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mm: Make mem_dump_obj() handle vmalloc() memory

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This commit adds vmalloc() support to mem_dump_obj().  Note that the
vmalloc_dump_obj() function combines the checking and dumping, in
contrast with the split between kmem_valid_obj() and kmem_dump_obj().
The reason for the difference is that the checking in the vmalloc()
case involves acquiring a global lock, and redundant acquisitions of
global locks should be avoided, even on not-so-fast paths.

Note that this change causes on-stack variables to be reported as
vmalloc() storage from kernel_clone() or similar, depending on the degree
of inlining that your compiler does.  This is likely more helpful than
the earlier "non-paged (local) memory".

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <linux-mm@kvack.org>
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2020-12-08 16:13:57 -08:00
parent b70fa3b12f
commit 98f180837a
3 changed files with 26 additions and 6 deletions
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6
include/linux/vmalloc.h
View File

@ -246,4 +246,10 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
int register_vmap_purge_notifier(struct notifier_block *nb);
int unregister_vmap_purge_notifier(struct notifier_block *nb);
#ifdef CONFIG_MMU
bool vmalloc_dump_obj(void *object);
#else
static inline bool vmalloc_dump_obj(void *object) { return false; }
#endif
#endif /* _LINUX_VMALLOC_H */

14
mm/util.c
View File

@ -996,18 +996,20 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
*/
void mem_dump_obj(void *object)
{
if (kmem_valid_obj(object)) {
kmem_dump_obj(object);
return;
}
if (vmalloc_dump_obj(object))
return;
if (!virt_addr_valid(object)) {
if (object == NULL)
pr_cont(" NULL pointer.\n");
else if (object == ZERO_SIZE_PTR)
pr_cont(" zero-size pointer.\n");
else
pr_cont(" non-paged (local) memory.\n");
pr_cont(" non-paged memory.\n");
return;
}
if (kmem_valid_obj(object)) {
kmem_dump_obj(object);
return;
}
pr_cont(" non-slab memory.\n");
pr_cont(" non-slab/vmalloc memory.\n");
}

12
mm/vmalloc.c
View File

@ -3448,6 +3448,18 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
}
#endif /* CONFIG_SMP */
bool vmalloc_dump_obj(void *object)
{
struct vm_struct *vm;
void *objp = (void *)PAGE_ALIGN((unsigned long)object);
vm = find_vm_area(objp);
if (!vm)
return false;
pr_cont(" vmalloc allocated at %pS\n", vm->caller);
return true;
}
#ifdef CONFIG_PROC_FS
static void *s_start(struct seq_file *m, loff_t *pos)
__acquires(&vmap_purge_lock)