kernel/linux.git/mm/slab.c, branch linux-5.17.y

mm, kfence: support kmem_dump_obj() for KFENCE objects

2022-04-20T07:36:27+00:00

commit 2dfe63e61cc31ee59ce951672b0850b5229cd5b0 upstream. Calling kmem_obj_info() via kmem_dump_obj() on KFENCE objects has been producing garbage data due to the object not actually being maintained by SLAB or SLUB. Fix this by implementing __kfence_obj_info() that copies relevant information to struct kmem_obj_info when the object was allocated by KFENCE; this is called by a common kmem_obj_info(), which also calls the slab/slub/slob specific variant now called __kmem_obj_info(). For completeness, kmem_dump_obj() now displays if the object was allocated by KFENCE. Link: https://lore.kernel.org/all/20220323090520.GG16885@xsang-OptiPlex-9020/ Link: https://lkml.kernel.org/r/20220406131558.3558585-1-elver@google.com Fixes: b89fb5ef0ce6 ("mm, kfence: insert KFENCE hooks for SLUB") Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB") Signed-off-by: Marco Elver Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reported-by: kernel test robot Acked-by: Vlastimil Babka [slab] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: kfence: fix missing objcg housekeeping for SLAB

2022-04-08T11:57:12+00:00

commit ae085d7f9365de7da27ab5c0d16b12d51ea7fca9 upstream. The objcg is not cleared and put for kfence object when it is freed, which could lead to memory leak for struct obj_cgroup and wrong statistics of NR_SLAB_RECLAIMABLE_B or NR_SLAB_UNRECLAIMABLE_B. Since the last freed object's objcg is not cleared, mem_cgroup_from_obj() could return the wrong memcg when this kfence object, which is not charged to any objcgs, is reallocated to other users. A real word issue [1] is caused by this bug. Link: https://lore.kernel.org/all/000000000000cabcb505dae9e577@google.com/ [1] Reported-by: syzbot+f8c45ccc7d5d45fc5965@syzkaller.appspotmail.com Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB") Signed-off-by: Muchun Song Cc: Dmitry Vyukov Cc: Marco Elver Cc: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/kasan: Convert to struct folio and struct slab

2022-01-06T11:26:14+00:00

KASAN accesses some slab related struct page fields so we need to convert it to struct slab. Some places are a bit simplified thanks to kasan_addr_to_slab() encapsulating the PageSlab flag check through virt_to_slab(). When resolving object address to either a real slab or a large kmalloc, use struct folio as the intermediate type for testing the slab flag to avoid unnecessary implicit compound_head(). [ vbabka@suse.cz: use struct folio, adjust to differences in previous patches ] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Vlastimil Babka Reviewed-by: Andrey Konovalov Reviewed-by: Roman Gushchin Tested-by: Hyeongogn Yoo <42.hyeyoo@gmail.com> Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc:

mm: Convert struct page to struct slab in functions used by other subsystems

2022-01-06T11:26:13+00:00

KASAN, KFENCE and memcg interact with SLAB or SLUB internals through functions nearest_obj(), obj_to_index() and objs_per_slab() that use struct page as parameter. This patch converts it to struct slab including all callers, through a coccinelle semantic patch. // Options: --include-headers --no-includes --smpl-spacing include/linux/slab_def.h include/linux/slub_def.h mm/slab.h mm/kasan/*.c mm/kfence/kfence_test.c mm/memcontrol.c mm/slab.c mm/slub.c // Note: needs coccinelle 1.1.1 to avoid breaking whitespace @@ @@ -objs_per_slab_page( +objs_per_slab( ... ) { ... } @@ @@ -objs_per_slab_page( +objs_per_slab( ... ) @@ identifier fn =~ "obj_to_index|objs_per_slab"; @@ fn(..., - const struct page *page + const struct slab *slab ,...) { <... ( - page_address(page) + slab_address(slab) | - page + slab ) ...> } @@ identifier fn =~ "nearest_obj"; @@ fn(..., - struct page *page + const struct slab *slab ,...) { <... ( - page_address(page) + slab_address(slab) | - page + slab ) ...> } @@ identifier fn =~ "nearest_obj|obj_to_index|objs_per_slab"; expression E; @@ fn(..., ( - slab_page(E) + E | - virt_to_page(E) + virt_to_slab(E) | - virt_to_head_page(E) + virt_to_slab(E) | - page + page_slab(page) ) ,...) Signed-off-by: Vlastimil Babka Reviewed-by: Andrey Konovalov Reviewed-by: Roman Gushchin Acked-by: Johannes Weiner Cc: Julia Lawall Cc: Luis Chamberlain Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Marco Elver Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Cc:

mm/slab: Finish struct page to struct slab conversion

2022-01-06T11:26:10+00:00

Change cache_free_alien() to use slab_nid(virt_to_slab()). Otherwise just update of comments and some remaining variable names. Signed-off-by: Vlastimil Babka Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Roman Gushchin

