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* mm: remove the vma linked listLiam R. Howlett2022-09-271-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace any vm_next use with vma_find(). Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the maple tree. Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap(). At the same time, alter the loop to be more compact. Now that free_pgtables() and unmap_vmas() take a maple tree as an argument, rearrange do_mas_align_munmap() to use the new tree to hold the vmas to remove. Remove __vma_link_list() and __vma_unlink_list() as they are exclusively used to update the linked list. Drop linked list update from __insert_vm_struct(). Rework validation of tree as it was depending on the linked list. [yang.lee@linux.alibaba.com: fix one kernel-doc comment] Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1949 Link: https://lkml.kernel.org/r/20220824021918.94116-1-yang.lee@linux.alibaba.comLink: https://lkml.kernel.org/r/20220906194824.2110408-69-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: remove vmacacheLiam R. Howlett2022-09-271-2/+2
| | | | | | | | | | | | | | | | | | | | By using the maple tree and the maple tree state, the vmacache is no longer beneficial and is complicating the VMA code. Remove the vmacache to reduce the work in keeping it up to date and code complexity. Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: unexport page_init_poisonChristoph Hellwig2022-03-251-1/+0
| | | | | | | | | | page_init_poison is only used in core MM code, so unexport it. Link: https://lkml.kernel.org/r/20220207063446.1833404-1-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Turn head_compound_mapcount() into folio_entire_mapcount()Matthew Wilcox (Oracle)2022-03-211-2/+4
| | | | | | | Adjust documentation to be more clear. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
* mm: Make compound_pincount always availableMatthew Wilcox (Oracle)2022-03-211-10/+4
| | | | | | | | | | | | | | | | | Move compound_pincount from the third page to the second page, which means it's available for all compound pages. That lets us delete hpage_pincount_available(). On 32-bit systems, there isn't enough space for both compound_pincount and compound_nr in the second page (it would collide with page->private, which is in use for pages in the swap cache), so revert the optimisation of storing both compound_order and compound_nr on 32-bit systems. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com>
* mm,fs: split dump_mapping() out from dump_page()Matthew Wilcox (Oracle)2022-01-151-50/+2
| | | | | | | | | | | | | | | dump_mapping() is a big chunk of dump_page(), and it'd be handy to be able to call it when we don't have a struct page. Split it out and move it to fs/inode.c. Take the opportunity to simplify some of the debug messages a little. Link: https://lkml.kernel.org/r/20211121121056.2870061-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2021-11-061-9/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge misc updates from Andrew Morton: "257 patches. Subsystems affected by this patch series: scripts, ocfs2, vfs, and mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache, gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools, memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm, vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram, cleanups, kfence, and damon)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits) mm/damon: remove return value from before_terminate callback mm/damon: fix a few spelling mistakes in comments and a pr_debug message mm/damon: simplify stop mechanism Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions Docs/admin-guide/mm/damon/start: simplify the content Docs/admin-guide/mm/damon/start: fix a wrong link Docs/admin-guide/mm/damon/start: fix wrong example commands mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on mm/damon: remove unnecessary variable initialization Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM) selftests/damon: support watermarks mm/damon/dbgfs: support watermarks mm/damon/schemes: activate schemes based on a watermarks mechanism tools/selftests/damon: update for regions prioritization of schemes mm/damon/dbgfs: support prioritization weights mm/damon/vaddr,paddr: support pageout prioritization mm/damon/schemes: prioritize regions within the quotas mm/damon/selftests: support schemes quotas mm/damon/dbgfs: support quotas of schemes ...
| * mm/migrate: de-duplicate migrate_reason stringsJohn Hubbard2021-11-061-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to remove the need to manually keep three different files in synch, provide a common definition of the mapping between enum migrate_reason, and the associated strings for each enum item. 1. Use the tracing system's mapping of enums to strings, by redefining and reusing the MIGRATE_REASON and supporting macros, and using that to populate the string array in mm/debug.c. 2. Move enum migrate_reason to migrate_mode.h. This is not strictly necessary for this patch, but migrate mode and migrate reason go together, so this will slightly clarify things. Link: https://lkml.kernel.org/r/20210922041755.141817-2-jhubbard@nvidia.com Signed-off-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Weizhao Ouyang <o451686892@gmail.com> Cc: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'per_signal_struct_coredumps-for-v5.16' of ↵Linus Torvalds2021-11-031-2/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull per signal_struct coredumps from Eric Biederman: "Current coredumps are mixed up with the exit code, the signal handling code, and the ptrace code making coredumps much more complicated than necessary and difficult to follow. This series of changes starts with ptrace_stop and cleans it up, making it easier to follow what is happening in ptrace_stop. Then cleans up the exec interactions with coredumps. Then cleans up the coredump interactions with exit. Finally the coredump interactions with the signal handling code is cleaned up. The first and last changes are bug fixes for minor bugs. I believe the fact that vfork followed by execve can kill the process the called vfork if exec fails is sufficient justification to change the userspace visible behavior. In previous discussions some of these changes were organized differently and individually appeared to make the code base worse. As currently written I believe they all stand on their own as cleanups and bug fixes. Which means that even if the worst should happen and the last change needs to be reverted for some unimaginable reason, the code base will still be improved. If the worst does not happen there are a more cleanups that can be made. Signals that generate coredumps can easily become eligible for short circuit delivery in complete_signal. The entire rendezvous for generating a coredump can move into get_signal. The function force_sig_info_to_task be written in a way that does not modify the signal handling state of the target task (because coredumps are eligible for short circuit delivery). Many of these future cleanups can be done another way but nothing so cleanly as if coredumps become per signal_struct" * 'per_signal_struct_coredumps-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: coredump: Limit coredumps to a single thread group coredump: Don't perform any cleanups before dumping core exit: Factor coredump_exit_mm out of exit_mm exec: Check for a pending fatal signal instead of core_state ptrace: Remove the unnecessary arguments from arch_ptrace_stop signal: Remove the bogus sigkill_pending in ptrace_stop
