[Linux-kernel-mentees] [PATCH RESEND] iommu: dmar: Fix RCU list debugging warnings

Joerg Roedel joro at 8bytes.org
Mon Mar 2 16:04:13 UTC 2020


On Sun, Feb 23, 2020 at 10:25:39PM +0530, 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 at gmail.com>
> Signed-off-by: Amol Grover <frextrite at gmail.com>
> ---
>  include/linux/dmar.h | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

Applied, thanks.


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