Seen on eve with chromeos-4.12 after enabling lockdebug.

[  139.802542] ======================================================
[  139.809465] WARNING: possible circular locking dependency detected
[  139.816391] 4.12.14 #14 Not tainted
[  139.820303] ------------------------------------------------------
[  139.827230] wayland-service/2671 is trying to acquire lock:
[  139.833472]  (&(&array->lock)->rlock){......}, at: [<ffffffff94d4e5a9>] dma_fence_signal+0x93/0x14d
[  139.843627]
               but task is already holding lock:
[  139.850166]  (&(&obj->child_list_lock)->rlock){......}, at: [<ffffffff94d51862>] sw_sync_ioctl+0x3db/0x505
[  139.860992]
               which lock already depends on the new lock.
[  139.870147]
               the existing dependency chain (in reverse order) is:
[  139.878530]
               -> #1 (&(&obj->child_list_lock)->rlock){......}:
[  139.886546]        lock_acquire+0x1e1/0x217
[  139.891243]        _raw_spin_lock_irqsave+0x3a/0x4e
[  139.896719]        dma_fence_add_callback+0x89/0x182
[  139.902292]        dma_fence_array_enable_signaling+0xad/0xec
[  139.908739]        dma_fence_add_callback+0xdd/0x182
[  139.914311]        sync_file_poll+0x93/0xc8
[  139.919013]        do_sys_poll+0x386/0x68b
[  139.923616]        SyS_ppoll+0x10b/0x1a4
[  139.928023]        entry_SYSCALL_64_fastpath+0x2c/0xc1
[  139.933779]
               -> #0 (&(&array->lock)->rlock){......}:
[  139.940921]        __lock_acquire+0x1269/0x15be
[  139.946010]        lock_acquire+0x1e1/0x217
[  139.950711]        _raw_spin_lock_irqsave+0x3a/0x4e
[  139.956188]        dma_fence_signal+0x93/0x14d
[  139.961177]        dma_fence_array_cb_func+0x46/0x4b
[  139.966747]        dma_fence_signal_locked+0x11f/0x149
[  139.972507]        sw_sync_ioctl+0x46a/0x505
[  139.977299]        vfs_ioctl+0x4b/0x5d
[  139.981511]        do_vfs_ioctl+0x643/0x666
[  139.986208]        SyS_ioctl+0x57/0x79
[  139.990421]        entry_SYSCALL_64_fastpath+0x2c/0xc1
[  139.996176]

Complete dmesg log is attached.

Related upstream discussion: https://patchwork.freedesktop.org/patch/119844/

 

Deleted: dmesg.wayland.170920 58.3 KB

dmesg.wayland.170920 58.3 KB Download