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| author | Stephen Boyd <swboyd@chromium.org> | 2021-06-29 04:34:52 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-29 19:53:47 +0200 |
| commit | 792702911f581f7793962fbeb99d5c3a1b28f4c3 (patch) | |
| tree | d5a5a1ba95e9e6c14e3390db40533f99346be378 /lib/vsprintf.c | |
| parent | slub: indicate slab_fix() uses printf formats (diff) | |
| download | linux-792702911f581f7793962fbeb99d5c3a1b28f4c3.tar.xz linux-792702911f581f7793962fbeb99d5c3a1b28f4c3.zip | |
slub: force on no_hash_pointers when slub_debug is enabled
Obscuring the pointers that slub shows when debugging makes for some
confusing slub debug messages:
Padding overwritten. 0x0000000079f0674a-0x000000000d4dce17
Those addresses are hashed for kernel security reasons. If we're trying
to be secure with slub_debug on the commandline we have some big problems
given that we dump whole chunks of kernel memory to the kernel logs.
Let's force on the no_hash_pointers commandline flag when slub_debug is on
the commandline. This makes slub debug messages more meaningful and if by
chance a kernel address is in some slub debug object dump we will have a
better chance of figuring out what went wrong.
Note that we don't use %px in the slub code because we want to reduce the
number of places that %px is used in the kernel. This also nicely prints
a big fat warning at kernel boot if slub_debug is on the commandline so
that we know that this kernel shouldn't be used on production systems.
[akpm@linux-foundation.org: fix build with CONFIG_SLUB_DEBUG=n]
Link: https://lkml.kernel.org/r/20210601182202.3011020-5-swboyd@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Petr Mladek <pmladek@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/vsprintf.c')
| -rw-r--r-- | lib/vsprintf.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index f0c35d9b65bf..cc281f5895f9 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -2186,7 +2186,7 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, bool no_hash_pointers __ro_after_init; EXPORT_SYMBOL_GPL(no_hash_pointers); -static int __init no_hash_pointers_enable(char *str) +int __init no_hash_pointers_enable(char *str) { if (no_hash_pointers) return 0; |