- 12 Jul, 2019 40 commits
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Shakeel Butt authored
Commit d46eb14b ("fs: fsnotify: account fsnotify metadata to kmemcg") added remote memcg charging for fanotify and inotify event objects. The aim was to charge the memory to the listener who is interested in the events but without triggering the OOM killer. Otherwise there would be security concerns for the listener. At the time, oom-kill trigger was not in the charging path. A parallel work added the oom-kill back to charging path i.e. commit 29ef680a ("memcg, oom: move out_of_memory back to the charge path"). So to not trigger oom-killer in the remote memcg, explicitly add __GFP_RETRY_MAYFAIL to the fanotigy and inotify event allocations. Link: http://lkml.kernel.org/r/20190514212259.156585-2-shakeelb@google.comSigned-off-by:
Shakeel Butt <shakeelb@google.com> Reviewed-by:
Roman Gushchin <guro@fb.com> Acked-by:
Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Shakeel Butt authored
The documentation of __GFP_RETRY_MAYFAIL clearly mentioned that the OOM killer will not be triggered and indeed the page alloc does not invoke OOM killer for such allocations. However we do trigger memcg OOM killer for __GFP_RETRY_MAYFAIL. Fix that. This flag will used later to not trigger oom-killer in the charging path for fanotify and inotify event allocations. Link: http://lkml.kernel.org/r/20190514212259.156585-1-shakeelb@google.comSigned-off-by:
Michal Hocko <mhocko@suse.com> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by:
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Huang Ying authored
Via commit 4b3ef9da ("mm/swap: split swap cache into 64MB trunks"), after swapoff, the address_space associated with the swap device will be freed. So swap_address_space() users which touch the address_space need some kind of mechanism to prevent the address_space from being freed during accessing. When mincore processes an unmapped range for swapped shmem pages, it doesn't hold the lock to prevent swap device from being swapped off. So the following race is possible: CPU1 CPU2 do_mincore() swapoff() walk_page_range() mincore_unmapped_range() __mincore_unmapped_range mincore_page as = swap_address_space() ... exit_swap_address_space() ... kvfree(spaces) find_get_page(as) The address space may be accessed after being freed. To fix the race, get_swap_device()/put_swap_device() is used to enclose find_get_page() to check whether the swap entry is valid and prevent the swap device from being swapoff during accessing. Link: http://lkml.kernel.org/r/20190611020510.28251-1-ying.huang@intel.com Fixes: 4b3ef9da ("mm/swap: split swap cache into 64MB trunks") Signed-off-by:
"Huang, Ying" <ying.huang@intel.com> Reviewed-by:
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Aaron Lu authored
swap_extent is used to map swap page offset to backing device's block offset. For a continuous block range, one swap_extent is used and all these swap_extents are managed in a linked list. These swap_extents are used by map_swap_entry() during swap's read and write path. To find out the backing device's block offset for a page offset, the swap_extent list will be traversed linearly, with curr_swap_extent being used as a cache to speed up the search. This works well as long as swap_extents are not huge or when the number of processes that access swap device are few, but when the swap device has many extents and there are a number of processes accessing the swap device concurrently, it can be a problem. On one of our servers, the disk's remaining size is tight: $df -h Filesystem Size Used Avail Use% Mounted on ... ... /dev/nvme0n1p1 1.8T 1.3T 504G 72% /home/t4 When creating a 80G swapfile there, there are as many as 84656 swap extents. The end result is, kernel spends abou 30% time in map_swap_entry() and swap throughput is only 70MB/s. As a comparison, when I used smaller sized swapfile, like 4G whose swap_extent dropped to 2000, swap throughput is back to 400-500MB/s and map_swap_entry() is about 3%. One downside of using rbtree for swap_extent is, 'struct rbtree' takes 24 bytes while 'struct list_head' takes 16 bytes, that's 8 bytes more for each swap_extent. For a swapfile that has 80k swap_extents, that means 625KiB more memory consumed. Test: Since it's not possible to reboot that server, I can not test this patch diretly there. Instead, I tested it on another server with NVMe disk. I created a 20G swapfile on an NVMe backed XFS fs. By default, the filesystem is quite clean and the created swapfile has only 2 extents. Testing vanilla and this patch shows no obvious performance difference when swapfile is not fragmented. To see the patch's effects, I used some tweaks to manually fragment the swapfile by breaking the extent at 1M boundary. This made the swapfile have 20K extents. nr_task=4 kernel swapout(KB/s) map_swap_entry(perf) swapin(KB/s) map_swap_entry(perf) vanilla 165191 90.77% 171798 90.21% patched 858993 +420% 2.16% 715827 +317% 0.77% nr_task=8 kernel swapout(KB/s) map_swap_entry(perf) swapin(KB/s) map_swap_entry(perf) vanilla 306783 92.19% 318145 87.76% patched 954437 +211% 2.35% 1073741 +237% 1.57% swapout: the throughput of swap out, in KB/s, higher is better 1st map_swap_entry: cpu cycles percent sampled by perf swapin: the throughput of swap in, in KB/s, higher is better. 