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mm, slub: validate slab from partial list or page allocator before making it cpu slab 

When we obtain a new slab page from node partial list or page allocator, we
assign it to kmem_cache_cpu, perform some checks, and if they fail, we undo
the assignment.

In order to allow doing the checks without irq disabled, restructure the code
so that the checks are done first, and kmem_cache_cpu.page assignment only
after they pass.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Vlastimil Babka 2021-05-11 16:37:51 +02:00
parent 6c1dbb674c
commit 3f2b77e35a
1 changed files with 9 additions and 8 deletions
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17
mm/slub.c
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@ -2802,10 +2802,8 @@ new_objects:
lockdep_assert_irqs_disabled();
freelist = get_partial(s, gfpflags, node, &page);
if (freelist) {
c->page = page;
if (freelist)
goto check_new_page;
}
local_irq_restore(flags);
put_cpu_ptr(s->cpu_slab);
@ -2818,9 +2816,6 @@ new_objects:
}
local_irq_save(flags);
if (c->page)
flush_slab(s, c);
/*
* No other reference to the page yet so we can
* muck around with it freely without cmpxchg
@ -2829,14 +2824,12 @@ new_objects:
page->freelist = NULL;
stat(s, ALLOC_SLAB);
c->page = page;
check_new_page:
if (kmem_cache_debug(s)) {
if (!alloc_debug_processing(s, page, freelist, addr)) {
/* Slab failed checks. Next slab needed */
c->page = NULL;
local_irq_restore(flags);
goto new_slab;
} else {
@ -2855,10 +2848,18 @@ check_new_page:
*/
goto return_single;
if (unlikely(c->page))
flush_slab(s, c);
c->page = page;
goto load_freelist;
return_single:
if (unlikely(c->page))
flush_slab(s, c);
c->page = page;
deactivate_slab(s, page, get_freepointer(s, freelist), c);
local_irq_restore(flags);
return freelist;