starfive-tech/linux.git/mm/vmalloc.c, branch visionfive_v1_5.13

mm/vmalloc: unbreak kasan vmalloc support

2021-06-25T02:40:54+00:00

In commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings"), __vmalloc_node_range was changed such that __get_vm_area_node was no longer called with the requested/real size of the vmalloc allocation, but rather with a rounded-up size. This means that __get_vm_area_node called kasan_unpoision_vmalloc() with a rounded up size rather than the real size. This led to it allowing access to too much memory and so missing vmalloc OOBs and failing the kasan kunit tests. Pass the real size and the desired shift into __get_vm_area_node. This allows it to round up the size for the underlying allocators while still unpoisioning the correct quantity of shadow memory. Adjust the other call-sites to pass in PAGE_SHIFT for the shift value. Link: https://lkml.kernel.org/r/20210617081330.98629-1-dja@axtens.net Link: https://bugzilla.kernel.org/show_bug.cgi?id=213335 Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by: Daniel Axtens Tested-by: David Gow Reviewed-by: Nicholas Piggin Reviewed-by: Uladzislau Rezki (Sony) Tested-by: Andrey Konovalov Acked-by: Andrey Konovalov Cc: Dmitry Vyukov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc: add vmalloc_no_huge

2021-06-25T02:40:53+00:00

Patch series "mm: add vmalloc_no_huge and use it", v4. Add vmalloc_no_huge() and export it, so modules can allocate memory with small pages. Use the newly added vmalloc_no_huge() in KVM on s390 to get around a hardware limitation. This patch (of 2): Commit 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") added support for hugepage vmalloc mappings, it also added the flag VM_NO_HUGE_VMAP for __vmalloc_node_range to request the allocation to be performed with 0-order non-huge pages. This flag is not accessible when calling vmalloc, the only option is to call directly __vmalloc_node_range, which is not exported. This means that a module can't vmalloc memory with small pages. Case in point: KVM on s390x needs to vmalloc a large area, and it needs to be mapped with non-huge pages, because of a hardware limitation. This patch adds the function vmalloc_no_huge, which works like vmalloc, but it is guaranteed to always back the mapping using small pages. This new function is exported, therefore it is usable by modules. [akpm@linux-foundation.org: whitespace fixes, per Christoph] Link: https://lkml.kernel.org/r/20210614132357.10202-1-imbrenda@linux.ibm.com Link: https://lkml.kernel.org/r/20210614132357.10202-2-imbrenda@linux.ibm.com Fixes: 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by: Claudio Imbrenda Reviewed-by: Uladzislau Rezki (Sony) Acked-by: Nicholas Piggin Reviewed-by: David Hildenbrand Acked-by: David Rientjes Cc: Uladzislau Rezki (Sony) Cc: Catalin Marinas Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Christoph Hellwig Cc: Cornelia Huck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: fix typos in comments

2021-05-07T07:26:35+00:00

Fix ~94 single-word typos in locking code comments, plus a few very obvious grammar mistakes. Link: https://lkml.kernel.org/r/20210322212624.GA1963421@gmail.com Link: https://lore.kernel.org/r/20210322205203.GB1959563@gmail.com Signed-off-by: Ingo Molnar Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Randy Dunlap Cc: Bhaskar Chowdhury Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc: remove vwrite()

2021-05-07T07:26:34+00:00

The last user (/dev/kmem) is gone. Let's drop it. Link: https://lkml.kernel.org/r/20210324102351.6932-4-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Michal Hocko Cc: Linus Torvalds Cc: Greg Kroah-Hartman Cc: Hillf Danton Cc: Matthew Wilcox Cc: Oleksiy Avramchenko Cc: Steven Rostedt Cc: Minchan Kim Cc: huang ying Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drivers/char: remove /dev/kmem for good