2nd map_swap_entry: cpu cycles percent sampled by perf nr_task=1 doesn't show any difference, this is due to the curr_swap_extent can be effectively used to cache the correct swap extent for single task workload. [akpm@linux-foundation.org: s/BUG_ON(1)/BUG()/] Link: http://lkml.kernel.org/r/20190523142404.GA181@aaronluSigned-off-by:
Aaron Lu <ziqian.lzq@antfin.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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Huang Ying authored
total_swapcache_pages() may race with swapper_spaces[] allocation and freeing. Previously, this is protected with a swapper_spaces[] specific RCU mechanism. To simplify the logic/code complexity, it is replaced with get/put_swap_device(). The code line number is reduced too. Although not so important, the swapoff() performance improves too because one synchronize_rcu() call during swapoff() is deleted. [ying.huang@intel.com: fix bad swap file entry warning] Link: http://lkml.kernel.org/r/20190531024102.21723-1-ying.huang@intel.com Link: http://lkml.kernel.org/r/20190527082714.12151-1-ying.huang@intel.comSigned-off-by:
Mike Kravetz <mike.kravetz@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by:
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Huang Ying authored
When swapin is performed, after getting the swap entry information from the page table, system will swap in the swap entry, without any lock held to prevent the swap device from being swapoff. This may cause the race like below, CPU 1 CPU 2 ----- ----- do_swap_page swapin_readahead __read_swap_cache_async swapoff swapcache_prepare p->swap_map = NULL __swap_duplicate p->swap_map[?] /* !!! NULL pointer access */ Because swapoff is usually done when system shutdown only, the race may not hit many people in practice. But it is still a race need to be fixed. To fix the race, get_swap_device() is added to check whether the specified swap entry is valid in its swap device. If so, it will keep the swap entry valid via preventing the swap device from being swapoff, until put_swap_device() is called. Because swapoff() is very rare code path, to make the normal path runs as fast as possible, rcu_read_lock/unlock() and synchronize_rcu() instead of reference count is used to implement get/put_swap_device(). >From get_swap_device() to put_swap_device(), RCU reader side is locked, so synchronize_rcu() in swapoff() will wait until put_swap_device() is called. In addition to swap_map, cluster_info, etc. data structure in the struct swap_info_struct, the swap cache radix tree will be freed after swapoff, so this patch fixes the race between swap cache looking up and swapoff too. Races between some other swap cache usages and swapoff are fixed too via calling synchronize_rcu() between clearing PageSwapCache() and freeing swap cache data structure. Another possible method to fix this is to use preempt_off() + stop_machine() to prevent the swap device from being swapoff when its data structure is being accessed. The overhead in hot-path of both methods is similar. The advantages of RCU based method are, 1. stop_machine() may disturb the normal execution code path on other CPUs. 2. File cache uses RCU to protect its radix tree. If the similar mechanism is used for swap cache too, it is easier to share code between them. 3. RCU is used to protect swap cache in total_swapcache_pages() and exit_swap_address_space() already. The two mechanisms can be merged to simplify the logic. Link: http://lkml.kernel.org/r/20190522015423.14418-1-ying.huang@intel.com Fixes: 235b6217 ("mm/swap: add cluster lock") Signed-off-by:
Andrea Parri <andrea.parri@amarulasolutions.com> Not-nacked-by:
Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: David Rientjes <rientjes@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Jiang <dave.jiang@intel.com> Signed-off-by:
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Yang Shi authored
Commit 6b4c9f44 ("filemap: drop the mmap_sem for all blocking operations") changed when mmap_sem is dropped during filemap page fault and when returning VM_FAULT_RETRY. Correct the comment to reflect the change. Link: http://lkml.kernel.org/r/1556234531-108228-1-git-send-email-yang.shi@linux.alibaba.comSigned-off-by:
Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Acked-by:
Song Liu <songliubraving@fb.com> Signed-off-by:
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Christoph Hellwig authored
Fix the callback 9p passes to read_cache_page to actually have the proper type expected. Casting around function pointers can easily hide typing bugs, and defeats control flow protection. Link: http://lkml.kernel.org/r/20190520055731.24538-5-hch@lst.deSigned-off-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
Kees Cook <keescook@chromium.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by:
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Christoph Hellwig authored
Fix the callback jffs2 passes to read_cache_page to actually have the proper type expected. Casting around function pointers can easily hide typing bugs, and defeats control flow protection. Link: http://lkml.kernel.org/r/20190520055731.24538-4-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
We can just pass a NULL filler and do the right thing inside of do_read_cache_page based on the NULL parameter. Link: http://lkml.kernel.org/r/20190520055731.24538-3-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Patch series "fix filler_t callback type mismatches", v2. Casting mapping->a_ops->readpage to filler_t causes an indirect call type mismatch with Control-Flow Integrity checking. This change fixes the mismatch in read_cache_page_gfp and read_mapping_page by adding using a NULL filler argument as an indication to call ->readpage directly, and by passing the right parameter callbacks in nfs and jffs2. This patch (of 4): Code cleanup. Link: http://lkml.kernel.org/r/20190520055731.24538-2-hch@lst.deSigned-off-by:
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Vlastimil Babka authored
When debug_pagealloc is enabled, we currently allocate the page_ext array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that we have the page_type field in struct page, we can use that instead, as guard pages are neither PageSlab nor mapped to userspace. This reduces memory overhead when debug_pagealloc is enabled and there are no other features requiring the page_ext array. Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.czSigned-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by:
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Vlastimil Babka authored
The page allocator checks struct pages for expected state (mapcount, flags etc) as pages are being allocated (check_new_page()) and freed (free_pages_check()) to provide some defense against errors in page allocator users. Prior commits 479f854a ("mm, page_alloc: defer debugging checks of pages allocated from the PCP") and 4db7548c ("mm, page_alloc: defer debugging checks of freed pages until a PCP drain") this has happened for order-0 pages as they were allocated from or freed to the per-cpu caches (pcplists). Since those are fast paths, the checks are now performed only when pages are moved between pcplists and global free lists. This however lowers the chances of catching errors soon enough. In order to increase the chances of the checks to catch errors, the kernel has to be rebuilt with CONFIG_DEBUG_VM, which also enables multiple other internal debug checks (VM_BUG_ON() etc), which is suboptimal when the goal is to catch errors in mm users, not in mm code itself. To catch some wrong users of the page allocator we have CONFIG_DEBUG_PAGEALLOC, which is designed to have virtually no overhead unless enabled at boot time. Memory corruptions when writing to freed pages have often the same underlying errors (use-after-free, double free) as corrupting the corresponding struct pages, so this existing debugging functionality is a good fit to extend by also perform struct page checks at least as often as if CONFIG_DEBUG_VM was enabled. Specifically, after this patch, when debug_pagealloc is enabled on boot, and CONFIG_DEBUG_VM disabled, pages are checked when allocated from or freed to the pcplists *in addition* to being moved between pcplists and free lists. When both debug_pagealloc and CONFIG_DEBUG_VM are enabled, pages are checked when being moved between pcplists and free lists *in addition* to when allocated from or freed to the pcplists. When debug_pagealloc is not enabled on boot, the overhead in fast paths should be virtually none thanks to the use of static key. Link: http://lkml.kernel.org/r/20190603143451.27353-3-vbabka@suse.czSigned-off-by:
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Vlastimil Babka authored
