This is a note to let you know that I've just added the patch titled gfs2: Fix kernel NULL pointer dereference in gfs2_rgrp_dump to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: gfs2-fix-kernel-null-pointer-dereference-in-gfs2_rgr.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c05e01171108a0ac853edbe679c364ce54fb0236 Author: Osama Muhammad <osmtendev@xxxxxxxxx> Date: Mon Nov 6 21:21:29 2023 +0500 gfs2: Fix kernel NULL pointer dereference in gfs2_rgrp_dump [ Upstream commit 8877243beafa7c6bfc42022cbfdf9e39b25bd4fa ] Syzkaller has reported a NULL pointer dereference when accessing rgd->rd_rgl in gfs2_rgrp_dump(). This can happen when creating rgd->rd_gl fails in read_rindex_entry(). Add a NULL pointer check in gfs2_rgrp_dump() to prevent that. Reported-and-tested-by: syzbot+da0fc229cc1ff4bb2e6d@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://syzkaller.appspot.com/bug?extid=da0fc229cc1ff4bb2e6d Fixes: 72244b6bc752 ("gfs2: improve debug information when lvb mismatches are found") Signed-off-by: Osama Muhammad <osmtendev@xxxxxxxxx> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 9308190895c8..307b952a41f8 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -2306,7 +2306,7 @@ void gfs2_rgrp_dump(struct seq_file *seq, struct gfs2_rgrpd *rgd, (unsigned long long)rgd->rd_addr, rgd->rd_flags, rgd->rd_free, rgd->rd_free_clone, rgd->rd_dinodes, rgd->rd_requested, rgd->rd_reserved, rgd->rd_extfail_pt); - if (rgd->rd_sbd->sd_args.ar_rgrplvb) { + if (rgd->rd_sbd->sd_args.ar_rgrplvb && rgd->rd_rgl) { struct gfs2_rgrp_lvb *rgl = rgd->rd_rgl; gfs2_print_dbg(seq, "%s L: f:%02x b:%u i:%u\n", fs_id_buf,