| Message ID | 1343385254-8299-1-git-send-email-nasastry@in.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 27 Jul 2012 16:04:14 +0530, Nageswara R Sastry wrote: > Check for the return value of 'open_ctree()' before dereferencing it. > > Signed-off-by: Nageswara R Sastry <nasastry@in.ibm.com> > --- > btrfs-image.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/btrfs-image.c b/btrfs-image.c > index f2bbcc8..2a33a55 100644 > --- a/btrfs-image.c > +++ b/btrfs-image.c > @@ -491,6 +491,7 @@ static int create_metadump(const char *input, FILE *out, int num_threads, > int ret; > > root = open_ctree(input, 0, 0); > + BUG_ON(!root); > BUG_ON(root->nodesize != root->leafsize); > > ret = metadump_init(&metadump, root, out, num_threads, > In general, explicit BUG_ON() checks for a NULL pointer are not added to the Linux kernel if the pointer is dereferenced afterwards. When the NULL area is accessed, you get a general protection fault including the call trace and a dump of all registers. Adding explicit BUG_ON(ptr != NULL) adds overhead without bringing any additional information. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 27 Jul 2012 13:09:53 +0200, Stefan Behrens wrote: > On Fri, 27 Jul 2012 16:04:14 +0530, Nageswara R Sastry wrote: >> Check for the return value of 'open_ctree()' before dereferencing it. >> >> Signed-off-by: Nageswara R Sastry <nasastry@in.ibm.com> >> --- >> btrfs-image.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/btrfs-image.c b/btrfs-image.c >> index f2bbcc8..2a33a55 100644 >> --- a/btrfs-image.c >> +++ b/btrfs-image.c >> @@ -491,6 +491,7 @@ static int create_metadump(const char *input, FILE *out, int num_threads, >> int ret; >> >> root = open_ctree(input, 0, 0); >> + BUG_ON(!root); >> BUG_ON(root->nodesize != root->leafsize); >> >> ret = metadump_init(&metadump, root, out, num_threads, >> > > In general, explicit BUG_ON() checks for a NULL pointer are not added to > the Linux kernel if the pointer is dereferenced afterwards. When the > NULL area is accessed, you get a general protection fault including the > call trace and a dump of all registers. Adding explicit BUG_ON(ptr != > NULL) adds overhead without bringing any additional information. Please ignore and excuse my noise from before. Your patch is for btrfs-progs, not for the kernel. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/btrfs-image.c b/btrfs-image.c index f2bbcc8..2a33a55 100644 --- a/btrfs-image.c +++ b/btrfs-image.c @@ -491,6 +491,7 @@ static int create_metadump(const char *input, FILE *out, int num_threads, int ret; root = open_ctree(input, 0, 0); + BUG_ON(!root); BUG_ON(root->nodesize != root->leafsize); ret = metadump_init(&metadump, root, out, num_threads,
Check for the return value of 'open_ctree()' before dereferencing it. Signed-off-by: Nageswara R Sastry <nasastry@in.ibm.com> --- btrfs-image.c | 1 + 1 file changed, 1 insertion(+)