Patch series "debug_pagealloc improvements". I have been recently debugging some pcplist corruptions, where it would be useful to perform struct page checks immediately as pages are allocated from and freed to pcplists, which is now only possible by rebuilding the kernel with CONFIG_DEBUG_VM (details in Patch 2 changelog). To make this kind of debugging simpler in future on a distro kernel, I have improved CONFIG_DEBUG_PAGEALLOC so that it has even smaller overhead when not enabled at boot time (Patch 1) and also when enabled (Patch 3), and extended it to perform the struct page checks more often when enabled (Patch 2). Now it can be configured in when building a distro kernel without extra overhead, and debugging page use after free or double free can be enabled simply by rebooting with debug_pagealloc=on. This patch (of 3): CONFIG_DEBUG_PAGEALLOC has been redesigned by 031bc574 ("mm/debug-pagealloc: make debug-pagealloc boottime configurable") to allow being always enabled in a distro kernel, but only perform its expensive functionality when booted with debug_pagelloc=on. We can further reduce the overhead when not boot-enabled (including page allocator fast paths) using static keys. This patch introduces one for debug_pagealloc core functionality, and another for the optional guard page functionality (enabled by booting with debug_guardpage_minorder=X). Link: http://lkml.kernel.org/r/20190603143451.27353-2-vbabka@suse.czSigned-off-by:
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Nicolas Boichat authored
When failslab was originally written, the intention of the "ignore-gfp-wait" flag default value ("N") was to fail GFP_ATOMIC allocations. Those were defined as (__GFP_HIGH), and the code would test for __GFP_WAIT (0x10u). However, since then, __GFP_WAIT was replaced by __GFP_RECLAIM (___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM), and GFP_ATOMIC is now defined as (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM). This means that when the flag is false, almost no allocation ever fails (as even GFP_ATOMIC allocations contain ___GFP_KSWAPD_RECLAIM). Restore the original intent of the code, by ignoring calls that directly reclaim only (__GFP_DIRECT_RECLAIM), and thus, failing GFP_ATOMIC calls again by default. Link: http://lkml.kernel.org/r/20190520214514.81360-1-drinkcat@chromium.org Fixes: 71baba4b ("mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM") Signed-off-by:Nicolas Boichat <drinkcat@chromium.org> Reviewed-by:
Akinobu Mita <akinobu.mita@gmail.com> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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Andrew Morton authored
Cc: Henry Burns <henryburns@google.com> Cc: Jonathan Adams <jwadams@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Xidong Wang <wangxidong_97@163.com> Signed-off-by:
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Denis Efremov authored
Previously totalram_pages was the global variable. Currently, totalram_pages is the static inline function from the include/linux/mm.h However, the function is also marked as EXPORT_SYMBOL, which is at best an odd combination. Because there is no point for the static inline function from a public header to be exported, this commit removes the EXPORT_SYMBOL() marking. It will be still possible to use the function in modules because all the symbols it depends on are exported. Link: http://lkml.kernel.org/r/20190710141031.15642-1-efremov@linux.com Fixes: ca79b0c2 ("mm: convert totalram_pages and totalhigh_pages variables to atomic") Signed-off-by:
Denis Efremov <efremov@linux.com> Acked-by:
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Sebastian Andrzej Siewior authored
For spinlocks the type spinlock_t should be used instead of "struct spinlock". Use spinlock_t for spinlock's definition. Link: http://lkml.kernel.org/r/20190704153803.12739-3-bigeasy@linutronix.deSigned-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by:
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Pingfan Liu authored
undo_isolate_page_range() never fails, so no need to return value. Link: http://lkml.kernel.org/r/1562075604-8979-1-git-send-email-kernelfans@gmail.comSigned-off-by:
Pingfan Liu <kernelfans@gmail.com> Acked-by:
Oscar Salvador <osalvador@suse.de> Reviewed-by:
Anshuman Khandual <anshuman.khandual@arm.com> Cc: Qian Cai <cai@lca.pw> Signed-off-by:
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Christoph Hellwig authored
account_page_dirtied() is only used by our set_page_dirty() helpers and should not be used anywhere else. Link: http://lkml.kernel.org/r/20190605183702.30572-1-hch@lst.deSigned-off-by:
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Alexey Dobriyan authored
The field is only used in swap code. Link: http://lkml.kernel.org/r/20190503190500.GA30589@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Acked-by:
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Jason Gunthorpe authored
