v5.15-rc7 AMD no kernel dump, spews "scsi_dma_map failed: request for 36 bytes!"
From: Marshall Midden
Date: Wed Oct 27 2021 - 12:09:07 EST
v5.15-rc7 AMD no kernel dump, spews "scsi_dma_map failed: request for 36 bytes!"
With v5.15-rc (1 through 7), AMD processor kernel crash dumps do not occur,
instead spews:
"scsci_dma_map failed: request for 36 bytes!"
Works on Intel machines, and in v5.14.0 (and v5.14.14) - as well as previous
kernels (down to v5.3.x.)
git bisect torvalds repository shows: dabb16f67215918c48cf3ff1fc4bc36ca421da2b
Reverse patch to tag v5.15-rc7 allows kernel crash dumps to occur/happen.
Extra details in github repository:
https://github.com/marshallmidden/m4.git
Directory AMD-cdrash-2021-10-27
Z.config.2021-10-27_10-27-15
Z.dabb16f67215918c48cf3ff1fc4bc36ca421da2b
Z.df-fstab
Z.dmesg.2021-10-27_10-26-34
Z.lspci-vmmD.2021-10-27_10-29-58
rpviewer(5).png
Reproduce via:
echo c > /proc/sysrq-trigger
git bisect of linux from torvalds repository shows:
commit dabb16f67215918c48cf3ff1fc4bc36ca421da2b
Author: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Date: Thu Jul 29 14:15:22 2021 -0600
iommu/dma: return error code from iommu_dma_map_sg()
Return appropriate error codes EINVAL or ENOMEM from
iommup_dma_map_sg(). If lower level code returns ENOMEM, then we
return it, other errors are coalesced into EINVAL.
iommu_dma_map_sg_swiotlb() returns -EIO as its an unknown error
from a call that returns DMA_MAPPING_ERROR.
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
------------------------------------------------------------------------------
[root@parsec torvalds-linux]# awk -f scripts/ver_linux
Linux parsec 5.15.0-rc4+ #22 SMP Tue Oct 26 18:50:50 CDT 2021
x86_64 x86_64 x86_64 GNU/Linux
GNU C 11.1.0
GNU Make 3.82
Binutils 2.36.1
Util-linux 2.23.2
Mount 2.23.2
Module-init-tools 20
E2fsprogs 1.42.9
Xfsprogs 4.5.0
Quota-tools 4.01
Nfs-utils 1.3.0
Bison 3.0.4
Flex 2.5.37
Linux C++ Library 6.0.19
Linux C Library 2.17
Dynamic linker (ldd) 2.17
Procps 3.3.10
Net-tools 2.10
Kbd 1.15.5
Console-tools 1.15.5
Sh-utils 8.22
Udev 219
Modules Loaded iscsi_target_mod qla2xxx
target_core_file target_core_iblock target_core_mod target_core_pscsi
tcm_fc tcm_loop tcm_qla2xxx
[root@parsec torvalds-linux]# perl scripts/get_maintainer.pl -f
drivers/iommu/dma-iommu.c
Joerg Roedel <joro@xxxxxxxxxx> (maintainer:IOMMU DRIVERS)
Will Deacon <will@xxxxxxxxxx> (maintainer:IOMMU DRIVERS)
iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx (open list:IOMMU DRIVERS)
linux-kernel@xxxxxxxxxxxxxxx (open list)
------------------------------------------------------------------------------
commit dabb16f67215918c48cf3ff1fc4bc36ca421da2b
Author: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Date: Thu Jul 29 14:15:22 2021 -0600
iommu/dma: return error code from iommu_dma_map_sg()
Return appropriate error codes EINVAL or ENOMEM from
iommup_dma_map_sg(). If lower level code returns ENOMEM, then we
return it, other errors are coalesced into EINVAL.
iommu_dma_map_sg_swiotlb() returns -EIO as its an unknown error
from a call that returns DMA_MAPPING_ERROR.
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 98ba927..168434c 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -972,7 +972,7 @@ static int iommu_dma_map_sg_swiotlb(struct device
*dev, struct scatterlist *sg,
out_unmap:
iommu_dma_unmap_sg_swiotlb(dev, sg, i, dir, attrs |
DMA_ATTR_SKIP_CPU_SYNC);
- return 0;
+ return -EIO;
}
/*
@@ -993,11 +993,13 @@ static int iommu_dma_map_sg(struct device *dev,
struct scatterlist *sg,
dma_addr_t iova;
size_t iova_len = 0;
unsigned long mask = dma_get_seg_boundary(dev);
+ ssize_t ret;
int i;
- if (static_branch_unlikely(&iommu_deferred_attach_enabled) &&
- iommu_deferred_attach(dev, domain))
- return 0;
+ if (static_branch_unlikely(&iommu_deferred_attach_enabled)) {
+ ret = iommu_deferred_attach(dev, domain);
+ goto out;
+ }
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
@@ -1045,14 +1047,17 @@ static int iommu_dma_map_sg(struct device
*dev, struct scatterlist *sg,
}
iova = iommu_dma_alloc_iova(domain, iova_len, dma_get_mask(dev), dev);
- if (!iova)
+ if (!iova) {
+ ret = -ENOMEM;
goto out_restore_sg;
+ }
/*
* We'll leave any physical concatenation to the IOMMU driver's
* implementation - it knows better than we do.
*/
- if (iommu_map_sg_atomic(domain, iova, sg, nents, prot) < iova_len)
+ ret = iommu_map_sg_atomic(domain, iova, sg, nents, prot);
+ if (ret < iova_len)
goto out_free_iova;
return __finalise_sg(dev, sg, nents, iova);
@@ -1061,7 +1066,10 @@ static int iommu_dma_map_sg(struct device *dev,
struct scatterlist *sg,
iommu_dma_free_iova(cookie, iova, iova_len, NULL);
out_restore_sg:
__invalidate_sg(sg, nents);
- return 0;
+out:
+ if (ret != -ENOMEM)
+ return -EINVAL;
+ return ret;
}
static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,