Commit ebb3b845 authored Jan 17, 2022 by Bob Peterson Committed by Greg Kroah-Hartman Apr 27, 2022

gfs2: assign rgrp glock before compute_bitstructs



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>

parent 660784e7

fs/gfs2/rgrp.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -925,15 +925,15 @@ static int read_rindex_entry(struct gfs2_inode *ip)
		rgd->rd_bitbytes = be32_to_cpu(buf.ri_bitbytes);
		spin_lock_init(&rgd->rd_rsspin);

		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_UPTODATE \| GFS2_RDF_PREFERRED);
		if (rgd->rd_data > sdp->sd_max_rg_data)
		@@ -950,6 +950,7 @@ static int read_rindex_entry(struct gfs2_inode *ip)
		}

		error = 0; /* someone else read in the rgrp; free it and ignore it */
		fail_glock:
		gfs2_glock_put(rgd->rd_gl);

		fail: