From: Stephen Boyd <swboyd@chromium.org> To: Rob Clark <robdclark@gmail.com> Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Krishna Manikandan <mkrishn@codeaurora.org> Subject: [PATCH] drm/msm/kms: Make a lock_class_key for each crtc mutex Date: Mon, 25 Jan 2021 18:01:13 -0800 [thread overview] Message-ID: <20210126020117.2753615-1-swboyd@chromium.org> (raw) Lockdep complains about an AA deadlock when rebooting the device. ============================================ WARNING: possible recursive locking detected 5.4.91 #1 Not tainted -------------------------------------------- reboot/5213 is trying to acquire lock: ffffff80d13391b0 (&kms->commit_lock[i]){+.+.}, at: lock_crtcs+0x60/0xa4 but task is already holding lock: ffffff80d1339110 (&kms->commit_lock[i]){+.+.}, at: lock_crtcs+0x60/0xa4 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&kms->commit_lock[i]); lock(&kms->commit_lock[i]); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by reboot/5213: __arm64_sys_reboot+0x148/0x2a0 device_shutdown+0x10c/0x2c4 drm_atomic_helper_shutdown+0x48/0xfc modeset_lock+0x120/0x24c lock_crtcs+0x60/0xa4 stack backtrace: CPU: 4 PID: 5213 Comm: reboot Not tainted 5.4.91 #1 Hardware name: Google Pompom (rev1) with LTE (DT) Call trace: dump_backtrace+0x0/0x1dc show_stack+0x24/0x30 dump_stack+0xfc/0x1a8 __lock_acquire+0xcd0/0x22b8 lock_acquire+0x1ec/0x240 __mutex_lock_common+0xe0/0xc84 mutex_lock_nested+0x48/0x58 lock_crtcs+0x60/0xa4 msm_atomic_commit_tail+0x348/0x570 commit_tail+0xdc/0x178 drm_atomic_helper_commit+0x160/0x168 drm_atomic_commit+0x68/0x80 This is because lockdep thinks all the locks taken in lock_crtcs() are the same lock, when they actually aren't. That's because we call mutex_init() in msm_kms_init() and that assigns on static key for every lock initialized in this loop. Let's allocate a dynamic number of lock_class_keys and assign them to each lock so that lockdep can figure out an AA deadlock isn't possible here. Fixes: b3d91800d9ac ("drm/msm: Fix race condition in msm driver with async layer updates") Cc: Krishna Manikandan <mkrishn@codeaurora.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> --- drivers/gpu/drm/msm/msm_kms.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h index d8151a89e163..4735251a394d 100644 --- a/drivers/gpu/drm/msm/msm_kms.h +++ b/drivers/gpu/drm/msm/msm_kms.h @@ -157,6 +157,7 @@ struct msm_kms { * from the crtc's pending_timer close to end of the frame: */ struct mutex commit_lock[MAX_CRTCS]; + struct lock_class_key commit_lock_keys[MAX_CRTCS]; unsigned pending_crtc_mask; struct msm_pending_timer pending_timers[MAX_CRTCS]; }; @@ -166,8 +167,11 @@ static inline int msm_kms_init(struct msm_kms *kms, { unsigned i, ret; - for (i = 0; i < ARRAY_SIZE(kms->commit_lock); i++) - mutex_init(&kms->commit_lock[i]); + for (i = 0; i < ARRAY_SIZE(kms->commit_lock); i++) { + lockdep_register_key(&kms->commit_lock_keys[i]); + __mutex_init(&kms->commit_lock[i], "&kms->commit_lock[i]", + &kms->commit_lock_keys[i]); + } kms->funcs = funcs; base-commit: 19c329f6808995b142b3966301f217c831e7cf31 -- https://chromeos.dev
WARNING: multiple messages have this Message-ID (diff)
From: Stephen Boyd <swboyd@chromium.org> To: Rob Clark <robdclark@gmail.com> Cc: linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Krishna Manikandan <mkrishn@codeaurora.org> Subject: [PATCH] drm/msm/kms: Make a lock_class_key for each crtc mutex Date: Mon, 25 Jan 2021 18:01:13 -0800 [thread overview] Message-ID: <20210126020117.2753615-1-swboyd@chromium.org> (raw) Lockdep complains about an AA deadlock when rebooting the device. ============================================ WARNING: possible recursive locking detected 5.4.91 #1 Not tainted -------------------------------------------- reboot/5213 is trying to acquire lock: ffffff80d13391b0 (&kms->commit_lock[i]){+.+.}, at: lock_crtcs+0x60/0xa4 but task is already holding lock: ffffff80d1339110 (&kms->commit_lock[i]){+.+.