: 0000000000000008 RDI: ffff8882b788bdb8 [ 45.064808] RBP: ffff8882b789ee28 R08: ffffed1056f13db4 R09: ffffed1056f13db3 [ 45.064894] R10: ffffed1056f13db3 R11: ffff8882b789ed9f R12: ffff8882af47ad28 [ 45.064980] R13: ffff8882b4b70968 R14: ffff8882acd86728 R15: ffff8882b4b75dc8 [ 45.065084] drm_dp_mst_reset_vcpi_slots+0x12/0x80 [drm_kms_helper] [ 45.065225] intel_mst_disable_dp+0xda/0x180 [i915] [ 45.065361] intel_encoders_disable.isra.107+0x197/0x310 [i915] [ 45.065498] haswell_crtc_disable+0xbe/0x400 [i915] [ 45.065622] ? i9xx_disable_plane+0x1c0/0x3e0 [i915] [ 45.065750] intel_atomic_commit_tail+0x74e/0x3e60 [i915] [ 45.065884] ? intel_pre_plane_update+0xbc0/0xbc0 [i915] [ 45.065968] ? drm_atomic_helper_swap_state+0x88b/0x1d90 [drm_kms_helper] [ 45.066054] ? kasan_check_write+0x14/0x20 [ 45.066165] ? i915_gem_track_fb+0x13a/0x330 [i915] [ 45.066277] ? i915_sw_fence_complete+0xe9/0x140 [i915] [ 45.066406] ? __i915_sw_fence_complete+0xc50/0xc50 [i915] [ 45.066540] intel_atomic_commit+0x72e/0xef0 [i915] [ 45.066635] ? drm_dev_dbg+0x200/0x200 [drm] [ 45.066764] ? intel_atomic_commit_tail+0x3e60/0x3e60 [i915] [ 45.066898] ? intel_atomic_commit_tail+0x3e60/0x3e60 [i915] [ 45.067001] drm_atomic_commit+0xc4/0xf0 [drm] [ 45.067074] restore_fbdev_mode_atomic+0x562/0x780 [drm_kms_helper] [ 45.067166] ? drm_fb_helper_debug_leave+0x690/0x690 [drm_kms_helper] [ 45.067249] ? kasan_check_read+0x11/0x20 [ 45.067324] restore_fbdev_mode+0x127/0x4b0 [drm_kms_helper] [ 45.067364] ? kasan_check_read+0x11/0x20 [ 45.067406] drm_fb_helper_restore_fbdev_mode_unlocked+0x164/0x200 [drm_kms_helper] [ 45.067462] ? drm_fb_helper_hotplug_event+0x30/0x30 [drm_kms_helper] [ 45.067508] ? kasan_check_write+0x14/0x20 [ 45.070360] ? mutex_unlock+0x22/0x40 [ 45.073748] drm_fb_helper_set_par+0xb2/0xf0 [drm_kms_helper] [ 45.075846] drm_fb_helper_hotplug_event.part.33+0x1cd/0x290 [drm_kms_helper] [ 45.078088] drm_fb_helper_hotplug_event+0x1c/0x30 [drm_kms_helper] [ 45.082614] intel_fbdev_output_poll_changed+0x9f/0x140 [i915] [ 45.087069] drm_kms_helper_hotplug_event+0x67/0x90 [drm_kms_helper] [ 45.089319] intel_dp_mst_hotplug+0x37/0x50 [i915] [ 45.091496] drm_dp_destroy_connector_work+0x510/0x6f0 [drm_kms_helper] [ 45.093675] ? drm_dp_update_payload_part1+0x1220/0x1220 [drm_kms_helper] [ 45.095851] ? kasan_check_write+0x14/0x20 [ 45.098473] ? kasan_check_read+0x11/0x20 [ 45.101155] ? strscpy+0x17c/0x530 [ 45.103808] ? __switch_to_asm+0x34/0x70 [ 45.106456] ? syscall_return_via_sysret+0xf/0x7f [ 45.109711] ? read_word_at_a_time+0x20/0x20 [ 45.113138] ? __switch_to_asm+0x40/0x70 [ 45.116529] ? __switch_to_asm+0x34/0x70 [ 45.119891] ? __switch_to_asm+0x40/0x70 [ 45.123224] ? __switch_to_asm+0x34/0x70 [ 45.126540] ? __switch_to_asm+0x34/0x70 [ 45.129824] process_one_work+0x88d/0x15d0 [ 45.133172] ? pool_mayday_timeout+0x850/0x850 [ 45.136459] ? pci_mmcfg_check_reserved+0x110/0x128 [ 45.139739] ? wake_q_add+0xb0/0xb0 [ 45.143010] ? check_preempt_wakeup+0x652/0x1050 [ 45.146304] ? worker_enter_idle+0x29e/0x740 [ 45.149589] ? __schedule+0x1ec0/0x1ec0 [ 45.152937] ? kasan_check_read+0x11/0x20 [ 45.156179] ? _raw_spin_lock_irq+0xa3/0x130 [ 45.159382] ? _raw_read_unlock_irqrestore+0x30/0x30 [ 45.162542] ? kasan_check_write+0x14/0x20 [ 45.165657] worker_thread+0x1a5/0x1470 [ 45.168725] ? set_load_weight+0x2e0/0x2e0 [ 45.171755] ? process_one_work+0x15d0/0x15d0 [ 45.174806] ? __switch_to_asm+0x34/0x70 [ 45.177645] ? __switch_to_asm+0x40/0x70 [ 45.180323] ? __switch_to_asm+0x34/0x70 [ 45.182936] ? __switch_to_asm+0x40/0x70 [ 45.185539] ? __switch_to_asm+0x34/0x70 [ 45.188100] ? __switch_to_asm+0x40/0x70 [ 45.190628] ? __schedule+0x7d4/0x1ec0 [ 45.193143] ? save_stack+0xa9/0xd0 [ 45.195632] ? kasan_check_write+0x10/0x20 [ 45.198162] ? kasan_kmalloc+0xc4/0xe0 [ 45.200609] ? kmem_cache_alloc_trace+0xdd/0x190 [ 45.203046] ? kthread+0x9f/0x3b0 [ 45.205470] ? ret_from_fork+0x35/0x40 [ 45.207876] ? unwind_next_frame+0x43/0x50 [ 45.210273] ? __save_stack_trace+0x82/0x100 [ 45.212658] ? deactivate_slab.isra.67+0x3d4/0x580 [ 45.215026] ? default_wake_function+0x35/0x50 [ 45.217399] ? kasan_check_read+0x11/0x20 [ 45.219825] ? _raw_spin_lock_irqsave+0xae/0x140 [ 45.222174] ? __lock_text_start+0x8/0x8 [ 45.224521] ? replenish_dl_entity.cold.62+0x4f/0x4f [ 45.226868] ? __kthread_parkme+0x87/0xf0 [ 45.229200] kthread+0x2f7/0x3b0 [ 45.231557] ? process_one_work+0x15d0/0x15d0 [ 45.233923] ? kthread_park+0x120/0x120 [ 45.236249] ret_from_fork+0x35/0x40 [ 45.240875] Allocated by task 242: [ 45.243136] save_stack+0x43/0xd0 [ 45.245385] kasan_kmalloc+0xc4/0xe0 [ 45.247597] kmem_cache_alloc_trace+0xdd/0x190 [ 45.249793] drm_dp_add_port+0x1e0/0x2170 [drm_kms_helper] [ 45.252000] drm_dp_send_link_address+0x4a7/0x740 [drm_kms_helper] [ 45.254389] drm_dp_check_and_send_link_address+0x1a7/0x210 [drm_kms_helper] [ 45.256803] drm_dp_mst_link_probe_work+0x6f/0xb0 [drm_kms_helper] [ 45.259200] process_one_work+0x88d/0x15d0 [ 45.261597] worker_thread+0x1a5/0x1470 [ 45.264038] kthread+0x2f7/0x3b0 [ 45.266371] ret_from_fork+0x35/0x40 [ 45.270937] Freed by task 53: [ 45.273170] save_stack+0x43/0xd0 [ 45.275382] __kasan_slab_free+0x139/0x190 [ 45.277604] kasan_slab_free+0xe/0x10 [ 45.279826] kfree+0x99/0x1b0 [ 45.282044] drm_dp_free_mst_port+0x4a/0x60 [drm_kms_helper] [ 45.284330] drm_dp_destroy_connector_work+0x43e/0x6f0 [drm_kms_helper] [ 45.286660] process_one_work+0x88d/0x15d0 [ 45.288934] worker_thread+0x1a5/0x1470 [ 45.291231] kthread+0x2f7/0x3b0 [ 45.293547] ret_from_fork+0x35/0x40 [ 45.298206] The buggy address belongs to the object at ffff8882b4b70968 which belongs to the cache kmalloc-2k of size 2048 [ 45.303047] The buggy address is located 0 bytes inside of 2048-byte region [ffff8882b4b70968, ffff8882b4b71168) [ 45.308010] The buggy address belongs to the page: [ 45.310477] page:ffffea000ad2dc00 count:1 mapcount:0 mapping:ffff8882c080cf40 index:0x0 compound_mapcount: 0 [ 45.313051] flags: 0x8000000000010200(slab|head) [ 45.315635] raw: 8000000000010200 ffffea000aac2808 ffffea000abe8608 ffff8882c080cf40 [ 45.318300] raw: 0000000000000000 00000000000d000d 00000001ffffffff 0000000000000000 [ 45.320966] page dumped because: kasan: bad access detected [ 45.326312] Memory state around the buggy address: [ 45.329085] ffff8882b4b70800: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 45.331845] ffff8882b4b70880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 45.334584] >ffff8882b4b70900: fc fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb [ 45.337302] ^ [ 45.340061] ffff8882b4b70980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.342910] ffff8882b4b70a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 45.345748] ================================================================== So, this definitely isn't a fix that we want. This being said; there's no real easy fix for this problem because of some of the catch-22's of the MST helpers current design. For starters; we always need to validate a port with drm_dp_get_validated_port_ref(), but validation relies on the lifetime of the port in the actual topology. So once the port is gone, it can't be validated again. If we were to try to make the payload helpers not use port validation, then we'd cause another problem: if the port isn't validated, it could be freed and we'd just start causing more KASAN issues. There are already hacks that attempt to workaround this in drm_dp_mst_destroy_connector_work() by re-initializing the kref so that it can be used again and it's memory can be freed once the VCPI helpers finish removing the port's respective payloads. But none of these really do anything helpful since the port still can't be validated since it's gone from the topology. Also, that workaround is immensely confusing to read through. What really needs to be done in order to fix this is to teach DRM how to track the lifetime of the structs for MST ports and branch devices separately from their lifetime in the actual topology. Simply put; this means having two different krefs-one that removes the port/branch device from the topology, and one that finally calls kfree(). This would let us simplify things, since we'd now be able to keep ports around without having to keep them in the topology at the same time, which is exactly what we need in order to teach our VCPI helpers to only validate ports when it's actually necessary without running the risk of trying to use unallocated memory. Such a fix is on it's way, but for now let's play it safe and just revert this. If this bug has been around for well over a year, we can wait a little while to get an actual proper fix here. Signed-off-by: Lyude Paul Fixes: c54c7374ff44 ("drm/dp_mst: Skip validating ports during destruction, just ref") Cc: Daniel Vetter Cc: Sean Paul Cc: Jerry Zuo Cc: Harry Wentland Cc: stable@vger.kernel.org # v4.6+ Acked-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20181128210005.24434-1-lyude@redhat.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 250d7160826f..0e0df398222d 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -1023,20 +1023,9 @@ static struct drm_dp_mst_port *drm_dp_mst_get_port_ref_locked(struct drm_dp_mst_ static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port) { struct drm_dp_mst_port *rport = NULL; - mutex_lock(&mgr->lock); - /* - * Port may or may not be 'valid' but we don't care about that when - * destroying the port and we are guaranteed that the port pointer - * will be valid until we've finished - */ - if (current_work() == &mgr->destroy_connector_work) { - kref_get(&port->kref); - rport = port; - } else if (mgr->mst_primary) { - rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, - port); - } + if (mgr->mst_primary) + rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port); mutex_unlock(&mgr->lock); return rport; }