On Sun, Jul 23, 2023 at 10:46 PM Su Hui <suhui@xxxxxxxxxxxx> wrote: > > clang warning: fs/ext4/mballoc.c, line 4178, column 6 > Branch condition evaluates to a garbage value. Specifically this is clang's static analysis; not the compiler itself. > > err is uninitialized and will be judged when it enters the > loop first time and the condition "!ext4_sb_block_valid()" > is true. Although this can't make problems now, it's better > to correct it. > > Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx> Hi Su, Thanks for the patch! I see what the warning is getting at; If `len <= 0` then `err` is never initialized, then is used at line 4178 (that is UB). Would you mind sending a v2 with the commit message updated to reflect the above points? I'd be happy to sign-off on that. > --- > fs/ext4/mballoc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 21b903fe546e..769000c970b0 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -4084,7 +4084,7 @@ void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block, > struct ext4_sb_info *sbi = EXT4_SB(sb); > ext4_group_t group; > ext4_grpblk_t blkoff; > - int i, err; > + int i, err = 0; > int already; > unsigned int clen, clen_changed, thisgrp_len; > > -- > 2.30.2 > > -- Thanks, ~Nick Desaulniers
