[Freedreno] gpu: msm: possible circular locking dependency detected on 5.5

[Fabio Estevam]

Hi,

Here is an adreno regression I noticed on imx53 running 5.5.13:

[   21.283902] ======================================================
[   21.290148] WARNING: possible circular locking dependency detected
[   21.296409] 5.5.13 #1 Not tainted
[   21.299785] ------------------------------------------------------
[   21.306030] kworker/u2:1/19 is trying to acquire lock:
[   21.311236] dc888ae8 (reservation_ww_class_mutex){+.+.}, at:
dma_buf_detach+0x78/0x1e0
[   21.319341]
[   21.319341] but task is already holding lock:
[   21.325232] dc88838c (&msm_obj->lock){+.+.}, at:
msm_gem_free_work+0x100/0x188
[   21.332587]
[   21.33258[   32.525073] evbug: Event. Dev: input1, Type: 3, Code:
1, Value: 41
[   32.531942] evbug: Event. Dev: input1, Type: 0, Code: 0, Value: 0
7] which lock already depends on the new lock.
[   21.332587]
[   21.340823]
[   21.340823] the existing dependency chain (in reverse order) is:
[   21.348362]
[   21.348362] -> #1 (&msm_obj->lock){+.+.}:
[   21.353989]        mutex_lock_nested+0x1c/0x24
[   21.358514]        msm_gem_get_and_pin_iova+0x30/0x158
[   21.363733]        msm_ioctl_gem_submit+0xa90/0x1148
[   21.368775]        drm_ioctl_kernel+0xa4/0xec
[   21.373203]        drm_ioctl+0x1e0/0x3c8
[   21.377215]        do_vfs_ioctl+0x9c/0xa68
[   21.381388]        ksys_ioctl+0x34/0x60
[   21.385304]        ret_fast_syscall+0x0/0x28
[   21.389646]        0xbea6f8d8
[   21.392670]
[   21.392670] -> #0 (reservation_ww_class_mutex){+.+.}:
[   21.399333]        lock_acquire+0xcc/0x1ec
[   21.403516]        __ww_mutex_lock.constprop.8+0x94/0x10a4
[   21.409080]        ww_mutex_lock+0x78/0xb0
[   21.413261]        dma_buf_detach+0x78/0x1e0
[   21.417637]        drm_prime_gem_destroy+0x2c/0x38
[   21.422505]        msm_gem_free_work+0x88/0x188
[   21.427133]        process_one_work+0x2c4/0x754
[   21.431744]        worker_thread+0x2c/0x590
[   21.436015]        kthread+0x134/0x148
[   21.439838]        ret_from_fork+0x14/0x20
[   21.444000]        0x0
[   21.446418]
[   21.446418] other info that might help us debug this:
[   21.446418]
[   21.454483]  Possible unsafe locking scenario:
[   21.454483]
[   21.460460]        CPU0                    CPU1
[   21.465044]        ----                    ----
[   21.469627]   lock(&msm_obj->lock);
[   21.473190]                                lock(reservation_ww_class_mutex);
[   21.480314]                                lock(&msm_obj->lock);
[   21.486392]   lock(reservation_ww_class_mutex);
[   21.490996]
[   21.490996]  *** DEADLOCK ***
[   21.490996]
[   21.496985] 4 locks held by kworker/u2:1/19:
[   21.501311]  #0: dc43a6a0 ((wq_completion)msm){+.+.}, at:
process_one_work+0x210/0x754
[   21.509358]  #1: dc207f1c
((work_completion)(&priv->free_work)){+.+.}, at:
process_one_work+0x210/0x754
[   21.518876]  #2: dc3a7070 (&dev->struct_mutex){+.+.}, at:
msm_gem_free_work+0x4c/0x188
[   21.526915]  #3: dc88838c (&msm_obj->lock){+.+.}, at:
msm_gem_free_work+0x100/0x188
[   21.534692]
[   21.534692] stack backtrace:
[   21.539136] CPU: 0 PID: 19 Comm: kworker/u2:1 Not tainted 5.5.13 #1
[   21.545470] Hardware name: Freescale i.MX53 (Device Tree Support)
[   21.551667] Workqueue: msm msm_gem_free_work
[   21.556087] [<c0112e18>] (unwind_backtrace) from [<c010cda0>]
(show_stack+0x10/0x14)
[   21.563950] [<c010cda0>] (show_stack) from [<c0c9989c>]
(dump_stack+0xe4/0x11c)
[   21.571372] [<c0c9989c>] (dump_stack) from [<c0180334>]
(check_noncircular+0x130/0x1e4)
[   21.579486] [<c0180334>] (check_noncircular) from [<c0182450>]
(__lock_acquire+0xf58/0x2458)
[   21.588030] [<c0182450>] (__lock_acquire) from [<c01841bc>]
(lock_acquire+0xcc/0x1ec)
[   21.595976] [<c01841bc>] (lock_acquire) from [<c0cb887c>]
(__ww_mutex_lock.constprop.8+0x94/0x10a4)
[   21.605134] [<c0cb887c>] (__ww_mutex_lock.constprop.8) from
[<c0cb99b4>] (ww_mutex_lock+0x78/0xb0)
[   21.614207] [<c0cb99b4>] (ww_mutex_lock) from [<c070c078>]
(dma_buf_detach+0x78/0x1e0)
[   21.622239] [<c070c078>] (dma_buf_detach) from [<c06276e8>]
(drm_prime_gem_destroy+0x2c/0x38)
[   21.630874] [<c06276e8>] (drm_prime_gem_destroy) from [<c0696b48>]
(msm_gem_free_work+0x88/0x188)
[   21.639854] [<c0696b48>] (msm_gem_free_work) from [<c0148228>]
(process_one_work+0x2c4/0x754)
[   21.648487] [<c0148228>] (process_one_work) from [<c01486e4>]
(worker_thread+0x2c/0x590)
[   21.656681] [<c01486e4>] (worker_thread) from [<c01505f0>]
(kthread+0x134/0x148)
[   21.664176] [<c01505f0>] (kthread) from [<c01010b4>]
(ret_from_fork+0x14/0x20)
[   21.671470] Exception stack(0xdc207fb0 to 0xdc207ff8)

In order to reproduce it, I just launch kmscube and it starts running normally.

Then I do a "CTRL + C" and the message below appears.

Testing on 5.4.x I don't see this problem.

I haven't started bisecting this yet, but just checking if anyone has
any ideas first.

Thanks,

Fabio Estevam