1. 22 Aug, 2022 1 commit
    • Javier Martinez Canillas's avatar
      drm/msm: Make .remove and .shutdown HW shutdown consistent · 0a58d2ae
      Javier Martinez Canillas authored
      Drivers' .remove and .shutdown callbacks are executed on different code
      paths. The former is called when a device is removed from the bus, while
      the latter is called at system shutdown time to quiesce the device.
      
      This means that some overlap exists between the two, because both have to
      take care of properly shutting down the hardware. But currently the logic
      used in these two callbacks isn't consistent in msm drivers, which could
      lead to kernel panic.
      
      For example, on .remove the component is deleted and its .unbind callback
      leads to the hardware being shutdown but only if the DRM device has been
      marked as registered.
      
      That check doesn't exist in the .shutdown logic and this can lead to the
      driver calling drm_atomic_helper_shutdown() for a DRM device that hasn't
      been properly initialized.
      
      A situation like this can happen if drivers for expected sub-devices fail
      to probe, since the .bind callback will never be executed. If that is the
      case, drm_atomic_helper_shutdown() will attempt to take mutexes that are
      only initialized if drm_mode_config_init() is called during a device bind.
      
      This bug was attempted to be fixed in commit 623f279c ("drm/msm: fix
      shutdown hook in case GPU components failed to bind"), but unfortunately
      it still happens in some cases as the one mentioned above, i.e:
      
        systemd-shutdown[1]: Powering off.
        kvm: exiting hardware virtualization
        platform wifi-firmware.0: Removing from iommu group 12
        platform video-firmware.0: Removing from iommu group 10
        ------------[ cut here ]------------
        WARNING: CPU: 6 PID: 1 at drivers/gpu/drm/drm_modeset_lock.c:317 drm_modeset_lock_all_ctx+0x3c4/0x3d0
        ...
        Hardware name: Google CoachZ (rev3+) (DT)
        pstate: a0400009 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
        pc : drm_modeset_lock_all_ctx+0x3c4/0x3d0
        lr : drm_modeset_lock_all_ctx+0x48/0x3d0
        sp : ffff80000805bb80
        x29: ffff80000805bb80 x28: ffff327c00128000 x27: 0000000000000000
        x26: 0000000000000000 x25: 0000000000000001 x24: ffffc95d820ec030
        x23: ffff327c00bbd090 x22: ffffc95d8215eca0 x21: ffff327c039c5800
        x20: ffff327c039c5988 x19: ffff80000805bbe8 x18: 0000000000000034
        x17: 000000040044ffff x16: ffffc95d80cac920 x15: 0000000000000000
        x14: 0000000000000315 x13: 0000000000000315 x12: 0000000000000000
        x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
        x8 : ffff80000805bc28 x7 : 0000000000000000 x6 : 0000000000000000
        x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
        x2 : ffff327c00128000 x1 : 0000000000000000 x0 : ffff327c039c59b0
        Call trace:
         drm_modeset_lock_all_ctx+0x3c4/0x3d0
         drm_atomic_helper_shutdown+0x70/0x134
         msm_drv_shutdown+0x30/0x40
         platform_shutdown+0x28/0x40
         device_shutdown+0x148/0x350
         kernel_power_off+0x38/0x80
         __do_sys_reboot+0x288/0x2c0
         __arm64_sys_reboot+0x28/0x34
         invoke_syscall+0x48/0x114
         el0_svc_common.constprop.0+0x44/0xec
         do_el0_svc+0x2c/0xc0
         el0_svc+0x2c/0x84
         el0t_64_sync_handler+0x11c/0x150
         el0t_64_sync+0x18c/0x190
        ---[ end trace 0000000000000000 ]---
        Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
        Mem abort info:
          ESR = 0x0000000096000004
          EC = 0x25: DABT (current EL), IL = 32 bits
          SET = 0, FnV = 0
          EA = 0, S1PTW = 0
          FSC = 0x04: level 0 translation fault
        Data abort info:
          ISV = 0, ISS = 0x00000004
          CM = 0, WnR = 0
        user pgtable: 4k pages, 48-bit VAs, pgdp=000000010eab1000
        [0000000000000018] pgd=0000000000000000, p4d=0000000000000000
        Internal error: Oops: 96000004 [#1] PREEMPT SMP
        ...
        Hardware name: Google CoachZ (rev3+) (DT)
        pstate: a0400009 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
        pc : ww_mutex_lock+0x28/0x32c
        lr : drm_modeset_lock_all_ctx+0x1b0/0x3d0
        sp : ffff80000805bb50
        x29: ffff80000805bb50 x28: ffff327c00128000 x27: 0000000000000000
        x26: 0000000000000000 x25: 0000000000000001 x24: 0000000000000018
        x23: ffff80000805bc10 x22: ffff327c039c5ad8 x21: ffff327c039c5800
        x20: ffff80000805bbe8 x19: 0000000000000018 x18: 0000000000000034
        x17: 000000040044ffff x16: ffffc95d80cac920 x15: 0000000000000000
        x14: 0000000000000315 x13: 0000000000000315 x12: 0000000000000000
        x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
        x8 : ffff80000805bc28 x7 : 0000000000000000 x6 : 0000000000000000
        x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
        x2 : ffff327c00128000 x1 : 0000000000000000 x0 : 0000000000000018
        Call trace:
         ww_mutex_lock+0x28/0x32c
         drm_modeset_lock_all_ctx+0x1b0/0x3d0
         drm_atomic_helper_shutdown+0x70/0x134
         msm_drv_shutdown+0x30/0x40
         platform_shutdown+0x28/0x40
         device_shutdown+0x148/0x350
         kernel_power_off+0x38/0x80
         __do_sys_reboot+0x288/0x2c0
         __arm64_sys_reboot+0x28/0x34
         invoke_syscall+0x48/0x114
         el0_svc_common.constprop.0+0x44/0xec
         do_el0_svc+0x2c/0xc0
         el0_svc+0x2c/0x84
         el0t_64_sync_handler+0x11c/0x150
         el0t_64_sync+0x18c/0x190
        Code: aa0103f4 d503201f d2800001 aa0103e3 (c8e37c02)
        ---[ end trace 0000000000000000 ]---
        Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
        Kernel Offset: 0x495d77c00000 from 0xffff800008000000
        PHYS_OFFSET: 0xffffcd8500000000
        CPU features: 0x800,00c2a015,19801c82
        Memory Limit: none
        ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---
      
      Fixes: 9d5cbf5f ("drm/msm: add shutdown support for display platform_driver")
      Signed-off-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
      Reviewed-by: default avatarAbhinav Kumar <quic_abhinavk@quicinc.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20220816134612.916527-1-javierm@redhat.com
      0a58d2ae
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