| * | coredump: Limit coredumps to a single thread groupEric W. Biederman2021-10-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today when a signal is delivered with a handler of SIG_DFL whose default behavior is to generate a core dump not only that process but every process that shares the mm is killed. In the case of vfork this looks like a real world problem. Consider the following well defined sequence. if (vfork() == 0) { execve(...); _exit(EXIT_FAILURE); } If a signal that generates a core dump is received after vfork but before the execve changes the mm the process that called vfork will also be killed (as the mm is shared). Similarly if the execve fails after the point of no return the kernel delivers SIGSEGV which will kill both the exec'ing process and because the mm is shared the process that called vfork as well. As far as I can tell this behavior is a violation of people's reasonable expectations, POSIX, and is unnecessarily fragile when the system is low on memory. Solve this by making a userspace visible change to only kill a single process/thread group. This is possible because Jann Horn recently modified[1] the coredump code so that the mm can safely be modified while the coredump is happening. With LinuxThreads long gone I don't expect anyone to have a notice this behavior change in practice. To accomplish this move the core_state pointer from mm_struct to signal_struct, which allows different thread groups to coredump simultatenously. In zap_threads remove the work to kill anything except for the current thread group. v2: Remove core_state from the VM_BUG_ON_MM print to fix compile failure when CONFIG_DEBUG_VM is enabled. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> [1] a07279c9a8cd ("binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot") Fixes: d89f3847def4 ("[PATCH] thread-aware coredumps, 2.5.43-C3") History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Link: https://lkml.kernel.org/r/87y27mvnke.fsf@disp2133 Link: https://lkml.kernel.org/r/20211007144701.67592574@canb.auug.org.au Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | | Merge tag 'printk-for-5.16' of ↵Linus Torvalds2021-11-021-1/+1
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Extend %pGp print format to print hex value of the page flags - Use kvmalloc instead of kmalloc to allocate devkmsg buffers - Misc cleanup and warning fixes * tag 'printk-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: vsprintf: Update %pGp documentation about that it prints hex value lib/vsprintf.c: Amend static asserts for format specifier flags vsprintf: Make %pGp print the hex value test_printf: Append strings more efficiently test_printf: Remove custom appending of '|' test_printf: Remove separate page_flags variable test_printf: Make pft array const ia64: don't do IA64_CMPXCHG_DEBUG without CONFIG_PRINTK printk: use gnu_printf format attribute for printk_sprint() printk: avoid -Wsometimes-uninitialized warning printk: use kvmalloc instead of kmalloc for devkmsg_user
| * | vsprintf: Make %pGp print the hex valueMatthew Wilcox (Oracle)2021-10-271-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | All existing users of %pGp want the hex value as well as the decoded flag names. This looks awkward (passing the same parameter to printf twice), so move that functionality into the core. If we want, we can make that optional with flag arguments to %pGp in the future. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Yafang Shao <laoar.shao@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20211019142621.2810043-6-willy@infradead.org
* | mm/debug: sync up latest migrate_reason to migrate_reason_namesWeizhao Ouyang2021-09-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sync up MR_DEMOTION to migrate_reason_names and add a synch prompt. Link: https://lkml.kernel.org/r/20210921064553.293905-3-o451686892@gmail.com Fixes: 26aa2d199d6f ("mm/migrate: demote pages during reclaim") Signed-off-by: Weizhao Ouyang <o451686892@gmail.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mina Almasry <almasrymina@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/debug: sync up MR_CONTIG_RANGE and MR_LONGTERM_PINWeizhao Ouyang2021-09-251-1/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | Sync up MR_CONTIG_RANGE and MR_LONGTERM_PIN to migrate_reason_names. Link: https://lkml.kernel.org/r/20210921064553.293905-2-o451686892@gmail.com Fixes: 310253514bbf ("mm/migrate: rename migration reason MR_CMA to MR_CONTIG_RANGE") Fixes: d1e153fea2a8 ("mm/gup: migrate pinned pages out of movable zone") Signed-off-by: Weizhao Ouyang <o451686892@gmail.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mina Almasry <almasrymina@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Xu <weixugc@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: factor PagePoisoned out of __dump_pageMatthew Wilcox (Oracle)2021-06-291-18/+7
| | | | | | | | | | | | | | Move the PagePoisoned test into dump_page(). Skip the hex print for poisoned pages -- we know they're full of ffffffff. Move the reason printing from __dump_page() to dump_page(). Link: https://lkml.kernel.org/r/20210416231531.2521383-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: make __dump_page staticMatthew Wilcox (Oracle)2021-06-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Constify struct page arguments". While working on various solutions to the 32-bit struct page size regression, one of the problems I found was the networking stack expects to be able to pass const struct page pointers around, and the mm doesn't provide a lot of const-friendly functions to call. The root tangle of problems is that a lot of functions call VM_BUG_ON_PAGE(), which calls dump_page(), which calls a lot of functions which don't take a const struct page (but could be const). This patch (of 6): The only caller of __dump_page() now opencodes dump_page(), so remove it as an externally visible symbol. Link: https://lkml.kernel.org/r/20210416231531.2521383-1-willy@infradead.org Link: https://lkml.kernel.org/r/20210416231531.2521383-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: improve memcg debuggingMatthew Wilcox (Oracle)2021-02-241-5/+5