mm/slab: Convert most struct page to struct slab by spatch

2022-01-06T11:26:02+00:00

The majority of conversion from struct page to struct slab in SLAB internals can be delegated to a coccinelle semantic patch. This includes renaming of variables with 'page' in name to 'slab', and similar. Big thanks to Julia Lawall and Luis Chamberlain for help with coccinelle. // Options: --include-headers --no-includes --smpl-spacing mm/slab.c // Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the // embedded script // build list of functions for applying the next rule @initialize:ocaml@ @@ let ok_function p = not (List.mem (List.hd p).current_element ["kmem_getpages";"kmem_freepages"]) // convert the type in selected functions @@ position p : script:ocaml() { ok_function p }; @@ - struct page@p + struct slab @@ @@ -PageSlabPfmemalloc(page) +slab_test_pfmemalloc(slab) @@ @@ -ClearPageSlabPfmemalloc(page) +slab_clear_pfmemalloc(slab) @@ @@ obj_to_index( ..., - page + slab_page(slab) ,...) // for all functions, change any "struct slab *page" parameter to "struct slab // *slab" in the signature, and generally all occurences of "page" to "slab" in // the body - with some special cases. @@ identifier fn; expression E; @@ fn(..., - struct slab *page + struct slab *slab ,...) { <... ( - int page_node; + int slab_node; | - page_node + slab_node | - page_slab(page) + slab | - page_address(page) + slab_address(slab) | - page_size(page) + slab_size(slab) | - page_to_nid(page) + slab_nid(slab) | - virt_to_head_page(E) + virt_to_slab(E) | - page + slab ) ...> } // rename a function parameter @@ identifier fn; expression E; @@ fn(..., - int page_node + int slab_node ,...) { <... - page_node + slab_node ...> } // functions converted by previous rules that were temporarily called using // slab_page(E) so we want to remove the wrapper now that they accept struct // slab ptr directly @@ identifier fn =~ "index_to_obj"; expression E; @@ fn(..., - slab_page(E) + E ,...) // functions that were returning struct page ptr and now will return struct // slab ptr, including slab_page() wrapper removal @@ identifier fn =~ "cache_grow_begin|get_valid_first_slab|get_first_slab"; expression E; @@ fn(...) { <... - slab_page(E) + E ...> } // rename any former struct page * declarations @@ @@ struct slab * -page +slab ; // all functions (with exceptions) with a local "struct slab *page" variable // that will be renamed to "struct slab *slab" @@ identifier fn !~ "kmem_getpages|kmem_freepages"; expression E; @@ fn(...) { <... ( - page_slab(page) + slab | - page_to_nid(page) + slab_nid(slab) | - kasan_poison_slab(page) + kasan_poison_slab(slab_page(slab)) | - page_address(page) + slab_address(slab) | - page_size(page) + slab_size(slab) | - page->pages + slab->slabs | - page = virt_to_head_page(E) + slab = virt_to_slab(E) | - virt_to_head_page(E) + virt_to_slab(E) | - page + slab ) ...> } Signed-off-by: Vlastimil Babka Reviewed-by: Roman Gushchin Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Julia Lawall Cc: Luis Chamberlain

mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab

2022-01-06T11:26:02+00:00

These functions sit at the boundary to page allocator. Also use folio internally to avoid extra compound_head() when dealing with page flags. Signed-off-by: Vlastimil Babka Reviewed-by: Roman Gushchin Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

mm: Convert check_heap_object() to use struct slab

2022-01-06T11:25:51+00:00

Ensure that we're not seeing a tail page inside __check_heap_object() by converting to a slab instead of a page. Take the opportunity to mark the slab as const since we're not modifying it. Also move the declaration of __check_heap_object() to mm/slab.h so it's not available to the wider kernel. [ vbabka@suse.cz: in check_heap_object() only convert to struct slab for actual PageSlab pages; use folio as intermediate step instead of page ] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Vlastimil Babka Reviewed-by: Roman Gushchin

mm: Use struct slab in kmem_obj_info()

2022-01-06T11:25:51+00:00

All three implementations of slab support kmem_obj_info() which reports details of an object allocated from the slab allocator. By using the slab type instead of the page type, we make it obvious that this can only be called for slabs. [ vbabka@suse.cz: also convert the related kmem_valid_obj() to folios ] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Vlastimil Babka Reviewed-by: Roman Gushchin

mm: Convert [un]account_slab_page() to struct slab

2022-01-06T11:25:40+00:00

Convert the parameter of these functions to struct slab instead of struct page and drop _page from the names. For now their callers just convert page to slab. [ vbabka@suse.cz: replace existing functions instead of calling them ] Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Vlastimil Babka Acked-by: Johannes Weiner Reviewed-by: Roman Gushchin