kernel/linux.git/drivers/accel/ethosu, branch linux-7.1.y

accel/ethosu: fix OOB write in ethosu_gem_cmdstream_copy_and_validate()

2026-06-05T03:07:59+00:00

The command stream parsing loop increments the index variable a second time when a 64-bit command word is encountered (bit 14 set), but does not re-check the loop bound before writing the second word: for (i = 0; i < size / 4; i++) { bocmds[i] = cmds[0]; if (cmd & 0x4000) { i++; bocmds[i] = cmds[1]; /* unchecked */ } } The buffer bocmds is backed by a DMA allocation of exactly size bytes from drm_gem_dma_create(ddev, size), giving valid indices [0, size/4-1]. When i == size/4 - 1 on entry to an iteration and bit 14 of cmds[0] is set, bocmds[size/4-1] is written in bounds, i is then incremented to size/4, and bocmds[size/4] writes four bytes past the end of the allocation. Userspace controls both the buffer contents and the size argument via the ioctl, making this a userspace-triggerable heap out-of-bounds write. Fix by checking the incremented index against the buffer bound before the second write and returning -EINVAL if the buffer is too small to contain the extended command. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260523190843.33977-1-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm)

accel/ethosu: reject DMA commands with uninitialized length

2026-06-04T22:43:43+00:00

cmd_state_init() initializes the command state with memset(0xff), leaving dma->len at U64_MAX to signal missing setup. The only setter is NPU_SET_DMA0_LEN; if userspace omits this command and issues NPU_OP_DMA_START, dma->len remains U64_MAX. In dma_length(), a positive stride added to U64_MAX wraps to a small value. With size0 == 1, check_mul_overflow() does not trigger and dma_length() returns 0 instead of U64_MAX. The caller's U64_MAX check then passes, region_size[] stays 0, and the bounds check in ethosu_job.c is bypassed, allowing hardware to execute DMA with stale physical addresses. Fix by checking for U64_MAX at the start of dma_length() before any arithmetic, consistent with the sentinel value used throughout the driver to detect uninitialized fields. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260524130319.12747-1-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm)

accel/ethosu: fix arithmetic issues in dma_length()

2026-06-04T22:43:27+00:00

dma_length() derives DMA region usage from command stream values and updates region_size[]: len = ((len + stride[0]) * size0 + stride[1]) * size1 region_size[region] = max(..., len + dma->offset) Several arithmetic issues can corrupt the derived region size: - signed stride values may underflow when added to len - intermediate multiplications may overflow - len + dma->offset may overflow during region_size updates - dma_length() error returns were not validated by the caller region_size[] is later used by ethosu_job.c to validate command stream accesses against GEM buffer sizes. Arithmetic wraparound can therefore under-report region usage and bypass the bounds validation. Fix by validating signed additions, using overflow helpers for multiplications and offset updates, and propagating dma_length() failures to the caller. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260524103710.47397-1-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm)

accel/ethosu: fix wrong weight index in NPU_SET_SCALE1_LENGTH on U85

2026-06-04T22:41:46+00:00

On non-U65 hardware (e.g. U85), opcode 0x4093 is NPU_SET_WEIGHT2_LENGTH. The BASE handler for the same opcode correctly assigns to st.weight[2].base, but the LENGTH handler mistakenly assigns cmds[1] to st.weight[1].length instead of st.weight[2].length. This leaves weight[2].length at its initialised sentinel value of 0xffffffff and corrupts weight[1].length with the user-supplied value, breaking the software bounds-check state for both weight buffers on U85. Fix the index to match the BASE handler. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260523210840.92039-3-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm)