| | | | | | | | | | | | | | The memcg_data is only valid on the head page, not the tail pages. Change the format and location of the printout within the dump to match the other parts of struct page better. Link: https://lkml.kernel.org/r/20210114190200.1894484-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcontrol: Use helpers to read page's memcg dataRoman Gushchin2020-12-031-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm: allow mapping accounted kernel pages to userspace", v6. Currently a non-slab kernel page which has been charged to a memory cgroup can't be mapped to userspace. The underlying reason is simple: PageKmemcg flag is defined as a page type (like buddy, offline, etc), so it takes a bit from a page->mapped counter. Pages with a type set can't be mapped to userspace. But in general the kmemcg flag has nothing to do with mapping to userspace. It only means that the page has been accounted by the page allocator, so it has to be properly uncharged on release. Some bpf maps are mapping the vmalloc-based memory to userspace, and their memory can't be accounted because of this implementation detail. This patchset removes this limitation by moving the PageKmemcg flag into one of the free bits of the page->mem_cgroup pointer. Also it formalizes accesses to the page->mem_cgroup and page->obj_cgroups using new helpers, adds several checks and removes a couple of obsolete functions. As the result the code became more robust with fewer open-coded bit tricks. This patch (of 4): Currently there are many open-coded reads of the page->mem_cgroup pointer, as well as a couple of read helpers, which are barely used. It creates an obstacle on a way to reuse some bits of the pointer for storing additional bits of information. In fact, we already do this for slab pages, where the last bit indicates that a pointer has an attached vector of objcg pointers instead of a regular memcg pointer. This commits uses 2 existing helpers and introduces a new helper to converts all read sides to calls of these helpers: struct mem_cgroup *page_memcg(struct page *page); struct mem_cgroup *page_memcg_rcu(struct page *page); struct mem_cgroup *page_memcg_check(struct page *page); page_memcg_check() is intended to be used in cases when the page can be a slab page and have a memcg pointer pointing at objcg vector. It does check the lowest bit, and if set, returns NULL. page_memcg() contains a VM_BUG_ON_PAGE() check for the page not being a slab page. To make sure nobody uses a direct access, struct page's mem_cgroup/obj_cgroups is converted to unsigned long memcg_data. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Link: https://lkml.kernel.org/r/20201027001657.3398190-1-guro@fb.com Link: https://lkml.kernel.org/r/20201027001657.3398190-2-guro@fb.com Link: https://lore.kernel.org/bpf/20201201215900.3569844-2-guro@fb.com
* mm, dump_page: rename head_mapcount() --> head_compound_mapcount()John Hubbard2020-10-141-3/+3
| | | | | | | | | | | | | | | | Rename head_pincount() --> head_compound_pincount(). These names are more accurate (or less misleading) than the original ones. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Qian Cai <cai@lca.pw> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: William Kucharski <william.kucharski@oracle.com> Link: https://lkml.kernel.org/r/20200807183358.105097-1-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: do not dereference i_ino blindlyMatthew Wilcox (Oracle)2020-10-141-5/+7
| | | | | | | | | | | | | | | | | __dump_page() checks i_dentry is fetchable and i_ino is earlier in the struct than i_ino, so it ought to work fine, but it's possible that struct randomisation has reordered i_ino after i_dentry and the pointer is just wild enough that i_dentry is fetchable and i_ino isn't. Also print the inode number if the dentry is invalid. Reported-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Link: https://lkml.kernel.org/r/20200819185710.28180-1-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, dump_page: do not crash with bad compound_mapcount()John Hubbard2020-08-071-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a compound page is being split while dump_page() is being run on that page, we can end up calling compound_mapcount() on a page that is no longer compound. This leads to a crash (already seen at least once in the field), due to the VM_BUG_ON_PAGE() assertion inside compound_mapcount(). (The above is from Matthew Wilcox's analysis of Qian Cai's bug report.) A similar problem is possible, via compound_pincount() instead of compound_mapcount(). In order to avoid this kind of crash, make dump_page() slightly more robust, by providing a pair of simpler routines that don't contain assertions: head_mapcount() and head_pincount(). For debug tools, we don't want to go *too* far in this direction, but this is a simple small fix, and the crash has already been seen, so it's a good trade-off. Reported-by: Qian Cai <cai@lca.pw> Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200804214807.169256-1-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: print hashed address of struct pageMatthew Wilcox (Oracle)2020-08-071-4/+4
| | | | | | | | | | | | | | | | | The actual address of the struct page isn't particularly helpful, while the hashed address helps match with other messages elsewhere. Add the PFN that the page refers to in order to help diagnose problems where the page is improperly aligned for the purpose. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200709202117.7216-7-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: print the inode number in dump_pageMatthew Wilcox (Oracle)2020-08-071-3/+3
| | | | | | | | | | | | | | | The inode number helps correlate this page with debug messages elsewhere in the kernel. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200709202117.7216-6-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: switch dump_page to get_kernel_nofaultMatthew Wilcox (Oracle)2020-08-071-20/+16
| | | | | | | | | | | | | | | This is simpler to use than copy_from_kernel_nofault(). Also make some of the related error messages less verbose. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200709202117.7216-5-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: print head flags in dump_pageMatthew Wilcox (Oracle)2020-08-071-1/+1
