On 23/09/2025 15:04, Rob Clark wrote:
Imported dma-bufs also have obj->resv != &obj->_resv. So we should check both this condition in addition to flags for handling the _NO_SHARE case.Fixes this splat that was reported with IRIS video playback: ------------[ cut here ]------------ WARNING: CPU: 3 PID: 2040 at drivers/gpu/drm/msm/msm_gem.c:1127 msm_gem_free_object+0x1f8/0x264 [msm] CPU: 3 UID: 1000 PID: 2040 Comm: .gnome-shell-wr Not tainted 6.17.0-rc7 #1 PREEMPT pstate: 81400005 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : msm_gem_free_object+0x1f8/0x264 [msm] lr : msm_gem_free_object+0x138/0x264 [msm] sp : ffff800092a1bb30 x29: ffff800092a1bb80 x28: ffff800092a1bce8 x27: ffffbc702dbdbe08 x26: 0000000000000008 x25: 0000000000000009 x24: 00000000000000a6 x23: ffff00083c72f850 x22: ffff00083c72f868 x21: ffff00087e69f200 x20: ffff00087e69f330 x19: ffff00084d157ae0 x18: 0000000000000000 x17: 0000000000000000 x16: ffffbc704bd46b80 x15: 0000ffffd0959540 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: ffffbc702e6cdb48 x10: 0000000000000000 x9 : 000000000000003f x8 : ffff800092a1ba90 x7 : 0000000000000000 x6 : 0000000000000020 x5 : ffffbc704bd46c40 x4 : fffffdffe102cf60 x3 : 0000000000400032 x2 : 0000000000020000 x1 : ffff00087e6978e8 x0 : ffff00087e6977e8 Call trace: msm_gem_free_object+0x1f8/0x264 [msm] (P) drm_gem_object_free+0x1c/0x30 [drm] drm_gem_object_handle_put_unlocked+0x138/0x150 [drm] drm_gem_object_release_handle+0x5c/0xcc [drm] drm_gem_handle_delete+0x68/0xbc [drm] drm_gem_close_ioctl+0x34/0x40 [drm] drm_ioctl_kernel+0xc0/0x130 [drm] drm_ioctl+0x360/0x4e0 [drm] __arm64_sys_ioctl+0xac/0x104 invoke_syscall+0x48/0x104 el0_svc_common.constprop.0+0x40/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x34/0xec el0t_64_sync_handler+0xa0/0xe4 el0t_64_sync+0x198/0x19c ---[ end trace 0000000000000000 ]--- ------------[ cut here ]------------ Reported-by: Stephan Gerhold <[email protected]> Fixes: de651b6e040b ("drm/msm: Fix refcnt underflow in error path") Signed-off-by: Rob Clark <[email protected]> --- drivers/gpu/drm/msm/msm_gem.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index 9f0f5b77f1bd..3aea9b493375 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -1121,12 +1121,16 @@ static void msm_gem_free_object(struct drm_gem_object *obj) put_pages(obj); } - if (obj->resv != &obj->_resv) { + /* + * In error paths, we could end up here before msm_gem_new_handle() + * has changed obj->resv to point to the shared resv. In this case, + * we don't want to drop a ref to the shared r_obj that we haven't + * taken yet. + */ + if ((msm_obj->flags & MSM_BO_NO_SHARE) && (obj->resv != &obj->_resv)) { struct drm_gem_object *r_obj = container_of(obj->resv, struct drm_gem_object, _resv); - WARN_ON(!(msm_obj->flags & MSM_BO_NO_SHARE)); - /* Drop reference we hold to shared resv obj: */ drm_gem_object_put(r_obj); } -- 2.51.0
Tested-by: Bryan O'Donoghue <[email protected]> # qrb5165-rb5
