user/sven/linux.git/include/linux/slab.h, branch v4.4.162

mm, slab: make sure that KMALLOC_MAX_SIZE will fit into MAX_ORDER

2017-08-11T16:08:58Z

[ Upstream commit bb1107f7c6052c863692a41f78c000db792334bf ] Andrey Konovalov has reported the following warning triggered by the syzkaller fuzzer. WARNING: CPU: 1 PID: 9935 at mm/page_alloc.c:3511 __alloc_pages_nodemask+0x159c/0x1e20 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 9935 Comm: syz-executor0 Not tainted 4.9.0-rc7+ #34 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __alloc_pages_slowpath mm/page_alloc.c:3511 __alloc_pages_nodemask+0x159c/0x1e20 mm/page_alloc.c:3781 alloc_pages_current+0x1c7/0x6b0 mm/mempolicy.c:2072 alloc_pages include/linux/gfp.h:469 kmalloc_order+0x1f/0x70 mm/slab_common.c:1015 kmalloc_order_trace+0x1f/0x160 mm/slab_common.c:1026 kmalloc_large include/linux/slab.h:422 __kmalloc+0x210/0x2d0 mm/slub.c:3723 kmalloc include/linux/slab.h:495 ep_write_iter+0x167/0xb50 drivers/usb/gadget/legacy/inode.c:664 new_sync_write fs/read_write.c:499 __vfs_write+0x483/0x760 fs/read_write.c:512 vfs_write+0x170/0x4e0 fs/read_write.c:560 SYSC_write fs/read_write.c:607 SyS_write+0xfb/0x230 fs/read_write.c:599 entry_SYSCALL_64_fastpath+0x1f/0xc2 The issue is caused by a lack of size check for the request size in ep_write_iter which should be fixed. It, however, points to another problem, that SLUB defines KMALLOC_MAX_SIZE too large because the its KMALLOC_SHIFT_MAX is (MAX_ORDER + PAGE_SHIFT) which means that the resulting page allocator request might be MAX_ORDER which is too large (see __alloc_pages_slowpath). The same applies to the SLOB allocator which allows even larger sizes. Make sure that they are capped properly and never request more than MAX_ORDER order. Link: http://lkml.kernel.org/r/20161220130659.16461-2-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Andrey Konovalov Acked-by: Christoph Lameter Cc: Alexei Starovoitov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

slab/slub: adjust kmem_cache_alloc_bulk API

2015-11-22T19:58:44Z

Adjust kmem_cache_alloc_bulk API before we have any real users. Adjust API to return type 'int' instead of previously type 'bool'. This is done to allow future extension of the bulk alloc API. A future extension could be to allow SLUB to stop at a page boundary, when specified by a flag, and then return the number of objects. The advantage of this approach, would make it easier to make bulk alloc run without local IRQs disabled. With an approach of cmpxchg "stealing" the entire c->freelist or page->freelist. To avoid overshooting we would stop processing at a slab-page boundary. Else we always end up returning some objects at the cost of another cmpxchg. To keep compatible with future users of this API linking against an older kernel when using the new flag, we need to return the number of allocated objects with this API change. Signed-off-by: Jesper Dangaard Brouer Cc: Vladimir Davydov Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

slab.h: sprinkle __assume_aligned attributes

2015-11-21T00:17:32Z

The various allocators return aligned memory. Telling the compiler that allows it to generate better code in many cases, for example when the return value is immediately passed to memset(). Some code does become larger, but at least we win twice as much as we lose: $ scripts/bloat-o-meter /tmp/vmlinux vmlinux add/remove: 0/0 grow/shrink: 13/52 up/down: 995/-2140 (-1145) An example of the different (and smaller) code can be seen in mm_alloc(). Before: : 48 8d 78 08 lea 0x8(%rax),%rdi : 48 89 c1 mov %rax,%rcx : 48 89 c2 mov %rax,%rdx : 48 c7 00 00 00 00 00 movq $0x0,(%rax) : 48 c7 80 48 03 00 00 movq $0x0,0x348(%rax) : 00 00 00 00 : 31 c0 xor %eax,%eax : 48 83 e7 f8 and $0xfffffffffffffff8,%rdi : 48 29 f9 sub %rdi,%rcx : 81 c1 50 03 00 00 add $0x350,%ecx : c1 e9 03 shr $0x3,%ecx : f3 48 ab rep stos %rax,%es:(%rdi) After: : 48 89 c2 mov %rax,%rdx : b9 6a 00 00 00 mov $0x6a,%ecx : 31 c0 xor %eax,%eax : 48 89 d7 mov %rdx,%rdi : f3 48 ab rep stos %rax,%es:(%rdi) So gcc's strategy is to do two possibly (but not really, of course) unaligned stores to the first and last word, then do an aligned rep stos covering the middle part with a little overlap. Maybe arches which do not allow unaligned stores gain even more. I don't know if gcc can actually make use of alignments greater than 8 for anything, so one could probably drop the __assume_xyz_alignment macros and just use __assume_aligned(8). The increases in code size are mostly caused by gcc deciding to opencode strlen() using the check-four-bytes-at-a-time trick when it knows the buffer is sufficiently aligned (one function grew by 200 bytes). Now it turns out that many of these strlen() calls showing up were in fact redundant, and they're gone from -next. Applying the two patches to next-20151001 bloat-o-meter instead says add/remove: 0/0 grow/shrink: 6/52 up/down: 244/-2140 (-1896) Signed-off-by: Rasmus Villemoes Acked-by: Christoph Lameter Cc: David Rientjes Cc: Pekka Enberg Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