| | | | | | | | | | | | | | | | | | Tail page flags contain very little useful information. Print the head page's flags instead. While the flags will contain "head" for tail pages, this should not be too confusing as the previous line starts with the word "head:" and so the flags should be interpreted as belonging to the head page. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200709202117.7216-4-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: dump compound page information on a second lineMatthew Wilcox (Oracle)2020-08-071-18/+12
| | | | | | | | | | | | | | | | | Simplify both the implementation and the output by splitting all the compound page information onto a second line. Reported-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200709202117.7216-3-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug: handle page->mapping better in dump_pageMatthew Wilcox (Oracle)2020-08-071-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Improvements for dump_page()", v2. Here's a sample dump of a pagecache tail page with all of the patches applied: page:000000006d1c49ca refcount:6 mapcount:0 mapping:00000000136b8d90 index:0x109 pfn:0x6c645 head:000000008bd38076 order:2 compound_mapcount:0 compound_pincount:0 aops:xfs_address_space_operations ino:800042 dentry name:"fd" flags: 0x4000000000012014(uptodate|lru|private|head) raw: 4000000000000000 ffffd46ac1b19101 ffffffff00000202 dead000000000004 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 head: 4000000000012014 ffffd46ac1b1bbc8 ffffd46ac1b1bc08 ffff91976f659560 head: 0000000000000108 ffff919773220680 00000006ffffffff 0000000000000000 page dumped because: testing This patch (of 6): If we can't call page_mapping() to get the page mapping, handle the anon/ksm/movable bits correctly. [akpm@linux-foundation.org: augmented code comment from John] Link: http://lkml.kernel.org/r/15cff11a-6762-8a6a-3f0e-dd227280cd6f@nvidia.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: William Kucharski <william.kucharski@oracle.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Link: http://lkml.kernel.org/r/20200709202117.7216-1-willy@infradead.org Link: http://lkml.kernel.org/r/20200709202117.7216-2-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofaultChristoph Hellwig2020-06-171-4/+4
| | | | | | | | Better describe what these functions do. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* maccess: always use strict semantics for probe_kernel_readChristoph Hellwig2020-06-091-5/+5
| | | | | | | | | | | | | | | | | | | | Except for historical confusion in the kprobes/uprobes and bpf tracers, which has been fixed now, there is no good reason to ever allow user memory accesses from probe_kernel_read. Switch probe_kernel_read to only read from kernel memory. [akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, dump_page(): do not crash with invalid mapping pointerVlastimil Babka2020-06-021-6/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have seen a following problem on a RPi4 with 1G RAM: BUG: Bad page state in process systemd-hwdb pfn:35601 page:ffff7e0000d58040 refcount:15 mapcount:131221 mapping:efd8fe765bc80080 index:0x1 compound_mapcount: -32767 Unable to handle kernel paging request at virtual address efd8fe765bc80080 Mem abort info: ESR = 0x96000004 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [efd8fe765bc80080] address between user and kernel address ranges Internal error: Oops: 96000004 [#1] SMP Modules linked in: btrfs libcrc32c xor xor_neon zlib_deflate raid6_pq mmc_block xhci_pci xhci_hcd usbcore sdhci_iproc sdhci_pltfm sdhci mmc_core clk_raspberrypi gpio_raspberrypi_exp pcie_brcmstb bcm2835_dma gpio_regulator phy_generic fixed sg scsi_mod efivarfs Supported: No, Unreleased kernel CPU: 3 PID: 408 Comm: systemd-hwdb Not tainted 5.3.18-8-default #1 SLE15-SP2 (unreleased) Hardware name: raspberrypi rpi/rpi, BIOS 2020.01 02/21/2020 pstate: 40000085 (nZcv daIf -PAN -UAO) pc : __dump_page+0x268/0x368 lr : __dump_page+0xc4/0x368 sp : ffff000012563860 x29: ffff000012563860 x28: ffff80003ddc4300 x27: 0000000000000010 x26: 000000000000003f x25: ffff7e0000d58040 x24: 000000000000000f x23: efd8fe765bc80080 x22: 0000000000020095 x21: efd8fe765bc80080 x20: ffff000010ede8b0 x19: ffff7e0000d58040 x18: ffffffffffffffff x17: 0000000000000001 x16: 0000000000000007 x15: ffff000011689708 x14: 3030386362353637 x13: 6566386466653a67 x12: 6e697070616d2031 x11: 32323133313a746e x10: 756f6370616d2035 x9 : ffff00001168a840 x8 : ffff00001077a670 x7 : 000000000000013d x6 : ffff0000118a43b5 x5 : 0000000000000001 x4 : ffff80003dd9e2c8 x3 : ffff80003dd9e2c8 x2 : 911c8d7c2f483500 x1 : dead000000000100 x0 : efd8fe765bc80080 Call trace: __dump_page+0x268/0x368 bad_page+0xd4/0x168 check_new_page_bad+0x80/0xb8 rmqueue_bulk.constprop.26+0x4d8/0x788 get_page_from_freelist+0x4d4/0x1228 __alloc_pages_nodemask+0x134/0xe48 alloc_pages_vma+0x198/0x1c0 do_anonymous_page+0x1a4/0x4d8 __handle_mm_fault+0x4e8/0x560 handle_mm_fault+0x104/0x1e0 do_page_fault+0x1e8/0x4c0 do_translation_fault+0xb0/0xc0 do_mem_abort+0x50/0xb0 el0_da+0x24/0x28 Code: f9401025 8b8018a0 9a851005 17ffffca (f94002a0) Besides the underlying issue with page->mapping containing a bogus value for some reason, we can see that __dump_page() crashed by trying to read the pointer at mapping->host, turning a recoverable warning into full Oops. It can be expected that when page is reported as bad state for some reason, the pointers there should not be trusted blindly. So this patch treats all data in __dump_page() that depends on page->mapping as lava, using probe_kernel_read_strict(). Ideally this would include the dentry->d_parent recursively, but that would mean changing printk handler for %pd. Chances of reaching the dentry printing part with an initially bogus mapping pointer should be rather low, though. Also prefix printing mapping->a_ops with a description of what is being printed. In case the value is bogus, %ps will print raw value instead of the symbol name and then it's not obvious at all that it's printing a_ops. Reported-by: Petr Tesarik <ptesarik@suse.cz> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: John Hubbard <jhubbard@nvidia.com> Link: http://lkml.kernel.org/r/20200331165454.12263-1-vbabka@suse.cz Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: dump_page(): additional diagnostics for huge pinned pagesJohn Hubbard2020-04-021-5/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As part of pin_user_pages() and related API calls, pages are "dma-pinned". For the case of compound pages of order > 1, the per-page accounting of dma pins is accomplished via the 3rd struct page in the compound page. In order to support debugging of any pin_user_pages()- related problems, enhance dump_page() so as to report the pin count in that case. Documentation/core-api/pin_user_pages.rst is also updated accordingly. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-13-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: improve dump_page() for compound pagesMatthew Wilcox (Oracle)2020-04-021-10/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There was no protection against a corrupted struct page having an implausible compound_head(). Sanity check that a compound page has a head within reach of the maximum allocatable page (this will need to be adjusted if one of the plans to allocate 1GB pages comes to fruition). In addition, - Print the mapping pointer using %p insted of %px. The actual value of the pointer can be read out of the raw page dump and using %p gives a chance to correlate it with an earlier printk of the mapping pointer - Print the mapping pointer from the head page, not the tail page (the tail ->mapping pointer may be in use for other purposes, eg part of a list_head) - Print the order of the page for compound pages - Dump the raw head page as well as the raw page - Print the refcount from the head page, not the tail page Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Co-developed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-12-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hotplug: silence a lockdep splat with printk()Qian Cai2020-01-311-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is not that hard to trigger lockdep splats by calling printk from under zone->lock. Most of them are false positives caused by lock chains introduced early in the boot process and they do not cause any real problems (although most of the early boot lock dependencies could happen after boot as well). There are some console drivers which do allocate from the printk context as well and those should be fixed. In any case, false positives are not that trivial to workaround and it is far from optimal to lose lockdep functionality for something that is a non-issue. So change has_unmovable_pages() so that it no longer calls dump_page() itself - instead it returns a "struct page *" of the unmovable page back to the caller so that in the case of a has_unmovable_pages() failure, the caller can call dump_page() after releasing zone->lock. Also, make dump_page() is able to report a CMA page as well, so the reason string from has_unmovable_pages() can be removed. Even though has_unmovable_pages doesn't hold any reference to the returned page this should be reasonably safe for the purpose of reporting the page (dump_page) because it cannot be hotremoved in the context of memory unplug. The state of the page might change but that is the case even with the existing code as zone->lock only plays role for free pages. While at it, remove a similar but unnecessary debug-only printk() as well. A sample of one of those lockdep splats is, WARNING: possible circular locking dependency detected ------------------------------------------------------ test.sh/8653 is trying to acquire lock: ffffffff865a4460 (console_owner){-.-.}, at: console_unlock+0x207/0x750 but task is already holding lock: ffff88883fff3c58 (&(&zone->lock)->rlock){-.-.}, at: __offline_isolated_pages+0x179/0x3e0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&(&zone->lock)->rlock){-.-.}: __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 _raw_spin_lock+0x2f/0x40 rmqueue_bulk.constprop.21+0xb6/0x1160 get_page_from_freelist+0x898/0x22c0 __alloc_pages_nodemask+0x2f3/0x1cd0 alloc_pages_current+0x9c/0x110 allocate_slab+0x4c6/0x19c0 new_slab+0x46/0x70 ___slab_alloc+0x58b/0x960 __slab_alloc+0x43/0x70 __kmalloc+0x3ad/0x4b0 __tty_buffer_request_room+0x100/0x250 tty_insert_flip_string_fixed_flag+0x67/0x110 pty_write+0xa2/0xf0 n_tty_write+0x36b/0x7b0 tty_write+0x284/0x4c0 __vfs_write+0x50/0xa0 vfs_write+0x105/0x290 redirected_tty_write+0x6a/0xc0 do_iter_write+0x248/0x2a0 vfs_writev+0x106/0x1e0 do_writev+0xd4/0x180 __x64_sys_writev+0x45/0x50 do_syscall_64+0xcc/0x76c entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&(&port->lock)->rlock){-.-.}: __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 _raw_spin_lock_irqsave+0x3a/0x50 tty_port_tty_get+0x20/0x60 tty_port_default_wakeup+0xf/0x30 tty_port_tty_wakeup+0x39/0x40 uart_write_wakeup+0x2a/0x40 serial8250_tx_chars+0x22e/0x440 serial8250_handle_irq.part.8+0x14a/0x170 serial8250_default_handle_irq+0x5c/0x90 serial8250_interrupt+0xa6/0x130 __handle_irq_event_percpu+0x78/0x4f0 handle_irq_event_percpu+0x70/0x100 handle_irq_event+0x5a/0x8b handle_edge_irq+0x117/0x370 do_IRQ+0x9e/0x1e0 ret_from_intr+0x0/0x2a cpuidle_enter_state+0x156/0x8e0 cpuidle_enter+0x41/0x70 call_cpuidle+0x5e/0x90 do_idle+0x333/0x370 cpu_startup_entry+0x1d/0x1f start_secondary+0x290/0x330 secondary_startup_64+0xb6/0xc0 -> #1 (&port_lock_key){-.-.}: __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 _raw_spin_lock_irqsave+0x3a/0x50 serial8250_console_write+0x3e4/0x450 univ8250_console_write+0x4b/0x60 console_unlock+0x501/0x750 vprintk_emit+0x10d/0x340 vprintk_default+0x1f/0x30 vprintk_func+0x44/0xd4 printk+0x9f/0xc5 -> #0 (console_owner){-.-.}: check_prev_add+0x107/0xea0 validate_chain+0x8fc/0x1200 __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 console_unlock+0x269/0x750 vprintk_emit+0x10d/0x340 vprintk_default+0x1f/0x30 vprintk_func+0x44/0xd4 printk+0x9f/0xc5 __offline_isolated_pages.cold.52+0x2f/0x30a offline_isolated_pages_cb+0x17/0x30 walk_system_ram_range+0xda/0x160 __offline_pages+0x79c/0xa10 offline_pages+0x11/0x20 memory_subsys_offline+0x7e/0xc0 device_offline+0xd5/0x110 state_store+0xc6/0xe0 dev_attr_store+0x3f/0x60 sysfs_kf_write+0x89/0xb0 kernfs_fop_write+0x188/0x240 __vfs_write+0x50/0xa0 vfs_write+0x105/0x290 ksys_write+0xc6/0x160 __x64_sys_write+0x43/0x50 do_syscall_64+0xcc/0x76c entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: console_owner --> &(&port->lock)->rlock --> &(&zone->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&zone->lock)->rlock); lock(&(&port->lock)->rlock); lock(&(&zone->lock)->rlock); lock(console_owner); *** DEADLOCK *** 9 locks held by test.sh/8653: #0: ffff88839ba7d408 (sb_writers#4){.+.+}, at: vfs_write+0x25f/0x290 #1: ffff888277618880 (&of->mutex){+.+.}, at: kernfs_fop_write+0x128/0x240 #2: ffff8898131fc218 (kn->count#115){.+.+}, at: kernfs_fop_write+0x138/0x240 #3: ffffffff86962a80 (device_hotplug_lock){+.+.