| Message ID | 80b02fbfe6796c85322244f2e3110295787df3a6.1679098721.git.wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs-progs: use alloc_dummy_extent_buffer() for temporaray super block | expand |
On 3/18/23 08:18, Qu Wenruo wrote: > [FALSE ALERT] > There is a false alert when compiling btrfs-progs using gcc 12.2.1: > > $ make D=1 > kernel-shared/print-tree.c: In function 'print_sys_chunk_array': > kernel-shared/print-tree.c:1797:9: warning: 'buf' may be used uninitialized [-Wmaybe-uninitialized] > 1797 | write_extent_buffer(buf, sb, 0, sizeof(*sb)); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > In file included from ./kernel-shared/ctree.h:27, > from kernel-shared/print-tree.c:24: > ./kernel-shared/extent_io.h:148:6: note: by argument 1 of type 'const struct extent_buffer *' to 'write_extent_buffer' declared here > 148 | void write_extent_buffer(const struct extent_buffer *eb, const void *src, > | ^~~~~~~~~~~~~~~~~~~ > > [CAUSE] > This is a false alert, the uninitialized part of buf will not be > utilized at all during write_extent_buffer(). > > [FIX] > Instead of allocating such adhoc buf, go a more formal way by calling > alloc_dummy_extent_buffer(), which would properly setting all the > members. > > Signed-off-by: Qu Wenruo <wqu@suse.com> looks good. Reviewed-by: Anand Jain <anand.jain@oracle.com>
On Sat, Mar 18, 2023 at 08:18:42AM +0800, Qu Wenruo wrote: > [FALSE ALERT] > There is a false alert when compiling btrfs-progs using gcc 12.2.1: > > $ make D=1 > kernel-shared/print-tree.c: In function 'print_sys_chunk_array': > kernel-shared/print-tree.c:1797:9: warning: 'buf' may be used uninitialized [-Wmaybe-uninitialized] > 1797 | write_extent_buffer(buf, sb, 0, sizeof(*sb)); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > In file included from ./kernel-shared/ctree.h:27, > from kernel-shared/print-tree.c:24: > ./kernel-shared/extent_io.h:148:6: note: by argument 1 of type 'const struct extent_buffer *' to 'write_extent_buffer' declared here > 148 | void write_extent_buffer(const struct extent_buffer *eb, const void *src, > | ^~~~~~~~~~~~~~~~~~~ > > [CAUSE] > This is a false alert, the uninitialized part of buf will not be > utilized at all during write_extent_buffer(). > > [FIX] > Instead of allocating such adhoc buf, go a more formal way by calling > alloc_dummy_extent_buffer(), which would properly setting all the > members. > > Signed-off-by: Qu Wenruo <wqu@suse.com> Added to devel, thanks.
diff --git a/kernel-shared/print-tree.c b/kernel-shared/print-tree.c index a57e9a4d7593..3fb6a37c118b 100644 --- a/kernel-shared/print-tree.c +++ b/kernel-shared/print-tree.c @@ -1789,7 +1789,7 @@ static void print_sys_chunk_array(struct btrfs_super_block *sb) struct btrfs_key key; int item; - buf = malloc(sizeof(*buf) + sizeof(*sb)); + buf = alloc_dummy_extent_buffer(NULL, 0, BTRFS_SUPER_INFO_SIZE); if (!buf) { error_msg(ERROR_MSG_MEMORY, NULL); return; @@ -1860,13 +1860,13 @@ static void print_sys_chunk_array(struct btrfs_super_block *sb) } out: - free(buf); + free_extent_buffer(buf); return; out_short_read: error("sys_array too short to read %u bytes at offset %u", len, cur_offset); - free(buf); + free_extent_buffer(buf); } static int empty_backup(struct btrfs_root_backup *backup)
[FALSE ALERT] There is a false alert when compiling btrfs-progs using gcc 12.2.1: $ make D=1 kernel-shared/print-tree.c: In function 'print_sys_chunk_array': kernel-shared/print-tree.c:1797:9: warning: 'buf' may be used uninitialized [-Wmaybe-uninitialized] 1797 | write_extent_buffer(buf, sb, 0, sizeof(*sb)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ./kernel-shared/ctree.h:27, from kernel-shared/print-tree.c:24: ./kernel-shared/extent_io.h:148:6: note: by argument 1 of type 'const struct extent_buffer *' to 'write_extent_buffer' declared here 148 | void write_extent_buffer(const struct extent_buffer *eb, const void *src, | ^~~~~~~~~~~~~~~~~~~ [CAUSE] This is a false alert, the uninitialized part of buf will not be utilized at all during write_extent_buffer(). [FIX] Instead of allocating such adhoc buf, go a more formal way by calling alloc_dummy_extent_buffer(), which would properly setting all the members. Signed-off-by: Qu Wenruo <wqu@suse.com> --- kernel-shared/print-tree.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)