From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
Tyrel Datwyler <tyreld@linux.ibm.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH AUTOSEL 4.14 038/186] powerpc/pseries/vio: Fix iommu_table use-after-free refcount warning
Date: Fri, 14 Feb 2020 11:14:47 -0500 [thread overview]
Message-ID: <20200214161715.18113-38-sashal@kernel.org> (raw)
In-Reply-To: <20200214161715.18113-1-sashal@kernel.org>
From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
[ Upstream commit aff8c8242bc638ba57247ae1ec5f272ac3ed3b92 ]
Commit e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to
iommu_table") missed an iommu_table allocation in the pseries vio code.
The iommu_table is allocated with kzalloc and as a result the associated
kref gets a value of zero. This has the side effect that during a DLPAR
remove of the associated virtual IOA the iommu_tce_table_put() triggers
a use-after-free underflow warning.
Call Trace:
[c0000002879e39f0] [c00000000071ecb4] refcount_warn_saturate+0x184/0x190
(unreliable)
[c0000002879e3a50] [c0000000000500ac] iommu_tce_table_put+0x9c/0xb0
[c0000002879e3a70] [c0000000000f54e4] vio_dev_release+0x34/0x70
[c0000002879e3aa0] [c00000000087cfa4] device_release+0x54/0xf0
[c0000002879e3b10] [c000000000d64c84] kobject_cleanup+0xa4/0x240
[c0000002879e3b90] [c00000000087d358] put_device+0x28/0x40
[c0000002879e3bb0] [c0000000007a328c] dlpar_remove_slot+0x15c/0x250
[c0000002879e3c50] [c0000000007a348c] remove_slot_store+0xac/0xf0
[c0000002879e3cd0] [c000000000d64220] kobj_attr_store+0x30/0x60
[c0000002879e3cf0] [c0000000004ff13c] sysfs_kf_write+0x6c/0xa0
[c0000002879e3d10] [c0000000004fde4c] kernfs_fop_write+0x18c/0x260
[c0000002879e3d60] [c000000000410f3c] __vfs_write+0x3c/0x70
[c0000002879e3d80] [c000000000415408] vfs_write+0xc8/0x250
[c0000002879e3dd0] [c0000000004157dc] ksys_write+0x7c/0x120
[c0000002879e3e20] [c00000000000b278] system_call+0x5c/0x68
Further, since the refcount was always zero the iommu_tce_table_put()
fails to call the iommu_table release function resulting in a leak.
Fix this issue be initilizing the iommu_table kref immediately after
allocation.
Fixes: e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to iommu_table")
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1579558202-26052-1-git-send-email-tyreld@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/pseries/vio.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index d86938260a867..fc778865a4124 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1195,6 +1195,8 @@ static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
if (tbl == NULL)
return NULL;
+ kref_init(&tbl->it_kref);
+
of_parse_dma_window(dev->dev.of_node, dma_window,
&tbl->it_index, &offset, &size);
--
2.20.1
next prev parent reply other threads:[~2020-02-14 19:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200214161715.18113-1-sashal@kernel.org>
2020-02-14 16:14 ` [PATCH AUTOSEL 4.14 004/186] soc: fsl: qe: change return type of cpm_muram_alloc() to s32 Sasha Levin
2020-02-14 16:14 ` [PATCH AUTOSEL 4.14 017/186] powerpc/powernv/iov: Ensure the pdn for VFs always contains a valid PE number Sasha Levin
2020-02-14 16:14 ` Sasha Levin [this message]
2020-02-14 16:15 ` [PATCH AUTOSEL 4.14 063/186] net/wan/fsl_ucc_hdlc: reject muram offsets above 64K Sasha Levin
2020-02-14 16:15 ` [PATCH AUTOSEL 4.14 091/186] net/wan/fsl_ucc_hdlc: remove set but not used variables 'ut_info' and 'ret' Sasha Levin
2020-02-14 16:15 ` [PATCH AUTOSEL 4.14 104/186] soc: fsl: qe: remove set but not used variable 'mm_gc' Sasha Levin
2020-02-14 16:16 ` [PATCH AUTOSEL 4.14 140/186] ide: remove set but not used variable 'hwif' Sasha Levin
2020-02-14 16:16 ` [PATCH AUTOSEL 4.14 155/186] powerpc/sriov: Remove VF eeh_dev state when disabling SR-IOV Sasha Levin
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