- Sep 02, 2021
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Linus Torvalds authored
'kvmalloc()' is a convenience function for people who want to do a kmalloc() but fall back on vmalloc() if there aren't enough physically contiguous pages, or if the allocation is larger than what kmalloc() supports. However, let's make sure it doesn't get _too_ easy to do crazy things with it. In particular, don't allow big allocations that could be due to integer overflow or underflow. So make sure the allocation size fits in an 'int', to protect against trivial integer conversion issues. Acked-by:
Willy Tarreau <w@1wt.eu> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- Aug 09, 2021
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Dave Chinner authored
During log recovery of an XFS filesystem with 64kB directory buffers, rebuilding a buffer split across two log records results in a memory allocation warning from krealloc like this: xfs filesystem being mounted at /mnt/scratch supports timestamps until 2038 (0x7fffffff) XFS (dm-0): Unmounting Filesystem XFS (dm-0): Mounting V5 Filesystem XFS (dm-0): Starting recovery (logdev: internal) ------------[ cut here ]------------ WARNING: CPU: 5 PID: 3435170 at mm/page_alloc.c:3539 get_page_from_freelist+0xdee/0xe40 ..... RIP: 0010:get_page_from_freelist+0xdee/0xe40 Call Trace: ? complete+0x3f/0x50 __alloc_pages+0x16f/0x300 alloc_pages+0x87/0x110 kmalloc_order+0x2c/0x90 kmalloc_order_trace+0x1d/0x90 __kmalloc_track_caller+0x215/0x270 ? xlog_recover_add_to_cont_trans+0x63/0x1f0 krealloc+0x54/0xb0 xlog_recover_add_to_cont_trans+0x63/0x1f0 xlog_recovery_process_trans+0xc1/0xd0 xlog_recover_process_ophdr+0x86/0x130 xlog_recover_process_data+0x9f/0x160 xlog_recover_process+0xa2/0x120 xlog_do_recovery_pass+0x40b/0x7d0 ? __irq_work_queue_local+0x4f/0x60 ? irq_work_queue+0x3a/0x50 xlog_do_log_recovery+0x70/0x150 xlog_do_recover+0x38/0x1d0 xlog_recover+0xd8/0x170 xfs_log_mount+0x181/0x300 xfs_mountfs+0x4a1/0x9b0 xfs_fs_fill_super+0x3c0/0x7b0 get_tree_bdev+0x171/0x270 ? suffix_kstrtoint.constprop.0+0xf0/0xf0 xfs_fs_get_tree+0x15/0x20 vfs_get_tree+0x24/0xc0 path_mount+0x2f5/0xaf0 __x64_sys_mount+0x108/0x140 do_syscall_64+0x3a/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Essentially, we are taking a multi-order allocation from kmem_alloc() (which has an open coded no fail, no warn loop) and then reallocating it out to 64kB using krealloc(__GFP_NOFAIL) and that is then triggering the above warning. This is a regression caused by converting this code from an open coded no fail/no warn reallocation loop to using __GFP_NOFAIL. What we actually need here is kvrealloc(), so that if contiguous page allocation fails we fall back to vmalloc() and we don't get nasty warnings happening in XFS. Fixes: 771915c4 ("xfs: remove kmem_realloc()") Signed-off-by:
Dave Chinner <dchinner@redhat.com> Acked-by:
Mel Gorman <mgorman@techsingularity.net> Reviewed-by:
Darrick J. Wong <djwong@kernel.org> Signed-off-by:
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- Jul 12, 2021
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Matthew Wilcox (Oracle) authored
Rewrite copy_huge_page() and move it into mm/util.c so it's always available. Fixes an exposure of uninitialised memory on configurations with HUGETLB and UFFD enabled and MIGRATION disabled. Fixes: 8cc5fcbb ("mm, hugetlb: fix racy resv_huge_pages underflow on UFFDIO_COPY") Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by:
Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by:
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- Jul 01, 2021
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David Hildenbrand authored
A driver might set a page logically offline -- PageOffline() -- and turn the page inaccessible in the hypervisor; after that, access to page content can be fatal. One example is virtio-mem; while unplugged memory -- marked as PageOffline() can currently be read in the hypervisor, this will no longer be the case in the future; for example, when having a virtio-mem device backed by huge pages in the hypervisor. Some special PFN walkers -- i.e., /proc/kcore -- read content of random pages after checking PageOffline(); however, these PFN walkers can race with drivers that set PageOffline(). Let's introduce page_offline_(begin|end|freeze|thaw) for synchronizing. page_offline_freeze()/page_offline_thaw() allows for a subsystem to synchronize with such drivers, achieving that a page cannot be set PageOffline() while frozen. page_offline_begin()/page_offline_end() is used by drivers that care about such races when setting a page PageOffline(). For simplicity, use a rwsem for now; neither drivers nor users are performance sensitive. Link: https://lkml.kernel.org/r/20210526093041.8800-5-david@redhat.com Signed-off-by:
