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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI3MDA4NCBTYWx0ZWRfX8T43miitrpaA oRMW9g5RlS0oPRTfAAZVkBTfroEvMc7vL/efh+v6m4+Q7jlYtSC7vM4qohkOmwS2yZHWkfVaJES kBVc4daURrZkY2lb4pUzFkSuZoYi6roXs8V7ZJgcYYwr74v0TY1UMuMV+3WkVrbwQyV2VFYT1QV B923iA00Dv2/C8FlxpiEh+ve+xcytaNFdR6TYunBP8duyg2IVO5ASo0UwpxBcb6elhEtyPkda4h sXi03BaY7K1NrxCFrlGQWvNQSVl3hlRZIp+Na7J7XUephBkoUDrrCeVaYezZFWtPvTdHNJuz58x 3EKm6KnQRXgYltZ1NKTPvkR0M+HqqPxS/W5FkkuFrYBitdsuhmSD1AimlJGgoFDFetQj7KCB3JO 0chCMJK4+OHtnyTNoRQTRyWUCLA+gX9eHGWNgcnbpnH+YePs7Ckx/rEWb0kzOuvlUMpX9kK7x+j NDo+/kCE3AFE/HMwXYA== X-Proofpoint-Spam-Info: AW1haW4tMjYwODI3MDA4NCBTYWx0ZWRfX+22xjORpkXPN 7rWhwlNbqy4prgM1qO0FuCGQmGvV7jKOd6YKCQNqlbm5NPMgsVm4q3Fd3/ihgFGzltBqsmxTq0v 1Wa3Luly5NCLIFzE8Gw18tsRMkYRADI= X-Proofpoint-ORIG-GUID: xXPL5fcZcB2a1Kh2p44soRtdxbs4o4Ol X-Authority-Analysis: v=2.4 cv=RcqgzVtv c=1 sm=1 tr=0 ts=6a900de0 cx=c_pps a=vVfyC5vLCtgYJKYeQD43oA==:117 a=fChuTYTh2wq5r3m49p7fHw==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=YMgV9FUhrdKAYTUUvYB2:22 a=VwQbUJbxAAAA:8 a=EUspDBNiAAAA:8 a=1XWaLZrsAAAA:8 a=7CQSdrXTAAAA:8 a=C8WugiQ-6VtP81x-AMAA:9 a=QEXdDO2ut3YA:10 a=rl5im9kqc5Lf4LNbBjHf:22 a=a-qgeE7W1pNrGK8U0ZQC:22 X-Proofpoint-GUID: xXPL5fcZcB2a1Kh2p44soRtdxbs4o4Ol X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-27_04,2026-08-26_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 priorityscore=1501 adultscore=0 spamscore=0 bulkscore=0 phishscore=0 impostorscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608270084 On 4/25/2025 7:09 PM, Robin Murphy wrote: > Since it's not currently safe to take device_lock() in the IOMMU probe > path, that can race against really_probe() setting dev->driver before > attempting to bind. The race itself isn't so bad, since we're only > concerned with dereferencing dev->driver itself anyway, but sadly my > attempt to implement the check with minimal churn leads to a kind of > TOCTOU issue, where dev->driver becomes valid after to_amba_driver(NULL) > is already computed, and thus the check fails to work as intended. > > Will and I both hit this with the platform bus, but the pattern here is > the same, so fix it for correctness too. > > Reported-by: Will McVicker > Fixes: bcb81ac6ae3c ("iommu: Get DT/ACPI parsing into the proper probe path") > Signed-off-by: Robin Murphy arch_teardown_dma_ops(dev); Hello Robin We faced this issue with amba_dma_configure race internally as well: Call trace: amba_dma_configure __iommu_probe_device probe_iommu_group bus_for_each_dev iommu_device_register arm_smmu_device_probe platform_probe really_probe __driver_probe_device driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_scheduled_works worker_thread kthread ret_from_fork We raised change for this based on already merged changes that fixed the same TOCTOU race for the platform bus in commit 95deee37a123 ("platform: Fix race condition during DMA configure at IOMMU probe time") and for fsl-mc in commit 152f33ee30ee ("bus: fsl_mc: Fix driver_managed_dma check"). Link: https://lore.kernel.org/all/20260825-iommu_races-v2-1-49de6de71357@oss.qualcomm.com/ We later found this change you raised which was never merged. Can you please help to revive and take this change forward for merge. Reviewed-by: Ketan Kishore Regards Ketan