Commit 8f1fc1bf1a3d ("dma: contiguous: Reserve default CMA heap")
introduced a bug where dma_heap_cma_register_heap() is called with
a NULL pointer when dma_contiguous_reserve_area() fails to reserve
the CMA area.
When dma_contiguous_reserve_area() fails, dma_contiguous_default_area
remains NULL (initialized as a global variable), but the code doesn't
check the return value and proceeds to call dma_heap_cma_register_heap()
with this NULL pointer.
Later during boot, add_cma_heaps() iterates through the dma_areas[]
array and attempts to register heaps. When it encounters the NULL
pointer stored by the earlier call, it crashes in __add_cma_heap()
-> dma_heap_add() when trying to dereference the NULL CMA pointer.
The crash manifests as:
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000038
...
Call trace:
dma_heap_add+0x40/0x2b0
__add_cma_heap+0x80/0xe0
add_cma_heaps+0x64/0xb0
do_one_initcall+0x60/0x318
kernel_init_freeable+0x260/0x2f0
kernel_init+0x2c/0x168
ret_from_fork+0x10/0x20
Fix this by checking the return value of dma_contiguous_reserve_area()
and only calling dma_heap_cma_register_heap() when the reservation
succeeds.
Fixes: 8f1fc1bf1a3d ("dma: contiguous: Reserve default CMA heap")
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260129181317.2429196-1-sdonthineni@nvidia.com
Currently, dma_alloc_from_pool() unconditionally warns and dumps a stack
trace when an allocation fails, with the message "Failed to get suitable
pool".
This conflates two distinct failure modes:
1. Configuration error: No atomic pool is available for the requested
DMA mask (a fundamental system setup issue)
2. Resource Exhaustion: A suitable pool exists but is currently full (a
recoverable runtime state)
This lack of distinction prevents drivers from using __GFP_NOWARN to
suppress error messages during temporary pressure spikes, such as when
awaiting synchronous reclaim of descriptors.
Refactor the error handling to distinguish these cases:
- If no suitable pool is found, keep the unconditional WARN regarding
the missing pool.
- If a pool was found but is exhausted, respect __GFP_NOWARN and update
the warning message to explicitly state "DMA pool exhausted".
Fixes: 9420139f516d ("dma-pool: fix coherent pool allocations for IOMMU mappings")
Signed-off-by: Sai Sree Kartheek Adivi <s-adivi@ti.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260128133554.3056582-1-s-adivi@ti.com
When initializing the default cma region, the "cma=" kernel parameter
takes priority over a DT defined linux,cma-default region. Hence, give
the reserved_mem framework the ability to detect this so that the DT
defined cma region can skip initialization accordingly.
Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@oss.qualcomm.com>
Tested-by: Joy Zou <joy.zou@nxp.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Fixes: 2c223f7239f3 ("of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()")
Link: https://lore.kernel.org/r/20251210002027.1171519-1-oreoluwa.babatunde@oss.qualcomm.com
[mszyprow: rebased onto v6.19-rc1, added fixes tags, added a stub for
cma_skip_dt_default_reserved_mem() if no CONFIG_DMA_CMA is set]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
On smaller systems, e.g. embedded arm64, it is common for all memory to end up in ZONE_DMA32 or even ZONE_DMA. In such cases it is redundant to allocate a nominal pool for an empty higher zone that just ends up coming from a lower zone that should already have its own pool anyway. We already have logic to skip allocating a ZONE_DMA pool when that is empty, so generalise that to save memory in the case of other zones too. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com> Reviewed-by: Baoquan He <bhe@redhat.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/8ab8d8a620dee0109f33f5cb63d6bfeed35aac37.1768230104.git.robin.murphy@arm.com
If CONFIG_ZONE_DMA32 is enabled, but we have not allocated the corresponding atomic_pool_dma32, dma_guess_pool() may return the NULL value of that and fail a GFP_DMA32 allocation without trying to fall back to other pools which may exist. Furthermore, if no GFP_DMA pool exists, it is preferable to try GFP_DMA32 rather than immediately fall back to GFP_KERNEL with even less chance of success. Improve matters by encoding an explicit order of pool preference for each flag. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com> Reviewed-by: Baoquan He <bhe@redhat.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/c846b1a2f43295cac926c7af2ce907f62baec518.1768230104.git.robin.murphy@arm.com