David Hildenbrand <david@redhat.com> Acked-by:
Michal Hocko <mhocko@suse.com> Reviewed-by:
Mike Rapoport <rppt@linux.ibm.com> Reviewed-by:
Oscar Salvador <osalvador@suse.de> Cc: Aili Yao <yaoaili@kingsoft.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Jiri Bohac <jbohac@suse.cz> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Roman Gushchin <guro@fb.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Steven Price <steven.price@arm.com> Cc: Wei Liu <wei.liu@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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- May 10, 2021
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Maninder Singh authored
This commit adds enables a stack dump for the last free of an object: slab kmalloc-64 start c8ab0140 data offset 64 pointer offset 0 size 64 allocated at meminfo_proc_show+0x40/0x4fc [ 20.192078] meminfo_proc_show+0x40/0x4fc [ 20.192263] seq_read_iter+0x18c/0x4c4 [ 20.192430] proc_reg_read_iter+0x84/0xac [ 20.192617] generic_file_splice_read+0xe8/0x17c [ 20.192816] splice_direct_to_actor+0xb8/0x290 [ 20.193008] do_splice_direct+0xa0/0xe0 [ 20.193185] do_sendfile+0x2d0/0x438 [ 20.193345] sys_sendfile64+0x12c/0x140 [ 20.193523] ret_fast_syscall+0x0/0x58 [ 20.193695] 0xbeeacde4 [ 20.193822] Free path: [ 20.193935] meminfo_proc_show+0x5c/0x4fc [ 20.194115] seq_read_iter+0x18c/0x4c4 [ 20.194285] proc_reg_read_iter+0x84/0xac [ 20.194475] generic_file_splice_read+0xe8/0x17c [ 20.194685] splice_direct_to_actor+0xb8/0x290 [ 20.194870] do_splice_direct+0xa0/0xe0 [ 20.195014] do_sendfile+0x2d0/0x438 [ 20.195174] sys_sendfile64+0x12c/0x140 [ 20.195336] ret_fast_syscall+0x0/0x58 [ 20.195491] 0xbeeacde4 Acked-by:
Vlastimil Babka <vbabka@suse.cz> Co-developed-by:
Vaneet Narang <v.narang@samsung.com> Signed-off-by:
Maninder Singh <maninder1.s@samsung.com> Signed-off-by:
Paul E. McKenney <paulmck@kernel.org>
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- May 05, 2021
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Bhaskar Chowdhury authored
s/condtion/condition/ Link: https://lkml.kernel.org/r/20210317033439.3429411-1-unixbhaskar@gmail.com Signed-off-by:
Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by:
Randy Dunlap <rdunlap@infradead.org> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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Joe Perches authored
Simplify the code by using a temporary and reduce the object size by using a single call to pr_cont(). Reverse a test and unindent a block too. $ size mm/util.o* (defconfig x86-64) text data bss dec hex filename 7419 372 40 7831 1e97 mm/util.o.new 7477 372 40 7889 1ed1 mm/util.o.old Link: https://lkml.kernel.org/r/a6e105886338f68afd35f7a13d73bcf06b0cc732.camel@perches.com Signed-off-by:
Joe Perches <joe@perches.com> Reviewed-by:
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- Apr 30, 2021
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Matthew Wilcox (Oracle) authored
page_mapping_file() is only used by some architectures, and then it is usually only used in one place. Make it a static inline function so other architectures don't have to carry this dead code. Link: https://lkml.kernel.org/r/20210317123011.350118-1-willy@infradead.org Signed-off-by:
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- Mar 08, 2021
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Paul E. McKenney authored
This commit adds a few crude tests for mem_dump_obj() to rcutorture runs. Just to prevent bitrot, you understand! Signed-off-by: -
Paul E. McKenney authored
The mem_dump_obj() functionality adds a few hundred bytes, which is a small price to pay. Except on kernels built with CONFIG_PRINTK=n, in which mem_dump_obj() messages will be suppressed. This commit therefore makes mem_dump_obj() be a static inline empty function on kernels built with CONFIG_PRINTK=n and excludes all of its support functions as well. This avoids kernel bloat on systems that cannot use mem_dump_obj(). Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <linux-mm@kvack.org> Suggested-by:
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- Jan 22, 2021
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Paul E. McKenney authored