}, at: lock_device_hotplug_sysfs+0x16/0x50 #4: ffff8884374f4990 (&dev->mutex){....}, at: device_offline+0x70/0x110 #5: ffffffff86515250 (cpu_hotplug_lock.rw_sem){++++}, at: __offline_pages+0xbf/0xa10 #6: ffffffff867405f0 (mem_hotplug_lock.rw_sem){++++}, at: percpu_down_write+0x87/0x2f0 #7: ffff88883fff3c58 (&(&zone->lock)->rlock){-.-.}, at: __offline_isolated_pages+0x179/0x3e0 #8: ffffffff865a4920 (console_lock){+.+.}, at: vprintk_emit+0x100/0x340 stack backtrace: Hardware name: HPE ProLiant DL560 Gen10/ProLiant DL560 Gen10, BIOS U34 05/21/2019 Call Trace: dump_stack+0x86/0xca print_circular_bug.cold.31+0x243/0x26e check_noncircular+0x29e/0x2e0 check_prev_add+0x107/0xea0 validate_chain+0x8fc/0x1200 __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 console_unlock+0x269/0x750 vprintk_emit+0x10d/0x340 vprintk_default+0x1f/0x30 vprintk_func+0x44/0xd4 printk+0x9f/0xc5 __offline_isolated_pages.cold.52+0x2f/0x30a offline_isolated_pages_cb+0x17/0x30 walk_system_ram_range+0xda/0x160 __offline_pages+0x79c/0xa10 offline_pages+0x11/0x20 memory_subsys_offline+0x7e/0xc0 device_offline+0xd5/0x110 state_store+0xc6/0xe0 dev_attr_store+0x3f/0x60 sysfs_kf_write+0x89/0xb0 kernfs_fop_write+0x188/0x240 __vfs_write+0x50/0xa0 vfs_write+0x105/0x290 ksys_write+0xc6/0x160 __x64_sys_write+0x43/0x50 do_syscall_64+0xcc/0x76c entry_SYSCALL_64_after_hwframe+0x49/0xbe Link: http://lkml.kernel.org/r/20200117181200.20299-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: always print flags in dump_page()Vlastimil Babka2020-01-311-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 76a1850e4572 ("mm/debug.c: __dump_page() prints an extra line") inadvertently removed printing of page flags for pages that are neither anon nor ksm nor have a mapping. Fix that. Using pr_cont() again would be a solution, but the commit explicitly removed its use. Avoiding the danger of mixing up split lines from multiple CPUs might be beneficial for near-panic dumps like this, so fix this without reintroducing pr_cont(). Link: http://lkml.kernel.org/r/9f884d5c-ca60-dc7b-219c-c081c755fab6@suse.cz Fixes: 76a1850e4572 ("mm/debug.c: __dump_page() prints an extra line") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Anshuman Khandual <anshuman.khandual@arm.com> Reported-by: Michal Hocko <mhocko@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Qian Cai <cai@lca.pw> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/mmu_notifier: Rename struct mmu_notifier_mm to mmu_notifier_subscriptionsJason Gunthorpe2020-01-141-2/+2
| | | | | | | | | | | The name mmu_notifier_mm implies that the thing is a mm_struct pointer, and is difficult to abbreviate. The struct is actually holding the interval tree and hlist containing the notifiers subscribed to a mm. Use 'subscriptions' as the variable name for this struct instead of the really terrible and misleading 'mmn_mm'. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* mm/debug.c: PageAnon() is true for PageKsm() pagesRalph Campbell2019-11-161-3/+3
| | | | | | | | | | | | | | | | | | PageAnon() and PageKsm() use the low two bits of the page->mapping pointer to indicate the page type. PageAnon() only checks the LSB while PageKsm() checks the least significant 2 bits are equal to 3. Therefore, PageAnon() is true for KSM pages. __dump_page() incorrectly will never print "ksm" because it checks PageAnon() first. Fix this by checking PageKsm() first. Link: http://lkml.kernel.org/r/20191113000651.20677-1-rcampbell@nvidia.com Fixes: 1c6fb1d89e73 ("mm: print more information about mapping in __dump_page") Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jerome Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: __dump_page() prints an extra lineRalph Campbell2019-11-161-12/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When dumping struct page information, __dump_page() prints the page type with a trailing blank followed by the page flags on a separate line: anon flags: 0x100000000090034(uptodate|lru|active|head|swapbacked) It looks like the intent was to use pr_cont() for printing "flags:" but pr_cont() usage is discouraged so fix this by extending the format to include the flags into a single line: anon flags: 0x100000000090034(uptodate|lru|active|head|swapbacked) If the page is file backed, the name might be long so use two lines: shmem_aops name:"dev/zero" flags: 0x10000000008000c(uptodate|dirty|swapbacked) Eliminate pr_conf() usage as well for appending compound_mapcount. Link: http://lkml.kernel.org/r/20191112012608.16926-1-rcampbell@nvidia.com Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: update references to page _refcountBaruch Siach2019-05-151-1/+1
| | | | | | | | | | | | | | Commit 0139aa7b7fa ("mm: rename _count, field of the struct page, to _refcount") left out a couple of references to the old field name. Fix that. Link: http://lkml.kernel.org/r/cedf87b02eb8a6b3eac57e8e91da53fb15c3c44c.1556537475.git.baruch@tkos.co.il Fixes: 0139aa7b7fa ("mm: rename _count, field of the struct page, to _refcount") Signed-off-by: Baruch Siach <baruch@tkos.co.il> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: fix __dump_page when mapping->host is not setOscar Salvador2019-03-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While debugging something, I added a dump_page() into do_swap_page(), and I got the splat from below. The issue happens when dereferencing mapping->host in __dump_page(): ... else if (mapping) { pr_warn("%ps ", mapping->a_ops); if (mapping->host->i_dentry.first) { struct dentry *dentry; dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias); pr_warn("name:\"%pd\" ", dentry); } } ... Swap address space does not contain an inode information, and so mapping->host equals NULL. Although the dump_page() call was added artificially into do_swap_page(), I am not sure if we can hit this from any other path, so it looks worth fixing it. We can easily do that by checking mapping->host first. Link: http://lkml.kernel.org/r/20190318072931.29094-1-osalvador@suse.de Fixes: 1c6fb1d89e73c ("mm: print more information about mapping in __dump_page") Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: add a cast to u64 for atomic64_read()Qian Cai2019-03-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | atomic64_read() on ppc64le returns "long int", so fix the same way as commit d549f545e690 ("drm/virtio: use %llu format string form atomic64_t") by adding a cast to u64, which makes it work on all arches. In file included from ./include/linux/printk.h:7, from ./include/linux/kernel.h:15, from mm/debug.c:9: mm/debug.c: In function 'dump_mm': ./include/linux/kern_levels.h:5:18: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 19 has type 'long int' [-Wformat=] #define KERN_SOH "A" /* ASCII Start Of Header */ ^~~~~~ ./include/linux/kern_levels.h:8:20: note: in expansion of macro 'KERN_SOH' #define KERN_EMERG KERN_SOH "0" /* system is unusable */ ^~~~~~~~ ./include/linux/printk.h:297:9: note: in expansion of macro 'KERN_EMERG' printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__) ^~~~~~~~~~ mm/debug.c:133:2: note: in expansion of macro 'pr_emerg' pr_emerg("mm %px mmap %px seqnum %llu task_size %lu" ^~~~~~~~ mm/debug.c:140:17: note: format string is defined here "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx" ~~~^ %lx Link: http://lkml.kernel.org/r/20190310183051.87303-1-cai@lca.pw Fixes: 70f8a3ca68d3 ("mm: make mm->pinned_vm an atomic64 counter") Signed-off-by: Qian Cai <cai@lca.pw> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdmaLinus Torvalds2019-03-101-2/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull rdma updates from Jason Gunthorpe: "This has been a slightly more active cycle than normal with ongoing core changes and quite a lot of collected driver updates. - Various driver fixes for bnxt_re, cxgb4, hns, mlx5, pvrdma, rxe - A new data transfer mode for HFI1 giving higher performance - Significant functional and bug fix update to the mlx5 On-Demand-Paging MR feature - A chip hang reset recovery system for hns - Change mm->pinned_vm to an atomic64 - Update bnxt_re to support a new 57500 chip - A sane netlink 'rdma link add' method for creating rxe devices and fixing the various unregistration race conditions in rxe's unregister flow - Allow lookup up objects by an ID over netlink - Various reworking of the core to driver interface: - drivers should not assume umem SGLs are in PAGE_SIZE chunks - ucontext is accessed via udata not other means - start to make the core code responsible for object memory allocation - drivers should convert struct device to struct ib_device via a helper - drivers have more tools to avoid use after unregister problems" * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (280 commits) net/mlx5: ODP support for XRC transport is not enabled by default in FW IB/hfi1: Close race condition on user context disable and close RDMA/umem: Revert broken 'off by one' fix RDMA/umem: minor bug fix in error handling path RDMA/hns: Use GFP_ATOMIC in hns_roce_v2_modify_qp cxgb4: kfree mhp after the debug print IB/rdmavt: Fix concurrency panics in QP post_send and modify to error IB/rdmavt: Fix loopback send with invalidate ordering IB/iser: Fix dma_nents type definition IB/mlx5: Set correct write permissions for implicit ODP MR bnxt_re: Clean cq for kernel consumers only RDMA/uverbs: Don't do double free of allocated PD RDMA: Handle ucontext allocations by IB/core RDMA/core: Fix a WARN() message bnxt_re: fix the regression due to changes in alloc_pbl IB/mlx4: Increase the timeout for CM cache IB/core: Abort page fault handler silently during owning process exit IB/mlx5: Validate correct PD before prefetch MR IB/mlx5: Protect against prefetch of invalid MR RDMA/uverbs: Store PR pointer before it is overwritten ...
| * mm: make mm->pinned_vm an atomic64 counterDavidlohr Bueso2019-02-071-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Taking a sleeping lock to _only_ increment a variable is quite the overkill, and pretty much all users do this. Furthermore, some drivers (ie: infiniband and scif) that need pinned semantics can go to quite some trouble to actually delay via workqueue (un)accounting for pinned pages when not possible to acquire it. By making the counter atomic we no longer need to hold the mmap_sem and can simply some code around it for pinned_vm users. The counter is 64-bit such that we need not worry about overflows such as rdma user input controlled from userspace. Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Christoph Lameter <cl@linux.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* | mm/debug.c: fix __dump_page() for poisoned pagesRobin Murphy2019-02-211-1/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Evaluating page_mapping() on a poisoned page ends up dereferencing junk and making PF_POISONED_CHECK() considerably crashier than intended: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000006 Mem abort info: ESR = 0x96000005 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c2f6ac38 [0000000000000006] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 2 PID: 491 Comm: bash Not tainted 5.0.0-rc1+ #1 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Dec 17 2018 pstate: 00000005 (nzcv daif -PAN -UAO) pc : page_mapping+0x18/0x118 lr : __dump_page+0x1c/0x398 Process bash (pid: 491, stack limit = 0x000000004ebd4ecd) Call trace: page_mapping+0x18/0x118 __dump_page+0x1c/0x398 dump_page+0xc/0x18 remove_store+0xbc/0x120 dev_attr_store+0x18/0x28 sysfs_kf_write+0x40/0x50 kernfs_fop_write+0x130/0x1d8 __vfs_write+0x30/0x180 vfs_write+0xb4/0x1a0 ksys_write+0x60/0xd0 __arm64_sys_write+0x18/0x20 el0_svc_common+0x94/0xf8 el0_svc_handler+0x68/0x70 el0_svc+0x8/0xc Code: f9400401 d1000422 f240003f 9a801040 (f9400402) ---[ end trace cdb5eb5bf435cecb ]--- Fix that by not inspecting the mapping until we've determined that it's likely to be valid. Now the above condition still ends up stopping the kernel, but in the correct manner: page:ffffffbf20000000 is uninitialized and poisoned raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) ------------[ cut here ]------------ kernel BUG at ./include/linux/mm.h:1006! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 483 Comm: bash Not tainted 5.0.0-rc1+ #3 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Dec 17 2018 pstate: 40000005 (nZcv daif -PAN -UAO) pc : remove_store+0xbc/0x120 lr : remove_store+0xbc/0x120 ... Link: http://lkml.kernel.org/r/03b53ee9d7e76cda4b9b5e1e31eea080db033396.1550071778.git.robin.murphy@arm.com Fixes: 1c6fb1d89e73 ("mm: print more information about mapping in __dump_page") Signed-off-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: make "migrate_reason_names[]" const char *Alexey Dobriyan2018-12-281-1/+1