Instead of using defines, which loses type safety and provokes unused variable warnings from gcc, put the constants into static inlines. Link: http://lkml.kernel.org/r/20190522235102.GA15370@mellanox.comSigned-off-by:
Jason Gunthorpe <jgg@mellanox.com> Suggested-by:
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Miklos Szeredi authored
Make the success case use the same cleanup path as the failure case. Link: http://lkml.kernel.org/r/20190523134024.GC24093@localhost.localdomainSigned-off-by:
Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:
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Bharath Vedartham authored
follow_page_mask() is only used in gup.c, make it static. Link: http://lkml.kernel.org/r/20190510190831.GA4061@bharath12345-Inspiron-5559Signed-off-by:
Bharath Vedartham <linux.bhar@gmail.com> Reviewed-by:
Ira Weiny <ira.weiny@intel.com> Signed-off-by:
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Mike Rapoport authored
The ARCH_SELECT_MEMORY_MODEL option is enabled only for 64-bit. However, 64-bit configuration also enables ARCH_SPARSEMEM_DEFAULT and there is no ARCH_FLATMEM_ENABLE in arch/sparc/Kconfig. With such settings, the dependencies in mm/Kconfig are always evaluated to SPARSEMEM=y for 64-bit and to FLATMEM=y for 32-bit. The ARCH_SELECT_MEMORY_MODEL option in arch/sparc/Kconfig does not affect anything and can be removed. Link: http://lkml.kernel.org/r/1556740577-4140-4-git-send-email-rppt@linux.ibm.comSigned-off-by:
Mike Rapoport <rppt@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Russell King <linux@armlinux.org.uk> Signed-off-by:
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Mike Rapoport authored
The only reason s390 has ARCH_SELECT_MEMORY_MODEL option in arch/s390/Kconfig is an ancient compile error with allnoconfig which was fixed by commit 97195d6b ("[S390] fix sparsemem related compile error with allnoconfig on s390") by adding the ARCH_SELECT_MEMORY_MODEL option. Since then a lot have changed and now allnoconfig builds just fine without ARCH_SELECT_MEMORY_MODEL, so it can be removed. Link: http://lkml.kernel.org/r/1556740577-4140-3-git-send-email-rppt@linux.ibm.comSigned-off-by:
Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Russell King <linux@armlinux.org.uk> Signed-off-by:
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Mike Rapoport authored
Patch series "remove ARCH_SELECT_MEMORY_MODEL where it has no effect". For several architectures the ARCH_SELECT_MEMORY_MODEL has no real effect because the dependencies for the memory model are always evaluated to a single value. Remove the ARCH_SELECT_MEMORY_MODEL from the Kconfigs for these architectures. This patch (of 3): The ARCH_SELECT_MEMORY_MODEL in arch/arm/Kconfig is enabled only when ARCH_SPARSEMEM_ENABLE=y. But in this case, ARCH_SPARSEMEM_DEFAULT is also enabled and this in turn enables SPARSEMEM_MANUAL. Since there is no definition of ARCH_FLATMEM_ENABLE in arch/arm/Kconfig, SPARSEMEM_MANUAL is the only enabled memory model, hence the final selection will evaluate to SPARSEMEM=y. Since ARCH_SPARSEMEM_ENABLE is set to 'y' only by several sub-arch configurations, the default for must sub-arches would be the falback to FLATMEM regardless of ARCH_SELECT_MEMORY_MODEL. Link: http://lkml.kernel.org/r/1556740577-4140-2-git-send-email-rppt@linux.ibm.comSigned-off-by:
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Andrew Morton authored
It has no callers and there is no virt_to_pfn_t(). Reported-by:
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Marco Elver authored
ksize() has been unconditionally unpoisoning the whole shadow memory region associated with an allocation. This can lead to various undetected bugs, for example, double-kzfree(). Specifically, kzfree() uses ksize() to determine the actual allocation size, and subsequently zeroes the memory. Since ksize() used to just unpoison the whole shadow memory region, no invalid free was detected. This patch addresses this as follows: 1. Add a check in ksize(), and only then unpoison the memory region. 2. Preserve kasan_unpoison_slab() semantics by explicitly unpoisoning the shadow memory region using the size obtained from __ksize(). Tested: 1. With SLAB allocator: a) normal boot without warnings; b) verified the added double-kzfree() is detected. 2. With SLUB allocator: a) normal boot without warnings; b) verified the added double-kzfree() is detected. [elver@google.com: s/BUG_ON/WARN_ON_ONCE/, per Kees] Link: http://lkml.kernel.org/r/20190627094445.216365-6-elver@google.com Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199359 Link: http://lkml.kernel.org/r/20190626142014.141844-6-elver@google.comSigned-off-by:
Marco Elver <elver@google.com> Acked-by:
Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> 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: Mark Rutland <mark.rutland@arm.com> Signed-off-by:
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Marco Elver authored
This refactors common code of ksize() between the various allocators into slab_common.c: __ksize() is the allocator-specific implementation without instrumentation, whereas ksize() includes the required KASAN logic. Link: http://lkml.kernel.org/r/20190626142014.141844-5-elver@google.comSigned-off-by:
Christoph Lameter <cl@linux.com> Reviewed-by:
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Marco Elver authored
Add a simple test that checks if double-kzfree is being detected correctly. Link: http://lkml.kernel.org/r/20190626142014.141844-4-elver@google.comSigned-off-by:
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Marco Elver authored
This changes {,__}kasan_check_{read,write} functions to return a boolean denoting if the access was valid or not. [sfr@canb.auug.org.au: include types.h for "bool"] Link: http://lkml.kernel.org/r/20190705184949.13cdd021@canb.auug.org.au Link: http://lkml.kernel.org/r/20190626142014.141844-3-elver@google.comSigned-off-by:Stephen Rothwell <sfr@canb.auug.org.au> Reviewed-by:
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Marco Elver authored
Patch series "mm/kasan: Add object validation in ksize()", v3. This patch (of 5): This introduces __kasan_check_{read,write}. __kasan_check functions may be used from anywhere, even compilation units that disable instrumentation selectively. This change eliminates the need for the __KASAN_INTERNAL definition. [elver@google.com: v5] Link: http://lkml.kernel.org/r/20190708170706.174189-2-elver@google.com Link: http://lkml.kernel.org/r/20190626142014.141844-2-elver@google.comSigned-off-by:Mark Rutland <mark.rutland@arm.com> Reviewed-by:
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Marco Elver authored
This adds a new header to asm-generic to allow optionally instrumenting architecture-specific asm implementations of bitops. This change includes the required change for x86 as reference and changes the kernel API doc to point to bitops-instrumented.h instead. Rationale: the functions in x86's bitops.h are no longer the kernel API functions, but instead the arch_ prefixed functions, which are then instrumented via bitops-instrumented.h. Other architectures can similarly add support for asm implementations of bitops. The documentation text was derived from x86 and existing bitops asm-generic versions: 1) references to x86 have been removed; 2) as a result, some of the text had to be reworded for clarity and consistency. Tested using lib/test_kasan with bitops tests (pre-requisite patch). Bugzilla ref: https://bugzilla.kernel.org/show_bug.cgi?id=198439 Link: http://lkml.kernel.org/r/20190613125950.197667-4-elver@google.comSigned-off-by:
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Marco Elver authored
This patch is a pre-requisite for enabling KASAN bitops instrumentation; using static_cpu_has instead of boot_cpu_has avoids instrumentation of test_bit inside the uaccess region. With instrumentation, the KASAN check would otherwise be flagged by objtool. For consistency, kernel/signal.c was changed to mirror this change, however, is never instrumented with KASAN (currently unsupported under x86 32bit). Link: http://lkml.kernel.org/r/20190613125950.197667-3-elver@google.comSigned-off-by:
H. Peter Anvin <hpa@zytor.com> Acked-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
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Marco Elver authored
Patch series "Bitops instrumentation for KASAN", v5. This patch (of 3): This adds bitops tests to the test_kasan module. In a follow-up patch, support for bitops instrumentation will be added. Link: http://lkml.kernel.org/r/20190613125950.197667-2-elver@google.comSigned-off-by:
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Marco Elver authored
This adds support for printing stack frame description on invalid stack accesses. The frame description is embedded by the compiler, which is parsed and then pretty-printed. Currently, we can only print the stack frame info for accesses to the task's own stack, but not accesses to other tasks' stacks. Example of what it looks like: page dumped because: kasan: bad access detected addr ffff8880673ef98a is located in stack of task insmod/2008 at offset 106 in frame: kasan_stack_oob+0x0/0xf5 [test_kasan] this frame has 2 objects: [32, 36) 'i' [96, 106) 'stack_array' Memory state around the buggy address: Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198435 Link: http://lkml.kernel.org/r/20190522100048.146841-1-elver@google.comSigned-off-by:
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André Almeida authored