slab: convert slab_is_available() to boolean

2015-11-06T03:34:48Z

A good candidate to return a boolean result. Signed-off-by: Denis Kirjanov Cc: Christoph Lameter Reviewed-by: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

slab: infrastructure for bulk object allocation and freeing

2015-09-04T23:54:41Z

Add the basic infrastructure for alloc/free operations on pointer arrays. It includes a generic function in the common slab code that is used in this infrastructure patch to create the unoptimized functionality for slab bulk operations. Allocators can then provide optimized allocation functions for situations in which large numbers of objects are needed. These optimization may avoid taking locks repeatedly and bypass metadata creation if all objects in slab pages can be used to provide the objects required. Allocators can extend the skeletons provided and add their own code to the bulk alloc and free functions. They can keep the generic allocation and freeing and just fall back to those if optimizations would not work (like for example when debugging is on). Signed-off-by: Christoph Lameter Signed-off-by: Jesper Dangaard Brouer Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Fix kmalloc slab creation sequence

2015-06-29T17:49:51Z

This patch restores the slab creation sequence that was broken by commit 4066c33d0308f8 and also reverts the portions that introduced the KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation is much more complex than just going from a minimum to a maximum number. The latest upstream kernel boots cleanly on my machine with a 64 bit x86 configuration under KVM using either SLAB or SLUB. Fixes: 4066c33d0308f8 ("support the slub_debug boot option") Reported-by: Theodore Ts'o Signed-off-by: Christoph Lameter Signed-off-by: Linus Torvalds

linux/slab.h: fix three off-by-one typos in comment

2015-06-25T00:49:41Z

The first is a keyboard-off-by-one, the other two the ordinary mathy kind. Signed-off-by: Rasmus Villemoes Acked-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/slab_common: support the slub_debug boot option on specific object size

2015-06-25T00:49:40Z

The slub_debug=PU,kmalloc-xx cannot work because in the create_kmalloc_caches() the s->name is created after the create_kmalloc_cache() is called. The name is NULL in the create_kmalloc_cache() so the kmem_cache_flags() would not set the slub_debug flags to the s->flags. The fix here set up a kmalloc_names string array for the initialization purpose and delete the dynamic name creation of kmalloc_caches. [akpm@linux-foundation.org: s/kmalloc_names/kmalloc_info/, tweak comment text] Signed-off-by: Gavin Guo Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, slab: correct config option in comment

2015-04-14T23:48:59Z

CONFIG_SLAB_DEBUG doesn't exist, CONFIG_DEBUG_SLAB does. Signed-off-by: David Rientjes Cc: Christoph Lameter Cc: Pekka Enberg Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: slub: add kernel address sanitizer support for slub allocator

2015-02-14T05:21:41Z

With this patch kasan will be able to catch bugs in memory allocated by slub. Initially all objects in newly allocated slab page, marked as redzone. Later, when allocation of slub object happens, requested by caller number of bytes marked as accessible, and the rest of the object (including slub's metadata) marked as redzone (inaccessible). We also mark object as accessible if ksize was called for this object. There is some places in kernel where ksize function is called to inquire size of really allocated area. Such callers could validly access whole allocated memory, so it should be marked as accessible. Code in slub.c and slab_common.c files could validly access to object's metadata, so instrumentation for this files are disabled. Signed-off-by: Andrey Ryabinin Signed-off-by: Dmitry Chernenkov Cc: Dmitry Vyukov Cc: Konstantin Serebryany Signed-off-by: Andrey Konovalov Cc: Yuri Gribov Cc: Konstantin Khlebnikov Cc: Sasha Levin Cc: Christoph Lameter Cc: Joonsoo Kim Cc: Dave Hansen Cc: Andi Kleen Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds