From: Manfred Spraul <manfred@colorfullife.com>
With the patch applied,
echo "size-4096 0 0 0" > /proc/slabinfo
walks the objects in the size-4096 slab, printing out the calling address
of whoever allocated that object.
It is for leak detection.
DESC
mm/slab.c warning in cache_alloc_debugcheck_after
EDESC
From: Nathan Lynch <nathanl@austin.ibm.com>
From a ppc64 build:
CC mm/slab.o
mm/slab.c: In function `cache_alloc_debugcheck_after':
mm/slab.c:1976: warning: cast from pointer to integer of different size
---
25-akpm/mm/slab.c | 40 ++++++++++++++++++++++++++++++++++++++--
1 files changed, 38 insertions(+), 2 deletions(-)
diff -puN mm/slab.c~slab-leak-detector mm/slab.c
--- 25/mm/slab.c~slab-leak-detector 2004-03-21 00:05:15.178745600 -0800
+++ 25-akpm/mm/slab.c 2004-03-21 00:05:15.185744536 -0800
@@ -1954,6 +1954,15 @@ cache_alloc_debugcheck_after(kmem_cache_
*dbg_redzone1(cachep, objp) = RED_ACTIVE;
*dbg_redzone2(cachep, objp) = RED_ACTIVE;
}
+ {
+ int objnr;
+ struct slab *slabp;
+
+ slabp = GET_PAGE_SLAB(virt_to_page(objp));
+
+ objnr = (objp - slabp->s_mem) / cachep->objsize;
+ slab_bufctl(slabp)[objnr] = (unsigned long)caller;
+ }
objp += obj_dbghead(cachep);
if (cachep->ctor && cachep->flags & SLAB_POISON) {
unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
@@ -2015,12 +2024,14 @@ static void free_block(kmem_cache_t *cac
objnr = (objp - slabp->s_mem) / cachep->objsize;
check_slabp(cachep, slabp);
#if DEBUG
+#if 0
if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
cachep->name, objp);
BUG();
}
#endif
+#endif
slab_bufctl(slabp)[objnr] = slabp->free;
slabp->free = objnr;
STATS_DEC_ACTIVE(cachep);
@@ -2801,6 +2812,29 @@ struct seq_operations slabinfo_op = {
.show = s_show,
};
+static void do_dump_slabp(kmem_cache_t *cachep)
+{
+#if DEBUG
+ struct list_head *q;
+
+ check_irq_on();
+ spin_lock_irq(&cachep->spinlock);
+ list_for_each(q,&cachep->lists.slabs_full) {
+ struct slab *slabp;
+ int i;
+ slabp = list_entry(q, struct slab, list);
+ for (i = 0; i < cachep->num; i++) {
+ unsigned long sym = slab_bufctl(slabp)[i];
+
+ printk("obj %p/%d: %p", slabp, i, (void *)sym);
+ print_symbol(" <%s>", sym);
+ printk("\n");
+ }
+ }
+ spin_unlock_irq(&cachep->spinlock);
+#endif
+}
+
#define MAX_SLABINFO_WRITE 128
/**
* slabinfo_write - Tuning for the slab allocator
@@ -2841,9 +2875,11 @@ ssize_t slabinfo_write(struct file *file
batchcount < 1 ||
batchcount > limit ||
shared < 0) {
- res = -EINVAL;
+ do_dump_slabp(cachep);
+ res = 0;
} else {
- res = do_tune_cpucache(cachep, limit, batchcount, shared);
+ res = do_tune_cpucache(cachep, limit,
+ batchcount, shared);
}
break;
}
_