Re: [PATCH RESEND] iommu: dmar: Fix RCU list debugging warnings

[Lu Baolu]

On 2020/2/24 0:55, Amol Grover wrote:
> dmar_drhd_units is traversed using list_for_each_entry_rcu()
> outside of an RCU read side critical section but under the
> protection of dmar_global_lock. Hence add corresponding lockdep
> expression to silence the following false-positive warnings:
>
> [    1.603975] =============================
> [    1.603976] WARNING: suspicious RCU usage
> [    1.603977] 5.5.4-stable #17 Not tainted
> [    1.603978] -----------------------------
> [    1.603980] drivers/iommu/intel-iommu.c:4769 RCU-list traversed in non-reader section!!
>
> [    1.603869] =============================
> [    1.603870] WARNING: suspicious RCU usage
> [    1.603872] 5.5.4-stable #17 Not tainted
> [    1.603874] -----------------------------
> [    1.603875] drivers/iommu/dmar.c:293 RCU-list traversed in non-reader section!!
>
> Tested-by: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>
> Signed-off-by: Amol Grover <frextrite@xxxxxxxxx>

Thanks for the fix.

Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Best regards,
baolu