Commit 1e83bc81 authored Apr 07, 2019 by Arnd Bergmann Committed by Theodore Ts'o Apr 07, 2019

ext4: use BUG() instead of BUG_ON(1)



BUG_ON(1) leads to bogus warnings from clang when
CONFIG_PROFILE_ANNOTATED_BRANCHES is set:

 fs/ext4/inode.c:544:4: error: variable 'retval' is used uninitialized whenever 'if' condition is false
      [-Werror,-Wsometimes-uninitialized]
                        BUG_ON(1);
                        ^~~~~~~~~
 include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON'
                                   ^~~~~~~~~~~~~~~~~~~
 include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 fs/ext4/inode.c:591:6: note: uninitialized use occurs here
        if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
            ^~~~~~
 fs/ext4/inode.c:544:4: note: remove the 'if' if its condition is always true
                        BUG_ON(1);
                        ^
 include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON'
                               ^
 fs/ext4/inode.c:502:12: note: initialize the variable 'retval' to silence this warning

Change it to BUG() so clang can see that this code path can never
continue.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>

parent d454a273

fs/ext4/extents_status.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -711,7 +711,7 @@ static void ext4_es_insert_extent_ind_check(struct inode *inode,
		* We don't need to check unwritten extent because
		* indirect-based file doesn't have it.
		*/
		BUG_ON(1);
		BUG();
		}
		} else if (retval == 0) {
		if (ext4_es_is_written(es)) {
		@@ -780,7 +780,7 @@ static int __es_insert_extent(struct inode inode, struct extent_status newes)
		}
		p = &(*p)->rb_right;
		} else {
		BUG_ON(1);
		BUG();
		return -EINVAL;
		}
		}

fs/ext4/inode.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -541,7 +541,7 @@ int ext4_map_blocks(handle_t handle, struct inode inode,
		map->m_len = retval;
		retval = 0;
		} else {
		BUG_ON(1);
		BUG();
		}
		#ifdef ES_AGGRESSIVE_TEST
		ext4_map_blocks_es_recheck(handle, inode, map,
		@@ -1876,7 +1876,7 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
		else if (ext4_es_is_unwritten(&es))
		map->m_flags \|= EXT4_MAP_UNWRITTEN;
		else
		BUG_ON(1);
		BUG();

		#ifdef ES_AGGRESSIVE_TEST
		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);

Admin message