Pull dma-mapping fixes from Marek Szyprowski: - last minute fix for missing parenthesis in recently merged code (Hans de Goede) - removal of excessive, non-fatal warnings (Dave Kleikamp) * tag 'dma-mapping-6.19-2025-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: dma-mapping: Fix DMA_BIT_MASK() macro being broken dma/pool: eliminate alloc_pages warning in atomic_pool_expand
atomic_pool_expand iteratively tries the allocation while decrementing
the page order. There is no need to issue a warning if an attempted
allocation fails.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Fixes: d7e673ec2c8e ("dma-pool: Only allocate from CMA when in same memory zone")
[mszyprow: fixed typo]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20251202152810.142370-1-dave.kleikamp@oracle.com
Pull dma-mapping updates from Marek Szyprowski: - More DMA mapping API refactoring to physical addresses as the primary interface instead of page+offset parameters. This time dma_map_ops callbacks are converted to physical addresses, what in turn results also in some simplification of architecture specific code (Leon Romanovsky and Jason Gunthorpe) - Clarify that dma_map_benchmark is not a kernel self-test, but standalone tool (Qinxin Xia) * tag 'dma-mapping-6.19-2025-12-05' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: dma-mapping: remove unused map_page callback xen: swiotlb: Convert mapping routine to rely on physical address x86: Use physical address for DMA mapping sparc: Use physical address DMA mapping powerpc: Convert to physical address DMA mapping parisc: Convert DMA map_page to map_phys interface MIPS/jazzdma: Provide physical address directly alpha: Convert mapping routine to rely on physical address dma-mapping: remove unused mapping resource callbacks xen: swiotlb: Switch to physical address mapping callbacks ARM: dma-mapping: Switch to physical address mapping callbacks ARM: dma-mapping: Reduce struct page exposure in arch_sync_dma*() dma-mapping: convert dummy ops to physical address mapping dma-mapping: prepare dma_map_ops to conversion to physical address tools/dma: move dma_map_benchmark from selftests to tools/dma
Pull MM updates from Andrew Morton:
"__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki)
Rework the vmalloc() code to support non-blocking allocations
(GFP_ATOIC, GFP_NOWAIT)
"ksm: fix exec/fork inheritance" (xu xin)
Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not
inherited across fork/exec
"mm/zswap: misc cleanup of code and documentations" (SeongJae Park)
Some light maintenance work on the zswap code
"mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira)
Enhance the /sys/kernel/debug/page_owner debug feature by adding
unique identifiers to differentiate the various stack traces so
that userspace monitoring tools can better match stack traces over
time
"mm/page_alloc: pcp->batch cleanups" (Joshua Hahn)
Minor alterations to the page allocator's per-cpu-pages feature
"Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra)
Address a scalability issue in userfaultfd's UFFDIO_MOVE operation
"kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov)
"drivers/base/node: fold node register and unregister functions" (Donet Tom)
Clean up the NUMA node handling code a little
"mm: some optimizations for prot numa" (Kefeng Wang)
Cleanups and small optimizations to the NUMA allocation hinting
code
"mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn)
Address long lock hold times at boot on large machines. These were
causing (harmless) softlockup warnings
"optimize the logic for handling dirty file folios during reclaim" (Baolin Wang)
Remove some now-unnecessary work from page reclaim
"mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park)
Enhance the DAMOS auto-tuning feature
"mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan)
Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace
configuration
"expand mmap_prepare functionality, port more users" (Lorenzo Stoakes)
Enhance the new(ish) file_operations.mmap_prepare() method and port
additional callsites from the old ->mmap() over to ->mmap_prepare()
"Fix stale IOTLB entries for kernel address space" (Lu Baolu)
Fix a bug (and possible security issue on non-x86) in the IOMMU
code. In some situations the IOMMU could be left hanging onto a
stale kernel pagetable entry
"mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang)
Clean up and optimize the folio splitting code
"mm, swap: misc cleanup and bugfix" (Kairui Song)
Some cleanups and a minor fix in the swap discard code
"mm/damon: misc documentation fixups" (SeongJae Park)
"mm/damon: support pin-point targets removal" (SeongJae Park)
Permit userspace to remove a specific monitoring target in the
middle of the current targets list
"mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo)