2021-05-07T07:26:34+00:00

Patch series "drivers/char: remove /dev/kmem for good". Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and memory ballooning, I started questioning the existence of /dev/kmem. Comparing it with the /proc/kcore implementation, it does not seem to be able to deal with things like a) Pages unmapped from the direct mapping (e.g., to be used by secretmem) -> kern_addr_valid(). virt_addr_valid() is not sufficient. b) Special cases like gart aperture memory that is not to be touched -> mem_pfn_is_ram() Unless I am missing something, it's at least broken in some cases and might fault/crash the machine. Looks like its existence has been questioned before in 2005 and 2010 [1], after ~11 additional years, it might make sense to revive the discussion. CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by mistake?). All distributions disable it: in Ubuntu it has been disabled for more than 10 years, in Debian since 2.6.31, in Fedora at least starting with FC3, in RHEL starting with RHEL4, in SUSE starting from 15sp2, and OpenSUSE has it disabled as well. 1) /dev/kmem was popular for rootkits [2] before it got disabled basically everywhere. Ubuntu documents [3] "There is no modern user of /dev/kmem any more beyond attackers using it to load kernel rootkits.". RHEL documents in a BZ [5] "it served no practical purpose other than to serve as a potential security problem or to enable binary module drivers to access structures/functions they shouldn't be touching" 2) /proc/kcore is a decent interface to have a controlled way to read kernel memory for debugging puposes. (will need some extensions to deal with memory offlining/unplug, memory ballooning, and poisoned pages, though) 3) It might be useful for corner case debugging [1]. KDB/KGDB might be a better fit, especially, to write random memory; harder to shoot yourself into the foot. 4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems to be incompatible with 64bit [1]. For educational purposes, /proc/kcore might be used to monitor value updates -- or older kernels can be used. 5) It's broken on arm64, and therefore, completely disabled there. Looks like it's essentially unused and has been replaced by better suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's just remove it. [1] https://lwn.net/Articles/147901/ [2] https://www.linuxjournal.com/article/10505 [3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled [4] https://sourceforge.net/projects/kme/ [5] https://bugzilla.redhat.com/show_bug.cgi?id=154796 Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Michal Hocko Acked-by: Kees Cook Cc: Linus Torvalds Cc: Greg Kroah-Hartman Cc: "Alexander A. Klimov" Cc: Alexander Viro Cc: Alexandre Belloni Cc: Andrew Lunn Cc: Andrey Zhizhikin Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Brian Cain Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Chris Zankel Cc: Corentin Labbe Cc: "David S. Miller" Cc: "Eric W. Biederman" Cc: Geert Uytterhoeven Cc: Gerald Schaefer Cc: Greentime Hu Cc: Gregory Clement Cc: Heiko Carstens Cc: Helge Deller Cc: Hillf Danton Cc: huang ying Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: "James E.J. Bottomley" Cc: James Troup Cc: Jiaxun Yang Cc: Jonas Bonn Cc: Jonathan Corbet Cc: Kairui Song Cc: Krzysztof Kozlowski Cc: Kuninori Morimoto Cc: Liviu Dudau Cc: Lorenzo Pieralisi Cc: Luc Van Oostenryck Cc: Luis Chamberlain Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Mike Rapoport Cc: Mikulas Patocka Cc: Minchan Kim Cc: Niklas Schnelle Cc: Oleksiy Avramchenko Cc: openrisc@lists.librecores.org Cc: Palmer Dabbelt Cc: Paul Mackerras Cc: "Pavel Machek (CIP)" Cc: Pavel Machek Cc: "Peter Zijlstra (Intel)" Cc: Pierre Morel Cc: Randy Dunlap Cc: Richard Henderson Cc: Rich Felker Cc: Robert Richter Cc: Rob Herring Cc: Russell King Cc: Sam Ravnborg Cc: Sebastian Andrzej Siewior Cc: Sebastian Hesselbarth Cc: sparclinux@vger.kernel.org Cc: Stafford Horne Cc: Stefan Kristiansson Cc: Steven Rostedt Cc: Sudeep Holla Cc: Theodore Dubois Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Viresh Kumar Cc: William Cohen Cc: Xiaoming Ni Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/mempool: minor coding style tweaks

2021-05-05T18:27:27+00:00

Various coding style tweaks to various files under mm/ [daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc: remove an empty line

2021-04-30T18:20:40+00:00

Link: https://lkml.kernel.org/r/20210402202237.20334-5-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Cc: Hillf Danton Cc: Matthew Wilcox Cc: Michal Hocko Cc: Oleksiy Avramchenko Cc: Shuah Khan Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc: refactor the preloading loagic

2021-04-30T18:20:40+00:00

Instead of keeping open-coded style, move the code related to preloading into a separate function. Therefore introduce the preload_this_cpu_lock() routine that prelaods a current CPU with one extra vmap_area object. There is no functional change as a result of this patch. Link: https://lkml.kernel.org/r/20210402202237.20334-4-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Cc: Hillf Danton Cc: Matthew Wilcox Cc: Michal Hocko Cc: Oleksiy Avramchenko Cc: Shuah Khan Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: vmalloc: prevent use after free in _vm_unmap_aliases

2021-04-30T18:20:40+00:00

A potential use after free can occur in _vm_unmap_aliases where an already freed vmap_area could be accessed, Consider the following scenario: Process 1 Process 2 __vm_unmap_aliases __vm_unmap_aliases purge_fragmented_blocks_allcpus rcu_read_lock() rcu_read_lock() list_del_rcu(&vb->free_list) list_for_each_entry_rcu(vb .. ) __purge_vmap_area_lazy kmem_cache_free(va) va_start = vb->va->va_start Here Process 1 is in purge path and it does list_del_rcu on vmap_block and later frees the vmap_area, since Process 2 was holding the rcu lock at this time vmap_block will still be present in and Process 2 accesse it and thereby it tries to access vmap_area of that vmap_block which was already freed by Process 1 and this results in use after free. Fix this by adding a check for vb->dirty before accessing vmap_area structure since vb->dirty will be set to VMAP_BBMAP_BITS in purge path checking for this will prevent the use after free. Link: https://lkml.kernel.org/r/1616062105-23263-1-git-send-email-vjitta@codeaurora.org Signed-off-by: Vijayanand Jitta Reviewed-by: Uladzislau Rezki (Sony) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc: improve allocation failure error messages

2021-04-30T18:20:40+00:00

There are several reasons why a vmalloc can fail, virtual space exhausted, page array allocation failure, page allocation failure, and kernel page table allocation failure. Add distinct warning messages for the main causes of failure, with some added information like page order or allocation size where applicable. [urezki@gmail.com: print correct vmalloc allocation size] Link: https://lkml.kernel.org/r/20210329193214.GA28602@pc638.lan Link: https://lkml.kernel.org/r/20210322021806.892164-6-npiggin@gmail.com Signed-off-by: Nicholas Piggin Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Christoph Hellwig Cc: Cédric Le Goater Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds