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| author | Jerome Marchand <jmarchan@redhat.com> | 2019-06-12 18:22:26 +0200 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2019-06-25 14:09:13 -0400 |
| commit | a0651926553cfe7992166432e418987760882652 (patch) | |
| tree | 52620aa66ec18fbff33a296bbe83a342a6108f51 | |
| parent | 211ad4b733037f66f9be0a79eade3da7ab11cbb8 (diff) | |
| download | lwn-a0651926553cfe7992166432e418987760882652.tar.gz lwn-a0651926553cfe7992166432e418987760882652.zip | |
dm table: don't copy from a NULL pointer in realloc_argv()
For the first call to realloc_argv() in dm_split_args(), old_argv is
NULL and size is zero. Then memcpy is called, with the NULL old_argv
as the source argument and a zero size argument. AFAIK, this is
undefined behavior and generates the following warning when compiled
with UBSAN on ppc64le:
In file included from ./arch/powerpc/include/asm/paca.h:19,
from ./arch/powerpc/include/asm/current.h:16,
from ./include/linux/sched.h:12,
from ./include/linux/kthread.h:6,
from drivers/md/dm-core.h:12,
from drivers/md/dm-table.c:8:
In function 'memcpy',
inlined from 'realloc_argv' at drivers/md/dm-table.c:565:3,
inlined from 'dm_split_args' at drivers/md/dm-table.c:588:9:
./include/linux/string.h:345:9: error: argument 2 null where non-null expected [-Werror=nonnull]
return __builtin_memcpy(p, q, size);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/md/dm-table.c: In function 'dm_split_args':
./include/linux/string.h:345:9: note: in a call to built-in function '__builtin_memcpy'
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| -rw-r--r-- | drivers/md/dm-table.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 350cf0451456..ec8b27e20de3 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -561,7 +561,7 @@ static char **realloc_argv(unsigned *size, char **old_argv) gfp = GFP_NOIO; } argv = kmalloc_array(new_size, sizeof(*argv), gfp); - if (argv) { + if (argv && old_argv) { memcpy(argv, old_argv, *size * sizeof(*argv)); *size = new_size; } |