Calling dma_unmap_sg() in drm_gem_shmem_free_object() is too late if the backing pages have already been released by the shrinker. The result is the following abort:
Unable to handle kernel paging request at virtual address ffff8000098ed000 Mem abort info: ESR = 0x96000147 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000147 CM = 1, WnR = 1 swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000002f51000 [ffff8000098ed000] pgd=00000000401f8003, pud=00000000401f7003, pmd=00000000401b1003, pte=00e80000098ed712 Internal error: Oops: 96000147 [#1] SMP Modules linked in: panfrost gpu_sched CPU: 5 PID: 902 Comm: gnome-shell Not tainted 5.3.0-rc1+ #95 Hardware name: 96boards Rock960 (DT) pstate: 40000005 (nZcv daif -PAN -UAO) pc : __dma_inv_area+0x40/0x58 lr : arch_sync_dma_for_cpu+0x28/0x30 sp : ffff00001321ba30 x29: ffff00001321ba30 x28: ffff00001321bd08 x27: 0000000000000000 x26: 0000000000000009 x25: 0000ffffc1f86170 x24: 0000000000000000 x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000021000 x20: ffff80003bb2d810 x19: 00000000098ed000 x18: 0000000000000000 x17: 0000000000000000 x16: ffff800023fd9480 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 00000000fffb9fff x10: 0000000000000000 x9 : 0000000000000000 x8 : ffff800023fd9c18 x7 : 0000000000000000 x6 : 00000000ffffffff x5 : 0000000000000000 x4 : 0000000000021000 Purging 5693440 bytes x3 : 000000000000003f x2 : 0000000000000040 x1 : ffff80000990e000 x0 : ffff8000098ed000 Call trace: __dma_inv_area+0x40/0x58 dma_direct_sync_single_for_cpu+0x7c/0x80 dma_direct_unmap_page+0x80/0x88 dma_direct_unmap_sg+0x54/0x80 drm_gem_shmem_free_object+0xfc/0x108 panfrost_gem_free_object+0x118/0x128 [panfrost] drm_gem_object_free+0x18/0x90 drm_gem_object_put_unlocked+0x58/0x80 drm_gem_object_handle_put_unlocked+0x64/0xb0 drm_gem_object_release_handle+0x70/0x98 drm_gem_handle_delete+0x64/0xb0 drm_gem_close_ioctl+0x28/0x38 drm_ioctl_kernel+0xb8/0x110 drm_ioctl+0x244/0x3f0 do_vfs_ioctl+0xbc/0x910 ksys_ioctl+0x78/0xa8 __arm64_sys_ioctl+0x1c/0x28 el0_svc_common.constprop.0+0x88/0x150 el0_svc_handler+0x28/0x78 el0_svc+0x8/0xc Code: 8a230000 54000060 d50b7e20 14000002 (d5087620)
Fixes: 17acb9f35ed7 ("drm/shmem: Add madvise state and purge helpers") Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard maxime.ripard@bootlin.com Cc: Sean Paul sean@poorly.run Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Reviewed-by: Steven Price steven.price@arm.com Signed-off-by: Rob Herring robh@kernel.org --- drivers/gpu/drm/drm_gem_shmem_helper.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index df8f2c8adb2b..5423ec56b535 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -390,6 +390,12 @@ void drm_gem_shmem_purge_locked(struct drm_gem_object *obj)
WARN_ON(!drm_gem_shmem_is_purgeable(shmem));
+ dma_unmap_sg(obj->dev->dev, shmem->sgt->sgl, + shmem->sgt->nents, DMA_BIDIRECTIONAL); + sg_free_table(shmem->sgt); + kfree(shmem->sgt); + shmem->sgt = NULL; + drm_gem_shmem_put_pages_locked(shmem);
shmem->madv = -1;