On Sat, Sep 14, 2024 at 11:44:03PM -0700, Daniel Yang wrote: > If exfat_load_upcase_table reaches end and returns -EINVAL, > allocated memory doesn't get freed and while > exfat_load_default_upcase_table allocates more memory, leading to a > memory leak. > > Here's link to syzkaller crash report illustrating this issue: > https://syzkaller.appspot.com/text?tag=CrashReport&x=1406c201980000 > > Signed-off-by: Daniel Yang <danielyangkang@xxxxxxxxx> > Reported-by: syzbot+e1c69cadec0f1a078e3d@xxxxxxxxxxxxxxxxxxxxxxxxx > --- > fs/exfat/nls.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c > index afdf13c34..ec69477d0 100644 > --- a/fs/exfat/nls.c > +++ b/fs/exfat/nls.c > @@ -699,6 +699,7 @@ static int exfat_load_upcase_table(struct super_block *sb, > > exfat_err(sb, "failed to load upcase table (idx : 0x%08x, chksum : 0x%08x, utbl_chksum : 0x%08x)", > index, chksum, utbl_checksum); > + exfat_free_upcase_table(sbi); > return -EINVAL; > } Interesting... How does the mainline manage to avoid the call of exfat_kill_sb(), which should call_rcu() delayed_free(), which calls exfat_free_upcase_table()? Could you verify that your reproducer does *NOT* hit that callchain? AFAICS, the only caller of exfat_load_upcase_table() is exfat_create_upcase_table(), called by __exfat_fill_super(), called by exfat_fill_super(), passed as callback to get_tree_bdev(). And if that's the case, ->kill_sb() should be called on failure and with non-NULL ->s_fs_info... Something odd is going on there.
