Re: [PATCH 1/3] bus: mhi: host: keep bhi buffer through suspend cycle

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jun 30, 2025 at 12:43:28PM +0500, Muhammad Usama Anjum wrote:
> When there is memory pressure, at resume time dma_alloc_coherent()
> returns error which in turn fails the loading of firmware and hence
> the driver crashes:
> 
> kernel: kworker/u33:5: page allocation failure: order:7,
> mode:0xc04(GFP_NOIO|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
> kernel: CPU: 1 UID: 0 PID: 7693 Comm: kworker/u33:5 Not tainted
> 6.11.11-valve17-1-neptune-611-g027868a0ac03 #1
> 3843143b92e9da0fa2d3d5f21f51beaed15c7d59

Please don't wrap kernel log lines.

> kernel: Hardware name: Valve Galileo/Galileo, BIOS F7G0112 08/01/2024
> kernel: Workqueue: mhi_hiprio_wq mhi_pm_st_worker [mhi]
> kernel: Call Trace:
> kernel:  <TASK>
> kernel:  dump_stack_lvl+0x4e/0x70
> kernel:  warn_alloc+0x164/0x190
> kernel:  ? srso_return_thunk+0x5/0x5f
> kernel:  ? __alloc_pages_direct_compact+0xaf/0x360
> kernel:  __alloc_pages_slowpath.constprop.0+0xc75/0xd70
> kernel:  __alloc_pages_noprof+0x321/0x350
> kernel:  __dma_direct_alloc_pages.isra.0+0x14a/0x290
> kernel:  dma_direct_alloc+0x70/0x270
> kernel:  mhi_fw_load_handler+0x126/0x340 [mhi
> a96cb91daba500cc77f86bad60c1f332dc3babdf]
> kernel:  mhi_pm_st_worker+0x5e8/0xac0 [mhi
> a96cb91daba500cc77f86bad60c1f332dc3babdf]

Same here.

> kernel:  ? srso_return_thunk+0x5/0x5f
> kernel:  process_one_work+0x17e/0x330
> kernel:  worker_thread+0x2ce/0x3f0
> kernel:  ? __pfx_worker_thread+0x10/0x10
> kernel:  kthread+0xd2/0x100
> kernel:  ? __pfx_kthread+0x10/0x10
> kernel:  ret_from_fork+0x34/0x50
> kernel:  ? __pfx_kthread+0x10/0x10
> kernel:  ret_from_fork_asm+0x1a/0x30
> kernel:  </TASK>
> kernel: Mem-Info:
> kernel: active_anon:513809 inactive_anon:152 isolated_anon:0
>     active_file:359315 inactive_file:2487001 isolated_file:0
>     unevictable:637 dirty:19 writeback:0
>     slab_reclaimable:160391 slab_unreclaimable:39729
>     mapped:175836 shmem:51039 pagetables:4415
>     sec_pagetables:0 bounce:0
>     kernel_misc_reclaimable:0
>     free:125666 free_pcp:0 free_cma:0
> 
> In above example, if we sum all the consumed memory, it comes out
> to be 15.5GB and free memory is ~ 500MB from a total of 16GB RAM.
> Even though memory is present. But all of the dma memory has been
> exhausted or fragmented.
> 
> Fix it by allocating it only once and then reuse the same allocated
> memory. As we'll allocate this memory only once, this memory will stay
> allocated.
> 
> Tested-on: WCN6855 WLAN.HSP.1.1-03926.13-QCAHSPSWPL_V2_SILICONZ_CE-2.52297.6
> 
> Fixes: cd457afb1667 ("bus: mhi: core: Add support for downloading firmware over BHIe")

No cc: stable?

> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
> ---
> Reported here:
> https://lore.kernel.org/all/ead32f5b-730a-4b81-b38f-93d822f990c6@collabora.com
> 
> Still a lot of more fixes are required. Hence, I'm not adding closes tag.
> ---
>  drivers/bus/mhi/host/boot.c     | 19 ++++++++++---------
>  drivers/bus/mhi/host/init.c     |  5 +++++
>  drivers/bus/mhi/host/internal.h |  2 ++
>  include/linux/mhi.h             |  1 +
>  4 files changed, 18 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c
> index b3a85aa3c4768..11bb8c12ac597 100644
> --- a/drivers/bus/mhi/host/boot.c
> +++ b/drivers/bus/mhi/host/boot.c
> @@ -302,8 +302,8 @@ static int mhi_fw_load_bhi(struct mhi_controller *mhi_cntrl,
>  	return -EIO;
>  }
>  
> -static void mhi_free_bhi_buffer(struct mhi_controller *mhi_cntrl,
> -				struct image_info *image_info)
> +void mhi_free_bhi_buffer(struct mhi_controller *mhi_cntrl,
> +			 struct image_info *image_info)
>  {
>  	struct mhi_buf *mhi_buf = image_info->mhi_buf;
>  
> @@ -455,18 +455,19 @@ static enum mhi_fw_load_type mhi_fw_load_type_get(const struct mhi_controller *m
>  
>  static int mhi_load_image_bhi(struct mhi_controller *mhi_cntrl, const u8 *fw_data, size_t size)
>  {
> -	struct image_info *image;
> +	struct image_info *image = mhi_cntrl->bhi_image;
>  	int ret;
>  
> -	ret = mhi_alloc_bhi_buffer(mhi_cntrl, &image, size);
> -	if (ret)
> -		return ret;
> +	if (!image) {

What prevents image from going away right after you tested it?

thanks,

greg k-h