This commit adds vmalloc() support to mem_dump_obj(). Note that the vmalloc_dump_obj() function combines the checking and dumping, in contrast with the split between kmem_valid_obj() and kmem_dump_obj(). The reason for the difference is that the checking in the vmalloc() case involves acquiring a global lock, and redundant acquisitions of global locks should be avoided, even on not-so-fast paths. Note that this change causes on-stack variables to be reported as vmalloc() storage from kernel_clone() or similar, depending on the degree of inlining that your compiler does. This is likely more helpful than the earlier "non-paged (local) memory". Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <linux-mm@kvack.org> Reported-by:
Andrii Nakryiko <andrii@kernel.org> Acked-by:
Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by:
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Paul E. McKenney authored
This commit makes mem_dump_obj() call out NULL and zero-sized pointers specially instead of classifying them as non-paged memory. Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <linux-mm@kvack.org> Reported-by:
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Paul E. McKenney authored
There are kernel facilities such as per-CPU reference counts that give error messages in generic handlers or callbacks, whose messages are unenlightening. In the case of per-CPU reference-count underflow, this is not a problem when creating a new use of this facility because in that case the bug is almost certainly in the code implementing that new use. However, trouble arises when deploying across many systems, which might exercise corner cases that were not seen during development and testing. Here, it would be really nice to get some kind of hint as to which of several uses the underflow was caused by. This commit therefore exposes a mem_dump_obj() function that takes a pointer to memory (which must still be allocated if it has been dynamically allocated) and prints available information on where that memory came from. This pointer can reference the middle of the block as well as the beginning of the block, as needed by things like RCU callback functions and timer handlers that might not know where the beginning of the memory block is. These functions and handlers can use mem_dump_obj() to print out better hints as to where the problem might lie. The information printed can depend on kernel configuration. For example, the allocation return address can be printed only for slab and slub, and even then only when the necessary debug has been enabled. For slab, build with CONFIG_DEBUG_SLAB=y, and either use sizes with ample space to the next power of two or use the SLAB_STORE_USER when creating the kmem_cache structure. For slub, build with CONFIG_SLUB_DEBUG=y and boot with slub_debug=U, or pass SLAB_STORE_USER to kmem_cache_create() if more focused use is desired. Also for slub, use CONFIG_STACKTRACE to enable printing of the allocation-time stack trace. Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <linux-mm@kvack.org> Reported-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by:
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- Nov 19, 2020
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Christian König authored
Add the new vma_set_file() function to allow changing vma->vm_file with the necessary refcount dance. v2: add more users of this. v3: add missing EXPORT_SYMBOL, rebase on mmap cleanup, add comments why we drop the reference on two occasions. v4: make it clear that changing an anonymous vma is illegal. v5: move vma_set_file to mm/util.c Signed-off-by:Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v2) Reviewed-by:
Jason Gunthorpe <jgg@nvidia.com> Acked-by:
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- Oct 16, 2020
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Bartosz Golaszewski authored
Memory allocated with kstrdup_const() must not be passed to regular krealloc() as it is not aware of the possibility of the chunk residing in .rodata. Since there are no potential users of krealloc_const() at the moment, let's just update the doc to make it explicit. Signed-off-by:
Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by:
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- Sep 04, 2020
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Catalin Marinas authored
When the Memory Tagging Extension is enabled, two pages are identical only if both their data and tags are identical. Make the generic memcmp_pages() a __weak function and add an arm64-specific implementation which returns non-zero if any of the two pages contain valid MTE tags (PG_mte_tagged set). There isn't much benefit in comparing the tags of two pages since these are normally used for heap allocations and likely to differ anyway. Co-developed-by:
Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org>
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- Aug 07, 2020
