lkml.org 
[lkml]   [2017]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] mm/slab: Do not hash pointers when debugging slab
Date
If CONFIG_DEBUG_SLAB/CONFIG_DEBUG_SLAB_LEAK are enabled, the slab code
prints extra debug information when e.g. corruption is detected.
This includes pointers, which are not very useful when hashed.

Fix this by using %px to print unhashed pointers instead where it makes
sense, and by removing the printing of a last user pointer referring to
code.

Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
---
v2:
- Add Acked-by,
- Remove printing of pointer to last user, which refers to code.
---
mm/slab.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 183e996dde5ff37a..4e51ef954026bd15 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1584,11 +1584,8 @@ static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
*dbg_redzone2(cachep, objp));
}

- if (cachep->flags & SLAB_STORE_USER) {
- pr_err("Last user: [<%p>](%pSR)\n",
- *dbg_userword(cachep, objp),
- *dbg_userword(cachep, objp));
- }
+ if (cachep->flags & SLAB_STORE_USER)
+ pr_err("Last user: (%pSR)\n", *dbg_userword(cachep, objp));
realobj = (char *)objp + obj_offset(cachep);
size = cachep->object_size;
for (i = 0; i < size && lines; i += 16, lines--) {
@@ -1621,7 +1618,7 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
/* Mismatch ! */
/* Print header */
if (lines == 0) {
- pr_err("Slab corruption (%s): %s start=%p, len=%d\n",
+ pr_err("Slab corruption (%s): %s start=%px, len=%d\n",
print_tainted(), cachep->name,
realobj, size);
print_objinfo(cachep, objp, 0);
@@ -1650,13 +1647,13 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
if (objnr) {
objp = index_to_obj(cachep, page, objnr - 1);
realobj = (char *)objp + obj_offset(cachep);
- pr_err("Prev obj: start=%p, len=%d\n", realobj, size);
+ pr_err("Prev obj: start=%px, len=%d\n", realobj, size);
print_objinfo(cachep, objp, 2);
}
if (objnr + 1 < cachep->num) {
objp = index_to_obj(cachep, page, objnr + 1);
realobj = (char *)objp + obj_offset(cachep);
- pr_err("Next obj: start=%p, len=%d\n", realobj, size);
+ pr_err("Next obj: start=%px, len=%d\n", realobj, size);
print_objinfo(cachep, objp, 2);
}
}
@@ -2608,7 +2605,7 @@ static void slab_put_obj(struct kmem_cache *cachep,
/* Verify double free bug */
for (i = page->active; i < cachep->num; i++) {
if (get_free_obj(page, i) == objnr) {
- pr_err("slab: double free detected in cache '%s', objp %p\n",
+ pr_err("slab: double free detected in cache '%s', objp %px\n",
cachep->name, objp);
BUG();
}
@@ -2772,7 +2769,7 @@ static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
else
slab_error(cache, "memory outside object was overwritten");

- pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
+ pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
obj, redzone1, redzone2);
}

@@ -3078,7 +3075,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
*dbg_redzone2(cachep, objp) != RED_INACTIVE) {
slab_error(cachep, "double free, or memory outside object was overwritten");
- pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
+ pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
objp, *dbg_redzone1(cachep, objp),
*dbg_redzone2(cachep, objp));
}
@@ -3091,7 +3088,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
cachep->ctor(objp);
if (ARCH_SLAB_MINALIGN &&
((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
- pr_err("0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
+ pr_err("0x%px: not aligned to ARCH_SLAB_MINALIGN=%d\n",
objp, (int)ARCH_SLAB_MINALIGN);
}
return objp;
@@ -4283,7 +4280,7 @@ static void show_symbol(struct seq_file *m, unsigned long address)
return;
}
#endif
- seq_printf(m, "%p", (void *)address);
+ seq_printf(m, "%px", (void *)address);
}

static int leaks_show(struct seq_file *m, void *p)
--
2.7.4
\
 
 \ /
  Last update: 2017-12-13 16:35    [W:0.031 / U:0.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site