alistair23-linux/include/asm-x86/pgalloc_64.h
Ingo Molnar 58d5d0d8dd x86: fix deadlock, make pgd_lock irq-safe
lockdep just caught this one:

=================================
[ INFO: inconsistent lock state ]
2.6.24 #38
---------------------------------
inconsistent {in-softirq-W} -> {softirq-on-W} usage.
swapper/1 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (pgd_lock){-+..}, at: [<ffffffff8022a9ea>] mm_init+0x1da/0x250
{in-softirq-W} state was registered at:
  [<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 394559
hardirqs last  enabled at (394559): [<ffffffff80267f0a>] get_page_from_freelist+0x30a/0x4c0
hardirqs last disabled at (394558): [<ffffffff80267d25>] get_page_from_freelist+0x125/0x4c0
softirqs last  enabled at (393952): [<ffffffff80232f8e>] __do_softirq+0xce/0xe0
softirqs last disabled at (393945): [<ffffffff8020c57c>] call_softirq+0x1c/0x30

other info that might help us debug this:
no locks held by swapper/1.

stack backtrace:
Pid: 1, comm: swapper Not tainted 2.6.24 #38

Call Trace:
 [<ffffffff8024e1fb>] print_usage_bug+0x18b/0x190
 [<ffffffff8024f55d>] mark_lock+0x53d/0x560
 [<ffffffff8024fffa>] __lock_acquire+0x3ca/0xed0
 [<ffffffff80250ba8>] lock_acquire+0xa8/0xe0
 [<ffffffff8022a9ea>] ? mm_init+0x1da/0x250
 [<ffffffff809bcd10>] _spin_lock+0x30/0x70
 [<ffffffff8022a9ea>] mm_init+0x1da/0x250
 [<ffffffff8022aa99>] mm_alloc+0x39/0x50
 [<ffffffff8028b95a>] bprm_mm_init+0x2a/0x1a0
 [<ffffffff8028d12b>] do_execve+0x7b/0x220
 [<ffffffff80209776>] sys_execve+0x46/0x70
 [<ffffffff8020c214>] kernel_execve+0x64/0xd0
 [<ffffffff8020901e>] ? _stext+0x1e/0x20
 [<ffffffff802090ba>] init_post+0x9a/0xf0
 [<ffffffff809bc5f6>] ? trace_hardirqs_on_thunk+0x35/0x3a
 [<ffffffff8024f75a>] ? trace_hardirqs_on+0xba/0xd0
 [<ffffffff8020c1a8>] ? child_rip+0xa/0x12
 [<ffffffff8020bcbc>] ? restore_args+0x0/0x44
 [<ffffffff8020c19e>] ? child_rip+0x0/0x12

turns out that pgd_lock has been used on 64-bit x86 in an irq-unsafe
way for almost two years, since commit 8c914cb704.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-06 22:39:45 +01:00

122 lines
3.1 KiB
C

#ifndef _X86_64_PGALLOC_H
#define _X86_64_PGALLOC_H
#include <asm/pda.h>
#include <linux/threads.h>
#include <linux/mm.h>
#define pmd_populate_kernel(mm, pmd, pte) \
set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte)))
#define pud_populate(mm, pud, pmd) \
set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd)))
#define pgd_populate(mm, pgd, pud) \
set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(pud)))
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *pte)
{
set_pmd(pmd, __pmd(_PAGE_TABLE | (page_to_pfn(pte) << PAGE_SHIFT)));
}
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
free_page((unsigned long)pmd);
}
static inline pmd_t *pmd_alloc_one (struct mm_struct *mm, unsigned long addr)
{
return (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
}
static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
{
return (pud_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
}
static inline void pud_free(struct mm_struct *mm, pud_t *pud)
{
BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
free_page((unsigned long)pud);
}
static inline void pgd_list_add(pgd_t *pgd)
{
struct page *page = virt_to_page(pgd);
unsigned long flags;
spin_lock_irqsave(&pgd_lock, flags);
list_add(&page->lru, &pgd_list);
spin_unlock_irqrestore(&pgd_lock, flags);
}
static inline void pgd_list_del(pgd_t *pgd)
{
struct page *page = virt_to_page(pgd);
unsigned long flags;
spin_lock_irqsave(&pgd_lock, flags);
list_del(&page->lru);
spin_unlock_irqrestore(&pgd_lock, flags);
}
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
unsigned boundary;
pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
if (!pgd)
return NULL;
pgd_list_add(pgd);
/*
* Copy kernel pointers in from init.
* Could keep a freelist or slab cache of those because the kernel
* part never changes.
*/
boundary = pgd_index(__PAGE_OFFSET);
memset(pgd, 0, boundary * sizeof(pgd_t));
memcpy(pgd + boundary,
init_level4_pgt + boundary,
(PTRS_PER_PGD - boundary) * sizeof(pgd_t));
return pgd;
}
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
BUG_ON((unsigned long)pgd & (PAGE_SIZE-1));
pgd_list_del(pgd);
free_page((unsigned long)pgd);
}
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
return (pte_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
}
static inline struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
void *p = (void *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
if (!p)
return NULL;
return virt_to_page(p);
}
/* Should really implement gc for free page table pages. This could be
done with a reference count in struct page. */
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
BUG_ON((unsigned long)pte & (PAGE_SIZE-1));
free_page((unsigned long)pte);
}
static inline void pte_free(struct mm_struct *mm, struct page *pte)
{
__free_page(pte);
}
#define __pte_free_tlb(tlb,pte) tlb_remove_page((tlb),(pte))
#define __pmd_free_tlb(tlb,x) tlb_remove_page((tlb),virt_to_page(x))
#define __pud_free_tlb(tlb,x) tlb_remove_page((tlb),virt_to_page(x))
#endif /* _X86_64_PGALLOC_H */