Wikipedia now has a main article to "tracing garbage collector" topic. Change the URL and use the reStructuredText syntax for hyperlinks and add more details about the use of the tool. Add a section about how to use the kmemleak-test module to test the memory leak scanning. Link: http://lkml.kernel.org/r/20190612155231.19448-2-andrealmeid@collabora.comSigned-off-by:
André Almeida <andrealmeid@collabora.com> Acked-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by:
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André Almeida authored
According to POSIX, EBUSY means that the "device or resource is busy", and this can lead to people thinking that the file `/sys/kernel/debug/kmemleak/` is somehow locked or being used by other process. Change this error code to a more appropriate one. Link: http://lkml.kernel.org/r/20190612155231.19448-1-andrealmeid@collabora.comSigned-off-by:
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Dmitry Vyukov authored
in_softirq() is a wrong predicate to check if we are in a softirq context. It also returns true if we have BH disabled, so objects are falsely stamped with "softirq" comm. The correct predicate is in_serving_softirq(). If user does cat from /sys/kernel/debug/kmemleak previously they would see this, which is clearly wrong, this is system call context (see the comm): unreferenced object 0xffff88805bd661c0 (size 64): comm "softirq", pid 0, jiffies 4294942959 (age 12.400s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 ff ff ff ff 00 00 00 00 ................ 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ backtrace: [<0000000007dcb30c>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline] [<0000000007dcb30c>] slab_post_alloc_hook mm/slab.h:439 [inline] [<0000000007dcb30c>] slab_alloc mm/slab.c:3326 [inline] [<0000000007dcb30c>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553 [<00000000969722b7>] kmalloc include/linux/slab.h:547 [inline] [<00000000969722b7>] kzalloc include/linux/slab.h:742 [inline] [<00000000969722b7>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline] [<00000000969722b7>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085 [<00000000a4134b5f>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475 [<00000000d20248ad>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957 [<000000003d367be7>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246 [<000000003c7c76af>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616 [<000000000c1aeb23>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130 [<000000000157b92b>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078 [<00000000a9f3d058>] __do_sys_setsockopt net/socket.c:2089 [inline] [<00000000a9f3d058>] __se_sys_setsockopt net/socket.c:2086 [inline] [<00000000a9f3d058>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086 [<000000001b8da885>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301 [<00000000ba770c62>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 now they will see this: unreferenced object 0xffff88805413c800 (size 64): comm "syz-executor.4", pid 8960, jiffies 4294994003 (age 14.350s) hex dump (first 32 bytes): 00 7a 8a 57 80 88 ff ff e0 00 00 01 00 00 00 00 .z.W............ 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ backtrace: [<00000000c5d3be64>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline] [<00000000c5d3be64>] slab_post_alloc_hook mm/slab.h:439 [inline] [<00000000c5d3be64>] slab_alloc mm/slab.c:3326 [inline] [<00000000c5d3be64>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553 [<0000000023865be2>] kmalloc include/linux/slab.h:547 [inline] [<0000000023865be2>] kzalloc include/linux/slab.h:742 [inline] [<0000000023865be2>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline] [<0000000023865be2>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085 [<000000003029a9d4>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475 [<00000000ccd0a87c>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957 [<00000000a85a3785>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246 [<00000000ec13c18d>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616 [<0000000052d748e3>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130 [<00000000512f1014>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078 [<00000000181758bc>] __do_sys_setsockopt net/socket.c:2089 [inline] [<00000000181758bc>] __se_sys_setsockopt net/socket.c:2086 [inline] [<00000000181758bc>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086 [<00000000d4b73623>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301 [<00000000c1098bec>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Link: http://lkml.kernel.org/r/20190517171507.96046-1-dvyukov@gmail.comSigned-off-by:Dmitry Vyukov <dvyukov@google.com> Acked-by:
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