| Message ID | 20241014093605.2.I72441365ffe91f3dceb17db0a8ec976af8139590@changeid (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | [1/3] drm/msm: Avoid NULL dereference in msm_disp_state_print_regs() | expand |
On 10/14/2024 9:36 AM, Douglas Anderson wrote: > With the "drm/msm: add a display mmu fault handler" series [1] we saw > issues in the field where memory allocation was failing when > allocating space for registers in msm_disp_state_dump_regs(). > Specifically we were seeing an order 5 allocation fail. It's not > surprising that order 5 allocations will sometimes fail after the > system has been up and running for a while. > > There's no need here for contiguous memory. Change the allocation to > kvzalloc() which should make it much less likely to fail. > > [1] https://lore.kernel.org/r/20240628214848.4075651-1-quic_abhinavk@quicinc.com/ > > Fixes: 98659487b845 ("drm/msm: add support to take dpu snapshot") > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > I had some doubts on how this issue happens considering that the devcore should automatically release the memory within 5 sec even if userspace had not read this. So there is no leak as such, its just that in a heavily loaded system, this can happen. Fix looks okay to me, Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
diff --git a/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c b/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c index bb149281d31f..4d55e3cf570f 100644 --- a/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c +++ b/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c @@ -26,7 +26,7 @@ static void msm_disp_state_dump_regs(u32 **reg, u32 aligned_len, void __iomem *b end_addr = base_addr + aligned_len; if (!(*reg)) - *reg = kzalloc(len_padded, GFP_KERNEL); + *reg = kvzalloc(len_padded, GFP_KERNEL); if (*reg) dump_addr = *reg; @@ -162,7 +162,7 @@ void msm_disp_state_free(void *data) list_for_each_entry_safe(block, tmp, &disp_state->blocks, node) { list_del(&block->node); - kfree(block->state); + kvfree(block->state); kfree(block); }
With the "drm/msm: add a display mmu fault handler" series [1] we saw issues in the field where memory allocation was failing when allocating space for registers in msm_disp_state_dump_regs(). Specifically we were seeing an order 5 allocation fail. It's not surprising that order 5 allocations will sometimes fail after the system has been up and running for a while. There's no need here for contiguous memory. Change the allocation to kvzalloc() which should make it much less likely to fail. [1] https://lore.kernel.org/r/20240628214848.4075651-1-quic_abhinavk@quicinc.com/ Fixes: 98659487b845 ("drm/msm: add support to take dpu snapshot") Signed-off-by: Douglas Anderson <dianders@chromium.org> --- drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)