Re: [PATCH] fix: accel/habanalabs: hl_cs_signal_sob_wraparound_handler: missing hw_sob_get when need_reset is true and encaps_sig is false

[WenTao Liang]

> 2026年6月26日 18:44，WenTao Liang <vulab@xxxxxxxxxxx> 写道：
> 
> When other_sob->need_reset is true and encaps_sig is false,
>  hw_sob_put(other_sob) decrements the kref to 0, but the matching
>  hw_sob_get(other_sob) is skipped because it is inside the encaps_sig
>  block. The function returns other_sob with kref=0, causing a subsequent
>  kref_put to underflow. Fix by adding hw_sob_get(other_sob) in the else
>  branch.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: dadf17abb724 ("habanalabs: add support for encapsulated signals reservation")
> Signed-off-by: WenTao Liang <vulab@xxxxxxxxxxx>
> ---
> drivers/accel/habanalabs/common/command_submission.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/accel/habanalabs/common/command_submission.c b/drivers/accel/habanalabs/common/command_submission.c
> index ba4257bda77b..675301dfc0ef 100644
> --- a/drivers/accel/habanalabs/common/command_submission.c
> +++ b/drivers/accel/habanalabs/common/command_submission.c
> @@ -1860,11 +1860,10 @@ int hl_cs_signal_sob_wraparound_handler(struct hl_device *hdev, u32 q_idx,
> 		if (other_sob->need_reset)
> 			hw_sob_put(other_sob);
> 
> -		if (encaps_sig) {
> +		if (encaps_sig)
> 			/* set reset indication for the sob */
> 			sob->need_reset = true;
> -			hw_sob_get(other_sob);
> -		}
> +		hw_sob_get(other_sob);
> 
> 		dev_dbg(hdev->dev, "switched to SOB %d, q_idx: %d\n",
> 				prop->curr_sob_offset, q_idx);
> -- 
> 2.39.5 (Apple Git-154)

Please ignore this patch. I will resend a proper version after
learning the kernel submission process.

Apologies for the noise.

Best regards,
WenTao Liang