A couple of cleanups related to mm header file inclusion
"mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He)
improve the selection of swap devices for NUMA machines
"mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista)
Change the memory block labels from macros to enums so they will
appear in kernel debug info
"ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes)
Address an inefficiency when KSM unmerges an address range
"mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park)
Fix leaks and unhandled malloc() failures in DAMON userspace unit
tests
"some cleanups for pageout()" (Baolin Wang)
Clean up a couple of minor things in the page scanner's
writeback-for-eviction code
"mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu)
Move hugetlb's sysfs/sysctl handling code into a new file
"introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes)
Make the VMA guard regions available in /proc/pid/smaps and
improves the mergeability of guarded VMAs
"mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes)
Reduce mmap lock contention for callers performing VMA guard region
operations
"vma_start_write_killable" (Matthew Wilcox)
Start work on permitting applications to be killed when they are
waiting on a read_lock on the VMA lock
"mm/damon/tests: add more tests for online parameters commit" (SeongJae Park)
Add additional userspace testing of DAMON's "commit" feature
"mm/damon: misc cleanups" (SeongJae Park)
"make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes)
Address the possible loss of a VMA's VM_SOFTDIRTY flag when that
VMA is merged with another
"mm: support device-private THP" (Balbir Singh)
Introduce support for Transparent Huge Page (THP) migration in zone
device-private memory
"Optimize folio split in memory failure" (Zi Yan)
"mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang)
Some more cleanups in the folio splitting code
"mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes)
Clean up our handling of pagetable leaf entries by introducing the
concept of 'software leaf entries', of type softleaf_t
"reparent the THP split queue" (Muchun Song)
Reparent the THP split queue to its parent memcg. This is in
preparation for addressing the long-standing "dying memcg" problem,
wherein dead memcg's linger for too long, consuming memory
resources
"unify PMD scan results and remove redundant cleanup" (Wei Yang)
A little cleanup in the hugepage collapse code
"zram: introduce writeback bio batching" (Sergey Senozhatsky)
Improve zram writeback efficiency by introducing batched bio
writeback support
"memcg: cleanup the memcg stats interfaces" (Shakeel Butt)
Clean up our handling of the interrupt safety of some memcg stats
"make vmalloc gfp flags usage more apparent" (Vishal Moola)
Clean up vmalloc's handling of incoming GFP flags
"mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang)
Teach soft dirty and userfaultfd write protect tracking to use
RISC-V's Svrsw60t59b extension
"mm: swap: small fixes and comment cleanups" (Youngjun Park)
Fix a small bug and clean up some of the swap code
"initial work on making VMA flags a bitmap" (Lorenzo Stoakes)
Start work on converting the vma struct's flags to a bitmap, so we
stop running out of them, especially on 32-bit
"mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park)
Address a possible bug in the swap discard code and clean things
up a little
[ This merge also reverts commit ebb9aeb980e5 ("vfio/nvgrace-gpu:
register device memory for poison handling") because it looks
broken to me, I've asked for clarification - Linus ]
* tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm: fix vma_start_write_killable() signal handling
mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate
mm/swapfile: fix list iteration when next node is removed during discard
fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling
mm/kfence: add reboot notifier to disable KFENCE on shutdown
memcg: remove inc/dec_lruvec_kmem_state helpers
selftests/mm/uffd: initialize char variable to Null
mm: fix DEBUG_RODATA_TEST indentation in Kconfig
mm: introduce VMA flags bitmap type
tools/testing/vma: eliminate dependency on vma->__vm_flags
mm: simplify and rename mm flags function for clarity
mm: declare VMA flags by bit
zram: fix a spelling mistake
mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity
mm/vmscan: skip increasing kswapd_failures when reclaim was boosted
pagemap: update BUDDY flag documentation
mm: swap: remove scan_swap_map_slots() references from comments
mm: swap: change swap_alloc_slow() to void
mm, swap: remove redundant comment for read_swap_cache_async
mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational
...
Pull VFIO updates from Alex Williamson: - Move libvfio selftest artifacts in preparation of more tightly coupled integration with KVM selftests (David Matlack) - Fix comment typo in mtty driver (Chu Guangqing) - Support for new hardware revision in the hisi_acc vfio-pci variant driver where the migration registers can now be accessed via the PF. When enabled for this support, the full BAR can be exposed to the user (Longfang Liu) - Fix vfio cdev support for VF token passing, using the correct size for the kernel structure, thereby actually allowing userspace to provide a non-zero UUID token. Also set the match token callback for the hisi_acc, fixing VF token support for this this vfio-pci variant driver (Raghavendra Rao Ananta) - Introduce internal callbacks on vfio devices to simplify and consolidate duplicate code for generating VFIO_DEVICE_GET_REGION_INFO data, removing various ioctl intercepts with a more structured solution (Jason Gunthorpe) - Introduce dma-buf support for vfio-pci devices, allowing MMIO regions to be exposed through dma-buf objects with lifecycle managed through move operations. This enables low-level interactions such as a vfio-pci based SPDK drivers interacting directly with dma-buf capable RDMA devices to enable peer-to-peer operations. IOMMUFD is also now able to build upon this support to fill a long standing feature gap versus the legacy vfio type1 IOMMU backend with an implementation of P2P support for VM use cases that better manages the lifecycle of the P2P mapping (Leon Romanovsky, Jason Gunthorpe, Vivek Kasireddy) - Convert eventfd triggering for error and request signals to use RCU mechanisms in order to avoid a 3-way lockdep reported deadlock issue (Alex Williamson) - Fix a 32-bit overflow introduced via dma-buf support manifesting with large DMA buffers (Alex Mastro) - Convert nvgrace-gpu vfio-pci variant driver to insert mappings on fault rather than at mmap time. This conversion serves both to make use of huge PFNMAPs but also to both avoid corrected RAS events during reset by now being subject to vfio-pci-core's use of unmap_mapping_range(), and to enable a device readiness test after reset (Ankit Agrawal) - Refactoring of vfio selftests to support multi-device tests and split code to provide better separation between IOMMU and device objects. This work also enables a new test suite addition to measure parallel device initialization latency (David Matlack) * tag 'vfio-v6.19-rc1' of https://github.com/awilliam/linux-vfio: (65 commits) vfio: selftests: Add vfio_pci_device_init_perf_test vfio: selftests: Eliminate INVALID_IOVA vfio: selftests: Split libvfio.h into separate header files vfio: selftests: Move vfio_selftests_*() helpers into libvfio.c vfio: selftests: Rename vfio_util.h to libvfio.h vfio: selftests: Stop passing device for IOMMU operations vfio: selftests: Move IOVA allocator into iova_allocator.c vfio: selftests: Move IOMMU library code into iommu.c vfio: selftests: Rename struct vfio_dma_region to dma_region vfio: selftests: Upgrade driver logging to dev_err() vfio: selftests: Prefix logs with device BDF where relevant vfio: selftests: Eliminate overly chatty logging vfio: selftests: Support multiple devices in the same container/iommufd vfio: selftests: Introduce struct iommu vfio: selftests: Rename struct vfio_iommu_mode to iommu_mode vfio: selftests: Allow passing multiple BDFs on the command line vfio: selftests: Split run.sh into separate scripts vfio: selftests: Move run.sh into scripts directory vfio/nvgrace-gpu: wait for the GPU mem to be ready vfio/nvgrace-gpu: Inform devmem unmapped after reset ...