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From: Joerg Roedel <jroedel@suse.de>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/vt-d: silence a RCU-list debugging warning
Date: Thu, 19 Mar 2020 15:16:19 +0100	[thread overview]
Message-ID: <20200319141619.GC611@suse.de> (raw)
In-Reply-To: <36b9e69b-ee3f-c17d-1788-64448ce8bc14@linux.intel.com>

On Wed, Mar 18, 2020 at 01:27:53PM +0800, Lu Baolu wrote:
> On 2020/3/17 23:03, Qian Cai wrote:
> > dmar_find_atsr() calls list_for_each_entry_rcu() outside of an RCU read
> > side critical section but with dmar_global_lock held. Silence this
> > false positive.
> > 
> >   drivers/iommu/intel-iommu.c:4504 RCU-list traversed in non-reader section!!
> >   1 lock held by swapper/0/1:
> >   #0: ffffffff9755bee8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1a6/0xe19
> > 
> >   Call Trace:
> >    dump_stack+0xa4/0xfe
> >    lockdep_rcu_suspicious+0xeb/0xf5
> >    dmar_find_atsr+0x1ab/0x1c0
> >    dmar_parse_one_atsr+0x64/0x220
> >    dmar_walk_remapping_entries+0x130/0x380
> >    dmar_table_init+0x166/0x243
> >    intel_iommu_init+0x1ab/0xe19
> >    pci_iommu_init+0x1a/0x44
> >    do_one_initcall+0xae/0x4d0
> >    kernel_init_freeable+0x412/0x4c5
> >    kernel_init+0x19/0x193
> > 
> > Signed-off-by: Qian Cai <cai@lca.pw>
> 
> How about changing the commit subject to
> "iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr()"?
> 
> Acked-by: Lu Baolu <baolu.lu@linux.intel.com>

Fixed up the subject and applied it, thanks.
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WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <jroedel@suse.de>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Qian Cai <cai@lca.pw>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/vt-d: silence a RCU-list debugging warning
Date: Thu, 19 Mar 2020 15:16:19 +0100	[thread overview]
Message-ID: <20200319141619.GC611@suse.de> (raw)
In-Reply-To: <36b9e69b-ee3f-c17d-1788-64448ce8bc14@linux.intel.com>

On Wed, Mar 18, 2020 at 01:27:53PM +0800, Lu Baolu wrote:
> On 2020/3/17 23:03, Qian Cai wrote:
> > dmar_find_atsr() calls list_for_each_entry_rcu() outside of an RCU read
> > side critical section but with dmar_global_lock held. Silence this
> > false positive.
> > 
> >   drivers/iommu/intel-iommu.c:4504 RCU-list traversed in non-reader section!!
> >   1 lock held by swapper/0/1:
> >   #0: ffffffff9755bee8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1a6/0xe19
> > 
> >   Call Trace:
> >    dump_stack+0xa4/0xfe
> >    lockdep_rcu_suspicious+0xeb/0xf5
> >    dmar_find_atsr+0x1ab/0x1c0
> >    dmar_parse_one_atsr+0x64/0x220
> >    dmar_walk_remapping_entries+0x130/0x380
> >    dmar_table_init+0x166/0x243
> >    intel_iommu_init+0x1ab/0xe19
> >    pci_iommu_init+0x1a/0x44
> >    do_one_initcall+0xae/0x4d0
> >    kernel_init_freeable+0x412/0x4c5
> >    kernel_init+0x19/0x193
> > 
> > Signed-off-by: Qian Cai <cai@lca.pw>
> 
> How about changing the commit subject to
> "iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr()"?
> 
> Acked-by: Lu Baolu <baolu.lu@linux.intel.com>

Fixed up the subject and applied it, thanks.

  parent reply	other threads:[~2020-03-19 14:16 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-17 15:03 [PATCH] iommu/vt-d: silence a RCU-list debugging warning Qian Cai
2020-03-17 15:03 ` Qian Cai
2020-03-18  5:27 ` Lu Baolu
2020-03-18  5:27   ` Lu Baolu
2020-03-18 11:14   ` Qian Cai
2020-03-18 11:14     ` Qian Cai
2020-03-19 14:16   ` Joerg Roedel [this message]
2020-03-19 14:16     ` Joerg Roedel

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