4.19-stable review patch. If anyone has any objections, please let me know.
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From: ZhaoLong Wang wangzhaolong1@huawei.com
[ Upstream commit a43bdc376deab5fff1ceb93dca55bcab8dbdc1d6 ]
If both ftl.ko and gluebi.ko are loaded, the notifier of ftl triggers NULL pointer dereference when trying to access ‘gluebi->desc’ in gluebi_read().
ubi_gluebi_init ubi_register_volume_notifier ubi_enumerate_volumes ubi_notify_all gluebi_notify nb->notifier_call() gluebi_create mtd_device_register mtd_device_parse_register add_mtd_device blktrans_notify_add not->add() ftl_add_mtd tr->add_mtd() scan_header mtd_read mtd_read_oob mtd_read_oob_std gluebi_read mtd->read() gluebi->desc - NULL
Detailed reproduction information available at the Link [1],
In the normal case, obtain gluebi->desc in the gluebi_get_device(), and access gluebi->desc in the gluebi_read(). However, gluebi_get_device() is not executed in advance in the ftl_add_mtd() process, which leads to NULL pointer dereference.
The solution for the gluebi module is to run jffs2 on the UBI volume without considering working with ftl or mtdblock [2]. Therefore, this problem can be avoided by preventing gluebi from creating the mtdblock device after creating mtd partition of the type MTD_UBIVOLUME.
Fixes: 2ba3d76a1e29 ("UBI: make gluebi a separate module") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217992 [1] Link: https://lore.kernel.org/lkml/441107100.23734.1697904580252.JavaMail.zimbra@n... [2] Signed-off-by: ZhaoLong Wang wangzhaolong1@huawei.com Reviewed-by: Zhihao Cheng chengzhihao1@huawei.com Acked-by: Richard Weinberger richard@nod.at Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com Link: https://lore.kernel.org/linux-mtd/20231220024619.2138625-1-wangzhaolong1@hua... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mtd/mtd_blkdevs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 6a41dfa3c36b..a9aa1b518d81 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -521,7 +521,7 @@ static void blktrans_notify_add(struct mtd_info *mtd) { struct mtd_blktrans_ops *tr;
- if (mtd->type == MTD_ABSENT) + if (mtd->type == MTD_ABSENT || mtd->type == MTD_UBIVOLUME) return;
list_for_each_entry(tr, &blktrans_majors, list) @@ -564,7 +564,7 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr) list_add(&tr->list, &blktrans_majors);
mtd_for_each_device(mtd) - if (mtd->type != MTD_ABSENT) + if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME) tr->add_mtd(tr, mtd);
mutex_unlock(&mtd_table_mutex);