| | | | | | | | | | | | Those strings are immutable as well. Link: http://lkml.kernel.org/r/20181124090508.GB10877@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: lower the printk loglevel for __dump_page messagesMichal Hocko2018-12-281-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | __dump_page messages use KERN_EMERG resp. KERN_ALERT loglevel (this is the case since 2004). Most callers of this function are really detecting a critical page state and BUG right after. On the other hand the function is called also from contexts which just want to inform about the page state and those would rather not disrupt logs that much (e.g. some systems route these messages to the normal console). Reduce the loglevel to KERN_WARNING to make dump_page easier to reuse for other contexts while those messages will still make it to the kernel log in most setups. Even if the loglevel setup filters warnings away those paths that are really critical already print the more targeted error or panic and that should make it to the kernel log. [mhocko@kernel.org: fix __dump_page()] Link: http://lkml.kernel.org/r/20181212142540.GA7378@dhcp22.suse.cz [akpm@linux-foundation.org: s/KERN_WARN/KERN_WARNING/, per Michal] Link: http://lkml.kernel.org/r/20181107101830.17405-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <OSalvador@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: print more information about mapping in __dump_pageMichal Hocko2018-12-281-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I have been promissing to improve memory offlining failures debugging for quite some time. As things stand now we get only very limited information in the kernel log when the offlining fails. It is usually only [ 1984.506184] rac1 kernel: memory offlining [mem 0x82600000000-0x8267fffffff] failed with no further details. We do not know what exactly fails and for what reason. Whenever I was forced to debug such a failure I've always had to do a debugging patch to tell me more. We can enable some tracepoints but it would be much better to get a better picture without using them. This patch series does 2 things. The first one is to make dump_page more usable by printing more information about the mapping patch 1. Then it reduces the log level from emerg to warning so that this function is usable from less critical context patch 2. Then I have added more detailed information about the offlining failure patch 4 and finally add dump_page to isolation and offlining migration paths. Patch 3 is a trivial cleanup. This patch (of 6): __dump_page prints the mapping pointer but that is quite unhelpful for many reports because the pointer itself only helps to distinguish anon/ksm mappings from other ones (because of lowest bits set). Sometimes it would be much more helpful to know what kind of mapping that is actually and if we know this is a file mapping then also try to resolve the dentry name. [dan.carpenter@oracle.com: fix a width vs precision bug in printk] Link: http://lkml.kernel.org/r/20181123072135.gqvblm2vdujbvfjs@kili.mountain [mhocko@kernel.org: use %dp to print dentry] Link: http://lkml.kernel.org/r/20181125080834.GB12455@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20181107101830.17405-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Cc: Oscar Salvador <OSalvador@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: provide kernel parameter to allow disabling page init poisoningAlexander Duyck2018-10-271-0/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Address issues slowing persistent memory initialization", v5. The main thing this patch set achieves is that it allows us to initialize each node worth of persistent memory independently. As a result we reduce page init time by about 2 minutes because instead of taking 30 to 40 seconds per node and going through each node one at a time, we process all 4 nodes in parallel in the case of a 12TB persistent memory setup spread evenly over 4 nodes. This patch (of 3): On systems with a large amount of memory it can take a significant amount of time to initialize all of the page structs with the PAGE_POISON_PATTERN value. I have seen it take over 2 minutes to initialize a system with over 12TB of RAM. In order to work around the issue I had to disable CONFIG_DEBUG_VM and then the boot time returned to something much more reasonable as the arch_add_memory call completed in milliseconds versus seconds. However in doing that I had to disable all of the other VM debugging on the system. In order to work around a kernel that might have CONFIG_DEBUG_VM enabled on a system that has a large amount of memory I have added a new kernel parameter named "vm_debug" that can be set to "-" in order to disable it. Link: http://lkml.kernel.org/r/20180925201921.3576.84239.stgit@localhost.localdomain Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: get rid of vmacache_flush_all() entirelyLinus Torvalds2018-09-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Jann Horn points out that the vmacache_flush_all() function is not only potentially expensive, it's buggy too. It also happens to be entirely unnecessary, because the sequence number overflow case can be avoided by simply making the sequence number be 64-bit. That doesn't even grow the data structures in question, because the other adjacent fields are already 64-bit. So simplify the whole thing by just making the sequence number overflow case go away entirely, which gets rid of all the complications and makes the code faster too. Win-win. [ Oleg Nesterov points out that the VMACACHE_FULL_FLUSHES statistics also just goes away entirely with this ] Reported-by: Jann Horn <jannh@google.com> Suggested-by: Will Deacon <will.deacon@arm.com> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: teach dump_page() to correctly output poisoned struct pagesPavel Tatashin2018-07-041-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | If struct page is poisoned, and uninitialized access is detected via PF_POISONED_CHECK(page) dump_page() is called to output the page. But, the dump_page() itself accesses struct page to determine how to print it, and therefore gets into a recursive loop. For example: dump_page() __dump_page() PageSlab(page) PF_POISONED_CHECK(page) VM_BUG_ON_PGFLAGS(PagePoisoned(page), page) dump_page() recursion loop. Link: http://lkml.kernel.org/r/20180702180536.2552-1-pasha.tatashin@oracle.com Fixes: f165b378bbdf ("mm: uninitialized struct page poisoning sanity checking") Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: provide useful debugging information for VM_BUGMatthew Wilcox2018-01-051-14/+14
| | | | | | | | | | | | | | | With the recent addition of hashed kernel pointers, places which need to produce useful debug output have to specify %px, not %p. This patch fixes all the VM debug to use %px. This is appropriate because it's debug output that the user should never be able to trigger, and kernel developers need to see the actual pointers. Link: http://lkml.kernel.org/r/20171219133236.GE13680@bombadil.infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: "Tobin C. Harding" <me@tobin.cc> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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