kernel/linux.git/lib/test_vmalloc.c, branch v6.6.132

lib/test_vmalloc.c: avoid garbage in page array

2023-06-12T18:31:51+00:00

It turns out that alloc_pages_bulk_array() does not treat the page_array parameter as an output parameter, but rather reads the array and skips any entries that have already been allocated. This is somewhat unexpected and breaks this test, as we allocate the pages array uninitialised on the assumption it will be overwritten. As a result, the test was referencing uninitialised data and causing the PFN to not be valid and thus a WARN_ON() followed by a null pointer deref and panic. In addition, this is an array of pointers not of struct page objects, so we need only allocate an array with elements of pointer size. We solve both problems by simply using kcalloc() and referencing sizeof(struct page *) rather than sizeof(struct page). Link: https://lkml.kernel.org/r/20230524082424.10022-1-lstoakes@gmail.com Fixes: 869cb29a61a1 ("lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case") Signed-off-by: Lorenzo Stoakes Reviewed-by: Uladzislau Rezki (Sony) Reviewed-by: Baoquan He Cc: Christoph Hellwig Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-04-28T02:42:02+00:00

Pull MM updates from Andrew Morton: - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of switching from a user process to a kernel thread. - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav. - zsmalloc performance improvements from Sergey Senozhatsky. - Yue Zhao has found and fixed some data race issues around the alteration of memcg userspace tunables. - VFS rationalizations from Christoph Hellwig: - removal of most of the callers of write_one_page() - make __filemap_get_folio()'s return value more useful - Luis Chamberlain has changed tmpfs so it no longer requires swap backing. Use `mount -o noswap'. - Qi Zheng has made the slab shrinkers operate locklessly, providing some scalability benefits. - Keith Busch has improved dmapool's performance, making part of its operations O(1) rather than O(n). - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd, permitting userspace to wr-protect anon memory unpopulated ptes. - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather than exclusive, and has fixed a bunch of errors which were caused by its unintuitive meaning. - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature, which causes minor faults to install a write-protected pte. - Vlastimil Babka has done some maintenance work on vma_merge(): cleanups to the kernel code and improvements to our userspace test harness. - Cleanups to do_fault_around() by Lorenzo Stoakes. - Mike Rapoport has moved a lot of initialization code out of various mm/ files and into mm/mm_init.c. - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for DRM, but DRM doesn't use it any more. - Lorenzo has also coverted read_kcore() and vread() to use iterators and has thereby removed the use of bounce buffers in some cases. - Lorenzo has also contributed further cleanups of vma_merge(). - Chaitanya Prakash provides some fixes to the mmap selftesting code. - Matthew Wilcox changes xfs and afs so they no longer take sleeping locks in ->map_page(), a step towards RCUification of pagefaults. - Suren Baghdasaryan has improved mmap_lock scalability by switching to per-VMA locking. - Frederic Weisbecker has reworked the percpu cache draining so that it no longer causes latency glitches on cpu isolated workloads. - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig logic. - Liu Shixin has changed zswap's initialization so we no longer waste a chunk of memory if zswap is not being used. - Yosry Ahmed has improved the performance of memcg statistics flushing. - David Stevens has fixed several issues involving khugepaged, userfaultfd and shmem. - Christoph Hellwig has provided some cleanup work to zram's IO-related code paths. - David Hildenbrand has fixed up some issues in the selftest code's testing of our pte state changing. - Pankaj Raghav has made page_endio() unneeded and has removed it. - Peter Xu contributed some rationalizations of the userfaultfd selftests. - Yosry Ahmed has fixed an issue around memcg's page recalim accounting. - Chaitanya Prakash has fixed some arm-related issues in the selftests/mm code. - Longlong Xia has improved the way in which KSM handles hwpoisoned pages. - Peter Xu fixes a few issues with uffd-wp at fork() time. - Stefan Roesch has changed KSM so that it may now be used on a per-process and per-cgroup basis. * tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm,unmap: avoid flushing TLB in batch if PTE is inaccessible shmem: restrict noswap option to initial user namespace mm/khugepaged: fix conflicting mods to collapse_file() sparse: remove unnecessary 0 values from rc mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area() hugetlb: pte_alloc_huge() to replace huge pte_alloc_map() maple_tree: fix allocation in mas_sparse_area() mm: do not increment pgfault stats when page fault handler retries zsmalloc: allow only one active pool compaction context selftests/mm: add new selftests for KSM mm: add new KSM process and sysfs knobs mm: add new api to enable ksm per process mm: shrinkers: fix debugfs file permissions mm: don't check VMA write permissions if the PTE/PMD indicates write permissions migrate_pages_batch: fix statistics for longterm pin retry userfaultfd: use helper function range_in_vma() lib/show_mem.c: use for_each_populated_zone() simplify code mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list() fs/buffer: convert create_page_buffers to folio_create_buffers fs/buffer: add folio_create_empty_buffers helper ...

lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case

2023-04-18T23:29:47+00:00

Add vm_map_ram()/vm_unmap_ram() test case to our stress test-suite. [akpm@linux-foundation.org: fix whitespace, per Lorenzo] Link: https://lkml.kernel.org/r/20230330190639.431589-2-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Lorenzo Stoakes Reviewed-by: Baoquan He Cc: Christoph Hellwig Cc: Dave Chinner Cc: Matthew Wilcox (Oracle) Cc: Oleksiy Avramchenko Signed-off-by: Andrew Morton

lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()

2023-04-05T13:48:03+00:00

The kvfree_rcu() macro's single-argument form is deprecated. Therefore switch to the new kvfree_rcu_mightsleep() variant. The goal is to avoid accidental use of the single-argument forms, which can introduce functionality bugs in atomic contexts and latency bugs in non-atomic contexts. Acked-by: Joel Fernandes (Google) Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Paul E. McKenney Signed-off-by: Joel Fernandes (Google)

lib/test_vmalloc.c: add parameter use_huge for fix_size_alloc_test

2023-01-19T01:12:41+00:00

Add a parameter `use_huge' for fix_size_alloc_test(), which can be used to test allocation vie vmalloc_huge for both functionality and performance. Link: https://lkml.kernel.org/r/20221212055657.698420-1-panqinglin2020@iscas.ac.cn Signed-off-by: Qinglin Pan Cc: "Uladzislau Rezki (Sony)" Signed-off-by: Andrew Morton

treewide: use get_random_u32_inclusive() when possible

2022-11-18T01:18:02+00:00

These cases were done with this Coccinelle: @@ expression H; expression L; @@ - (get_random_u32_below(H) + L) + get_random_u32_inclusive(L, H + L - 1) @@ expression H; expression L; expression E; @@ get_random_u32_inclusive(L, H - + E - - E ) @@ expression H; expression L; expression E; @@ get_random_u32_inclusive(L, H - - E - + E ) @@ expression H; expression L; expression E; expression F; @@ get_random_u32_inclusive(L, H - - E + F - + E ) @@ expression H; expression L; expression E; expression F; @@ get_random_u32_inclusive(L, H - + E + F - - E ) And then subsequently cleaned up by hand, with several automatic cases rejected if it didn't make sense contextually. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Reviewed-by: Jason Gunthorpe # for infiniband Signed-off-by: Jason A. Donenfeld

treewide: use get_random_u32_below() instead of deprecated function

2022-11-18T01:15:15+00:00

This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Acked-by: Darrick J. Wong # for xfs Reviewed-by: SeongJae Park # for damon Reviewed-by: Jason Gunthorpe # for infiniband Reviewed-by: Russell King (Oracle) # for arm Acked-by: Ulf Hansson # for mmc Signed-off-by: Jason A. Donenfeld

treewide: use get_random_{u8,u16}() when possible, part 2

2022-10-11T23:42:58+00:00

Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value, simply use the get_random_{u8,u16}() functions, which are faster than wasting the additional bytes from a 32-bit value. This was done by hand, identifying all of the places where one of the random integer functions was used in a non-32-bit context. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Acked-by: Jakub Kicinski Acked-by: Heiko Carstens # for s390 Signed-off-by: Jason A. Donenfeld

treewide: use prandom_u32_max() when possible, part 2

2022-10-11T23:42:58+00:00

Rather than incurring a division or requesting too many random bytes for the given range, use the prandom_u32_max() function, which only takes the minimum required bytes from the RNG and avoids divisions. This was done by hand, covering things that coccinelle could not do on its own. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: Jan Kara # for ext2, ext4, and sbitmap Acked-by: Jakub Kicinski Signed-off-by: Jason A. Donenfeld

lib/test_vmalloc: switch to prandom_u32()

2022-07-04T01:08:42+00:00

A get_random_bytes() function can cause a high contention if it is called across CPUs simultaneously. Because it shares one lock per all CPUs: class name con-bounces contentions waittime-min waittime-max waittime-total waittime-avg acq-bounces acquisitions holdtime-min holdtime-max holdtime-total holdtime-avg &crng->lock: 663145 665886 0.05 8.85 261966.66 0.39 7188152 13731279 0.04 11.89 2181582.30 0.16 ----------- &crng->lock 307835 [<00000000acba59cd>] _extract_crng+0x48/0x90 &crng->lock 358051 [<00000000f0075abc>] _crng_backtrack_protect+0x32/0x90 ----------- &crng->lock 234241 [<00000000f0075abc>] _crng_backtrack_protect+0x32/0x90 &crng->lock 431645 [<00000000acba59cd>] _extract_crng+0x48/0x90 Switch from the get_random_bytes() to prandom_u32() that does not have any internal contention when a random value is needed for the tests. The reason is to minimize CPU cycles introduced by the test-suite itself from the vmalloc performance metrics. Link: https://lkml.kernel.org/r/20220607093449.3100-6-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Cc: Christoph Hellwig Cc: Matthew Wilcox Cc: Nicholas Piggin Cc: Oleksiy Avramchenko Signed-off-by: Andrew Morton