accel/ethosu: reject NPU_OP_RESIZE commands from userspace

2026-06-04T22:41:46+00:00

NPU_OP_RESIZE is a U85-only command that the driver does not yet implement. The existing WARN_ON(1) placeholder fires unconditionally whenever userspace submits this command via DRM_IOCTL_ETHOSU_GEM_CREATE, causing unbounded kernel log spam. If panic_on_warn is set the kernel panics, giving any unprivileged user with access to the DRM device a trivial denial-of-service primitive. Replace the WARN_ON(1) with an explicit -EINVAL return so the ioctl rejects the command before it reaches hardware. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260523210840.92039-2-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm)

accel/ethosu: fix IFM region index out-of-bounds in command stream parser

2026-06-04T22:31:41+00:00

NPU_SET_IFM_REGION extracts the region index with param & 0x7f, giving a maximum value of 127. However region_size[] and output_region[] in struct ethosu_validated_cmdstream_info are both sized to NPU_BASEP_REGION_MAX (8), giving valid indices [0..7]. Every other region assignment in the same switch uses param & 0x7: NPU_SET_OFM_REGION: st.ofm.region = param & 0x7; NPU_SET_IFM2_REGION: st.ifm2.region = param & 0x7; NPU_SET_WEIGHT_REGION: st.weight[0].region = param & 0x7; NPU_SET_SCALE_REGION: st.scale[0].region = param & 0x7; The 0x7f mask on IFM is inconsistent and appears to be a typo. feat_matrix_length() and calc_sizes() use the region index directly as an array subscript into the kzalloc'd info struct: info->region_size[fm->region] = max(...); A userspace caller supplying NPU_SET_IFM_REGION with param > 7 causes a write up to 127*8 = 1016 bytes past the start of region_size[], corrupting adjacent kernel heap data. Fix by applying the same & 0x7 mask used by all other region assignments. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260523195159.55801-1-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm)

accel: ethosu: Add hardware dependency hint

2026-04-02T20:18:14+00:00

The Ethos-U NPU is only available on ARM systems, so add a hardware dependency hint to prevent this driver from being needlessly included in kernels built for other architectures. Signed-off-by: Jean Delvare Link: https://patch.msgid.link/20260401122323.6127a77c@endymion Signed-off-by: Rob Herring (Arm)

accel: ethosu: Handle possible underflow in IFM size calculations

2026-03-05T21:21:17+00:00

If the command stream has larger padding sizes than the IFM and OFM diminsions, then the calculations will underflow to a negative value. The result is a very large region bounds which is caught on submit, but it's better to catch it earlier. Current mesa ethosu driver has a signedness bug which resulted in padding of 127 (the max) and triggers this issue. Reviewed-and-Tested-by: Anders Roxell Link: https://patch.msgid.link/20260218-ethos-fixes-v1-3-be3fa3ea9a30@kernel.org Signed-off-by: Rob Herring (Arm)

accel: ethosu: Fix NPU_OP_ELEMENTWISE validation with scalar

2026-03-05T21:21:17+00:00

The NPU_OP_ELEMENTWISE instruction uses a scalar value for IFM2 if the IFM2_BROADCAST "scalar" mode is set. It is a bit (7) on the u65 and part of a field (bits 3:0) on the u85. The driver was hardcoded to the u85. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Reviewed-and-Tested-by: Anders Roxell Link: https://patch.msgid.link/20260218-ethos-fixes-v1-2-be3fa3ea9a30@kernel.org Signed-off-by: Rob Herring (Arm)

accel: ethosu: Fix job submit error clean-up refcount underflows

2026-03-05T21:21:17+00:00

If the job submit fails before adding the job to the scheduler queue such as when the GEM buffer bounds checks fail, then doing a ethosu_job_put() results in a pm_runtime_put_autosuspend() without the corresponding pm_runtime_resume_and_get(). The dma_fence_put()'s are also unnecessary, but seem to be harmless. Split the ethosu_job_cleanup() function into 2 parts for the before and after the job is queued. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Reviewed-and-Tested-by: Anders Roxell Link: https://patch.msgid.link/20260218-ethos-fixes-v1-1-be3fa3ea9a30@kernel.org Signed-off-by: Rob Herring (Arm)