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Peter Collingbourne authored
The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by:
Peter Collingbourne <pcc@google.com> Signed-off-by:
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Feng Tang authored
When checking a performance change for will-it-scale scalability mmap test [1], we found very high lock contention for spinlock of percpu counter 'vm_committed_as': 94.14% 0.35% [kernel.kallsyms] [k] _raw_spin_lock_irqsave 48.21% _raw_spin_lock_irqsave;percpu_counter_add_batch;__vm_enough_memory;mmap_region;do_mmap; 45.91% _raw_spin_lock_irqsave;percpu_counter_add_batch;__do_munmap; Actually this heavy lock contention is not always necessary. The 'vm_committed_as' needs to be very precise when the strict OVERCOMMIT_NEVER policy is set, which requires a rather small batch number for the percpu counter. So keep 'batch' number unchanged for strict OVERCOMMIT_NEVER policy, and lift it to 64X for OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS policies. Also add a sysctl handler to adjust it when the policy is reconfigured. Benchmark with the same testcase in [1] shows 53% improvement on a 8C/16T desktop, and 2097%(20X) on a 4S/72C/144T server. We tested with test platforms in 0day (server, desktop and laptop), and 80%+ platforms shows improvements with that test. And whether it shows improvements depends on if the test mmap size is bigger than the batch number computed. And if the lift is 16X, 1/3 of the platforms will show improvements, though it should help the mmap/unmap usage generally, as Michal Hocko mentioned: : I believe that there are non-synthetic worklaods which would benefit from : a larger batch. E.g. large in memory databases which do large mmaps : during startups from multiple threads. [1] https://lore.kernel.org/lkml/20200305062138.GI5972@shao2-debian/ Signed-off-by:Feng Tang <feng.tang@intel.com> Signed-off-by:
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Feng Tang authored
percpu_counter_sum_positive() will provide more accurate info. As with percpu_counter_read_positive(), in worst case the deviation could be 'batch * nr_cpus', which is totalram_pages/256 for now, and will be more when the batch gets enlarged. Its time cost is about 800 nanoseconds on a 2C/4T platform and 2~3 microseconds on a 2S/36C/72T Skylake server in normal case, and in worst case where vm_committed_as's spinlock is under severe contention, it costs 30~40 microseconds for the 2S/36C/72T Skylake sever, which should be fine for its only two users: /proc/meminfo and HyperV balloon driver's status trace per second. Signed-off-by:
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- Jun 09, 2020
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Michel Lespinasse authored
Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by:
Michel Lespinasse <walken@google.com> Signed-off-by:
Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by:
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Michel Lespinasse authored
Add new APIs to assert that mmap_sem is held. Using this instead of rwsem_is_locked and lockdep_assert_held[_write] makes the assertions more tolerant of future changes to the lock type. Signed-off-by:
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Michel Lespinasse authored
This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by:
Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by:
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- Jun 05, 2020
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Waiman Long authored
For kvmalloc'ed data object that contains sensitive information like cryptographic keys, we need to make sure that the buffer is always cleared before freeing it. Using memset() alone for buffer clearing may not provide certainty as the compiler may compile it away. To be sure, the special memzero_explicit() has to be used. This patch introduces a new kvfree_sensitive() for freeing those sensitive data objects allocated by kvmalloc(). The relevant places where kvfree_sensitive() can be used are modified to use it. Fixes: 4f088249 ("KEYS: Avoid false positive ENOMEM error on key read") Suggested-by:
Waiman Long <longman@redhat.com> Signed-off-by:
Eric Biggers <ebiggers@google.com> Acked-by:
David Howells <dhowells@redhat.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Uladzislau Rezki <urezki@gmail.com> Link: http://lkml.kernel.org/r/20200407200318.11711-1-longman@redhat.com Signed-off-by:
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Feng Tang authored
