Buildresult: powerpc-next/powerpc-allnoconfig/powerpc-gcc4.6 built on Feb 28 2019, 14:59

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Status:	OK
Date/Time:	Feb 28 2019, 14:59
Duration:	0:00:19.106845
Builder:	ka2
Revision:	powerpc/powernv/ioda: Fix locked_vm counting for memory used by IOMMU tables (`11f5acce2fa43b015a8120fa7620fa4efd0a2952)`
Target:	powerpc-next/powerpc-allnoconfig/powerpc-gcc4.6
Branch:	powerpc-next
Compiler:	powerpc-gcc4.6 (powerpc-linux-gcc (GCC) 4.6.3 / GNU ld (GNU Binutils) 2.22)
Config:	allnoconfig (download)
Log:	Download original Possible warnings (1) kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] Full Log # git rev-parse -q --verify 11f5acce2fa43b015a8120fa7620fa4efd0a2952^{commit} 11f5acce2fa43b015a8120fa7620fa4efd0a2952 already have revision, skipping fetch # git checkout -q -f -B kisskb 11f5acce2fa43b015a8120fa7620fa4efd0a2952 # git clean -qxdf # < git log -1 # commit 11f5acce2fa43b015a8120fa7620fa4efd0a2952 # Author: Alexey Kardashevskiy <aik@ozlabs.ru> # Date: Wed Feb 13 14:38:18 2019 +1100 # # powerpc/powernv/ioda: Fix locked_vm counting for memory used by IOMMU tables # # We store 2 multilevel tables in iommu_table - one for the hardware and # one with the corresponding userspace addresses. Before allocating # the tables, the iommu_table_group_ops::get_table_size() hook returns # the combined size of the two and VFIO SPAPR TCE IOMMU driver adjusts # the locked_vm counter correctly. When the table is actually allocated, # the amount of allocated memory is stored in iommu_table::it_allocated_size # and used to decrement the locked_vm counter when we release the memory # used by the table; .get_table_size() and .create_table() calculate it # independently but the result is expected to be the same. # # However the allocator does not add the userspace table size to # .it_allocated_size so when we destroy the table because of VFIO PCI # unplug (i.e. VFIO container is gone but the userspace keeps running), # we decrement locked_vm by just a half of size of memory we are # releasing. # # To make things worse, since we enabled on-demand allocation of # indirect levels, it_allocated_size contains only the amount of memory # actually allocated at the table creation time which can just be a # fraction. It is not a problem with incrementing locked_vm (as # get_table_size() value is used) but it is with decrementing. # # As the result, we leak locked_vm and may not be able to allocate more # IOMMU tables after few iterations of hotplug/unplug. # # This sets it_allocated_size in the pnv_pci_ioda2_ops::create_table() # hook to what pnv_pci_ioda2_get_table_size() returns so from now on we # have a single place which calculates the maximum memory a table can # occupy. The original meaning of it_allocated_size is somewhat lost now # though. # # We do not ditch it_allocated_size whatsoever here and we do not call # get_table_size() from vfio_iommu_spapr_tce.c when decrementing # locked_vm as we may have multiple IOMMU groups per container and even # though they all are supposed to have the same get_table_size() # implementation, there is a small chance for failure or confusion. # # Fixes: 090bad39b237 ("powerpc/powernv: Add indirect levels to it_userspace") # Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> # Reviewed-by: David Gibson <david@gibson.dropbear.id.au> # Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-ld --version # < git log --format=%s --max-count=1 11f5acce2fa43b015a8120fa7620fa4efd0a2952 # < make -s -j 8 ARCH=powerpc O=/kisskb/build/powerpc-next_powerpc-allnoconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- allnoconfig # make -s -j 8 ARCH=powerpc O=/kisskb/build/powerpc-next_powerpc-allnoconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] Completed OK # rm -rf /kisskb/build/powerpc-next_powerpc-allnoconfig_powerpc-gcc4.6 # Build took: 0:00:19.106845

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