}, at: lock_crtcs+0x60/0xa4 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&kms->commit_lock[i]); lock(&kms->commit_lock[i]); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by reboot/5213: __arm64_sys_reboot+0x148/0x2a0 device_shutdown+0x10c/0x2c4 drm_atomic_helper_shutdown+0x48/0xfc modeset_lock+0x120/0x24c lock_crtcs+0x60/0xa4 stack backtrace: CPU: 4 PID: 5213 Comm: reboot Not tainted 5.4.91 #1 Hardware name: Google Pompom (rev1) with LTE (DT) Call trace: dump_backtrace+0x0/0x1dc show_stack+0x24/0x30 dump_stack+0xfc/0x1a8 __lock_acquire+0xcd0/0x22b8 lock_acquire+0x1ec/0x240 __mutex_lock_common+0xe0/0xc84 mutex_lock_nested+0x48/0x58 lock_crtcs+0x60/0xa4 msm_atomic_commit_tail+0x348/0x570 commit_tail+0xdc/0x178 drm_atomic_helper_commit+0x160/0x168 drm_atomic_commit+0x68/0x80 This is because lockdep thinks all the locks taken in lock_crtcs() are the same lock, when they actually aren't. That's because we call mutex_init() in msm_kms_init() and that assigns on static key for every lock initialized in this loop. Let's allocate a dynamic number of lock_class_keys and assign them to each lock so that lockdep can figure out an AA deadlock isn't possible here. Fixes: b3d91800d9ac ("drm/msm: Fix race condition in msm driver with async layer updates") Cc: Krishna Manikandan <mkrishn@codeaurora.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> --- drivers/gpu/drm/msm/msm_kms.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h index d8151a89e163..4735251a394d 100644 --- a/drivers/gpu/drm/msm/msm_kms.h +++ b/drivers/gpu/drm/msm/msm_kms.h @@ -157,6 +157,7 @@ struct msm_kms { * from the crtc's pending_timer close to end of the frame: */ struct mutex commit_lock[MAX_CRTCS]; + struct lock_class_key commit_lock_keys[MAX_CRTCS]; unsigned pending_crtc_mask; struct msm_pending_timer pending_timers[MAX_CRTCS]; }; @@ -166,8 +167,11 @@ static inline int msm_kms_init(struct msm_kms *kms, { unsigned i, ret; - for (i = 0; i < ARRAY_SIZE(kms->commit_lock); i++) - mutex_init(&kms->commit_lock[i]); + for (i = 0; i < ARRAY_SIZE(kms->commit_lock); i++) { + lockdep_register_key(&kms->commit_lock_keys[i]); + __mutex_init(&kms->commit_lock[i], "&kms->commit_lock[i]", + &kms->commit_lock_keys[i]); + } kms->funcs = funcs; base-commit: 19c329f6808995b142b3966301f217c831e7cf31 -- https://chromeos.dev _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next reply other threads:[~2021-01-26 20:14 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-26 2:01 Stephen Boyd [this message] 2021-01-26 2:01 ` [PATCH] drm/msm/kms: Make a lock_class_key for each crtc mutex Stephen Boyd 2021-01-26 2:01 ` [PATCHv2 0/3] iio: Add a ChromeOS EC MKBP proximity driver Stephen Boyd 2021-01-26 2:01 ` [PATCH v2 1/3] platform/chrome: cros_ec: Add SW_FRONT_PROXIMITY MKBP define Stephen Boyd 2021-01-26 2:01 ` [PATCH v2 2/3] dt-bindings: iio: Add cros ec proximity yaml doc Stephen Boyd 2021-01-26 2:01 ` [PATCH v2 3/3] iio: proximity: Add a ChromeOS EC MKBP proximity driver Stephen Boyd -- strict thread matches above, loose matches on Subject: below -- 2021-01-25 23:49 [PATCH] drm/msm/kms: Make a lock_class_key for each crtc mutex Stephen Boyd 2021-01-25 23:49 ` Stephen Boyd 2021-01-28 16:39 ` Rob Clark 2021-01-28 16:39 ` Rob Clark 2021-02-02 15:46 ` Daniel Vetter 2021-02-02 15:46 ` Daniel Vetter 2021-02-02 16:51 ` Rob Clark 2021-02-02 16:51 ` Rob Clark 2021-02-03 10:10 ` Daniel Vetter 2021-02-03 10:10 ` Daniel Vetter 2021-02-03 17:29 ` Rob Clark 2021-02-03 17:29 ` Rob Clark 2021-02-03 21:58 ` Stephen Boyd 2021-02-03 21:58 ` Stephen Boyd 2021-02-03 22:11 ` Rob Clark 2021-02-03 22:11 ` Rob Clark 2021-02-04 15:17 ` Daniel Vetter 2021-02-04 15:17 ` Daniel Vetter
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210126020117.2753615-1-swboyd@chromium.org \ --to=swboyd@chromium.org \ --cc=dri-devel@lists.freedesktop.org \ --cc=freedreno@lists.freedesktop.org \ --cc=linux-arm-msm@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=mkrishn@codeaurora.org \ --cc=robdclark@gmail.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.