This check was added by commit 82f71ae4 ("mm: catch memory commitment underflow") in 2014 to have a safety check for issues which have been fixed. And there has been few report caught by it, as described in its commit log: : This shouldn't happen any more - the previous two patches fixed : the committed_as underflow issues. But it was really found by Qian Cai when he used the LTP memory stress suite to test a RFC patchset, which tries to improve scalability of per-cpu counter 'vm_committed_as', by chosing a bigger 'batch' number for loose overcommit policies (OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS), while keeping current number for OVERCOMMIT_NEVER. With that patchset, when system firstly uses a loose policy, the 'vm_committed_as' count could be a big negative value, as its big 'batch' number allows a big deviation, then when the policy is changed to OVERCOMMIT_NEVER, the 'batch' will be decreased to a much smaller value, thus hits this WARN check. To mitigate this, one proposed solution is to queue work on all online CPUs to do a local sync for 'vm_committed_as' when changing policy to OVERCOMMIT_NEVER, plus some global syncing to garante the case won't be hit. But this solution is costy and slow, given this check hasn't shown real trouble or benefit, simply drop it from one hot path of MM. And perf stats does show some tiny saving for removing it. Reported-by:
Qian Cai <cai@lca.pw> Signed-off-by:
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- Jun 02, 2020
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Christoph Hellwig authored
Just use __vmalloc_node instead which gets and extra argument. To be able to to use __vmalloc_node in all caller make it available outside of vmalloc and implement it in nommu.c. [akpm@linux-foundation.org: fix nommu build] Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: Gao Xiang <xiang@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Kelley <mikelley@microsoft.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20200414131348.444715-25-hch@lst.de Signed-off-by:
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- Apr 27, 2020
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Christoph Hellwig authored
Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by:
Andrey Ignatov <rdna@fb.com> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- Dec 01, 2019
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Wei Yang authored
Now we use rb_parent to get next, while this is not necessary. When prev is NULL, this means vma should be the first element in the list. Then next should be current first one (mm->mmap), no matter whether we have parent or not. After removing it, the code shows the beauty of symmetry. Link: http://lkml.kernel.org/r/20190813032656.16625-1-richardw.yang@linux.intel.com Signed-off-by:
Wei Yang <richardw.yang@linux.intel.com> Acked-by:
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Wei Yang authored
Just make the code a little easier to read. Link: http://lkml.kernel.org/r/20191006012636.31521-3-richardw.yang@linux.intel.com Signed-off-by:
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- Sep 24, 2019
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Alexandre Ghiti authored
This commits selects ARCH_HAS_ELF_RANDOMIZE when an arch uses the generic topdown mmap layout functions so that this security feature is on by default. Note that this commit also removes the possibility for arm64 to have elf randomization and no MMU: without MMU, the security added by randomization is worth nothing. Link: http://lkml.kernel.org/r/20190730055113.23635-6-alex@ghiti.fr Signed-off-by:
Alexandre Ghiti <alex@ghiti.fr> Acked-by:
Kees Cook <keescook@chromium.org> Reviewed-by:
Luis Chamberlain <mcgrof@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: James Hogan <jhogan@kernel.org> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Alexandre Ghiti authored
arm64 handles top-down mmap layout in a way that can be easily reused by other architectures, so make it available in mm. It then introduces a new config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT that can be set by other architectures to benefit from those functions. Note that this new config depends on MMU being enabled, if selected without MMU support, a warning will be thrown. Link: http://lkml.kernel.org/r/20190730055113.23635-5-alex@ghiti.fr Signed-off-by:
Christoph Hellwig <hch@infradead.org> Acked-by:
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Alexandre Ghiti authored
Patch series "Provide generic top-down mmap layout functions", v6. This series introduces generic functions to make top-down mmap layout easily accessible to architectures, in particular riscv which was the initial goal of this series. The generic implementation was taken from arm64 and used successively by arm, mips and finally riscv. Note that in addition the series fixes 2 issues: - stack randomization was taken into account even if not necessary. - [1] fixed an issue with mmap base which did not take into account randomization but did not report it to arm and mips, so by moving arm64 into a generic library, this problem is now fixed for both architectures. This work is an effort to factorize architecture functions to avoid code duplication and oversights as in [1]. [1]: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html This patch (of 14): This preparatory commit moves this function so that further introduction of generic topdown mmap layout is contained only in mm/util.c. Link: http://lkml.kernel.org/r/20190730055113.23635-2-alex@ghiti.fr Signed-off-by:
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Song Liu authored
Patch series "THP aware uprobe", v13. This patchset makes uprobe aware of THPs. Currently, when uprobe is attached to text on THP, the page is split by FOLL_SPLIT. As a result, uprobe eliminates the performance benefit of THP. This set makes uprobe THP-aware. Instead of FOLL_SPLIT, we introduces FOLL_SPLIT_PMD, which only split PMD for uprobe. After all uprobes within the THP are removed, the PTE-mapped pages are regrouped as huge PMD. This set (plus a few THP patches) is also available at https://github.com/liu-song-6/linux/tree/uprobe-thp This patch (of 6): Move memcmp_pages() to mm/util.c and pages_identical() to mm.h, so that we can use them in other files. Link: http://lkml.kernel.org/r/20190815164525.1848545-2-songliubraving@fb.com Signed-off-by:
Song Liu <songliubraving@fb.com> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by:
Oleg Nesterov <oleg@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <matthew.wilcox@oracle.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by:
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Matthew Wilcox (Oracle) authored
Replace 1 << compound_order(page) with compound_nr(page). Minor improvements in readability. Link: http://lkml.kernel.org/r/20190721104612.19120-4-willy@infradead.org Signed-off-by:
Ira Weiny <ira.weiny@intel.com> Acked-by:
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- Jul 17, 2019
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Daniel Jordan authored
locked_vm accounting is done roughly the same way in five places, so unify them in a helper. Include the helper's caller in the debug print to distinguish between callsites. Error codes stay the same, so user-visible behavior does too. The one exception is that the -EPERM case in tce_account_locked_vm is removed because Alexey has never seen it triggered. [daniel.m.jordan@oracle.com: v3] Link: http://lkml.kernel.org/r/20190529205019.20927-1-daniel.m.jordan@oracle.com [sfr@canb.auug.org.au: fix mm/util.c] Link: http://lkml.kernel.org/r/20190524175045.26897-1-daniel.m.jordan@oracle.com Signed-off-by:
Stephen Rothwell <sfr@canb.auug.org.au> Tested-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Acked-by:
Alex Williamson <alex.williamson@redhat.com> Cc: Alan Tull <atull@kernel.org> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Christoph Lameter <cl@linux.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Moritz Fischer <mdf@kernel.org> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Steve Sistare <steven.sistare@oracle.com> Cc: Wu Hao <hao.wu@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Signed-off-by:
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- Jul 12, 2019
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Christoph Hellwig authored
Always build mm/gup.c so that we don't have to provide separate nommu stubs. Also merge the get_user_pages_fast and __get_user_pages_fast stubs when HAVE_FAST_GUP into the main implementations, which will never call the fast path if HAVE_FAST_GUP is not set. This also ensures the new put_user_pages* helpers are available for nommu, as those are currently missing, which would create a problem as soon as we actually grew users for it. Link: http://lkml.kernel.org/r/20190625143715.1689-13-hch@lst.de Signed-off-by:
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- Jun 01, 2019
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Michal Koutný authored
The commit a3b609ef ("proc read mm's {arg,env}_{start,end} with mmap semaphore taken.") added synchronization of reading argument/environment boundaries under mmap_sem. Later commit 88aa7cc6 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") avoided the coarse use of mmap_sem in similar situations. But there still remained two places that (mis)use mmap_sem. get_cmdline should also use arg_lock instead of mmap_sem when it reads the boundaries. The second place that should use arg_lock is in prctl_set_mm. By protecting the boundaries fields with the arg_lock, we can downgrade mmap_sem to reader lock (analogous to what we already do in prctl_set_mm_map). [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20190502125203.24014-3-mkoutny@suse.com Fixes: 88aa7cc6 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") Signed-off-by:
Michal Koutný <mkoutny@suse.com> Signed-off-by:
Cyrill Gorcunov <gorcunov@gmail.com> Acked-by:
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- May 21, 2019
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Thomas Gleixner authored
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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- May 14, 2019
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Johannes Weiner authored
With the default overcommit==guess we occasionally run into mmap rejections despite plenty of memory that would get dropped under pressure but just isn't accounted reclaimable. One example of this is dying cgroups pinned by some page cache. A previous case was auxiliary path name memory associated with dentries; we have since annotated those allocations to avoid overcommit failures (see d79f7aa4 ("mm: treat indirectly reclaimable memory as free in overcommit logic")). But trying to classify all allocated memory reliably as reclaimable and unreclaimable is a bit of a fool's errand. There could be a myriad of dependencies that constantly change with kernel versions. It becomes even more questionable of an effort when considering how this estimate of available memory is used: it's not compared to the system-wide allocated virtual memory in any way. It's not even compared to the allocating process's address space. It's compared to the single allocation request at hand! So we have an elaborate left-hand side of the equation that tries to assess the exact breathing room the system has available down to a page - and then compare it to an isolated allocation request with no additional context. We could fail an allocation of N bytes, but for two allocations of N/2 bytes we'd do this elaborate dance twice in a row and then still let N bytes of virtual memory through. This doesn't make a whole lot of sense. Let's take a step back and look at the actual goal of the heuristic. From the documentation: Heuristic overcommit handling. Obvious overcommits of address space are refused. Used for a typical system. It ensures a seriously wild allocation fails while allowing overcommit to reduce swap usage. root is allowed to allocate slightly more memory in this mode. This is the default. If all we want to do is catch clearly bogus allocation requests irrespective of the general virtual memory situation, the physical memory counter-part doesn't need to be that complicated, either. When in GUESS mode, catch wild allocations by comparing their request size to total amount of ram and swap in the system. Link: http://lkml.kernel.org/r/20190412191418.26333-1-hannes@cmpxchg.org Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Acked-by:
Roman Gushchin <guro@fb.com> Signed-off-by:
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Ira Weiny authored
To facilitate additional options to get_user_pages_fast() change the singular write parameter to be gup_flags. This patch does not change any functionality. New functionality will follow in subsequent patches. Some of the get_user_pages_fast() call sites were unchanged because they already passed FOLL_WRITE or 0 for the write parameter. NOTE: It was suggested to change the ordering of the get_user_pages_fast() arguments to ensure that callers were converted. This breaks the current GUP call site convention of having the returned pages be the final parameter. So the suggestion was rejected. Link: http://lkml.kernel.org/r/20190328084422.29911-4-ira.weiny@intel.com Link: http://lkml.kernel.org/r/20190317183438.2057-4-ira.weiny@intel.com Signed-off-by:
Mike Marshall <hubcap@omnibond.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Hogan <jhogan@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by:
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- Apr 06, 2019
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Andrew Morton authored
The kerneldoc misdescribes strndup_user()'s return value. Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Timur Tabi <timur@freescale.com> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Kumar Gala <galak@kernel.crashing.org> Signed-off-by:
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