From: Bob Peterson rpeterso@redhat.com
commit 428f651cb80b227af47fc302e4931791f2fb4741 upstream.
Before this patch, function read_rindex_entry called compute_bitstructs before it allocated a glock for the rgrp. But if compute_bitstructs found a problem with the rgrp, it called gfs2_consist_rgrpd, and that called gfs2_dump_glock for rgd->rd_gl which had not yet been assigned.
read_rindex_entry compute_bitstructs gfs2_consist_rgrpd gfs2_dump_glock <---------rgd->rd_gl was not set.
This patch changes read_rindex_entry so it assigns an rgrp glock before calling compute_bitstructs so gfs2_dump_glock does not reference an unassigned pointer. If an error is discovered, the glock must also be put, so a new goto and label were added.
Reported-by: syzbot+c6fd14145e2f62ca0784@syzkaller.appspotmail.com Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/gfs2/rgrp.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -923,15 +923,15 @@ static int read_rindex_entry(struct gfs2 spin_lock_init(&rgd->rd_rsspin); mutex_init(&rgd->rd_mutex);
- error = compute_bitstructs(rgd); - if (error) - goto fail; - error = gfs2_glock_get(sdp, rgd->rd_addr, &gfs2_rgrp_glops, CREATE, &rgd->rd_gl); if (error) goto fail;
+ error = compute_bitstructs(rgd); + if (error) + goto fail_glock; + rgd->rd_rgl = (struct gfs2_rgrp_lvb *)rgd->rd_gl->gl_lksb.sb_lvbptr; rgd->rd_flags &= ~GFS2_RDF_PREFERRED; if (rgd->rd_data > sdp->sd_max_rg_data) @@ -945,6 +945,7 @@ static int read_rindex_entry(struct gfs2 }
error = 0; /* someone else read in the rgrp; free it and ignore it */ +fail_glock: gfs2_glock_put(rgd->rd_gl);
fail: