5.4-stable review patch. If anyone has any objections, please let me know.
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From: pangliyuan pangliyuan1@huawei.com
[ Upstream commit bdb0ca39e0acccf6771db49c3f94ed787d05f2d7 ]
Clearing slab cache will free all znode in memory and make c->zroot.znode = NULL, then dumping tnc tree will access c->zroot.znode which cause null pointer dereference.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219624#c0 Fixes: 1e51764a3c2a ("UBIFS: add new flash file system") Signed-off-by: pangliyuan pangliyuan1@huawei.com Reviewed-by: Zhihao Cheng chengzhihao1@huawei.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ubifs/debug.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c index 992b74f9c9414..b5efbaf7eac2b 100644 --- a/fs/ubifs/debug.c +++ b/fs/ubifs/debug.c @@ -925,16 +925,20 @@ void ubifs_dump_tnc(struct ubifs_info *c)
pr_err("\n"); pr_err("(pid %d) start dumping TNC tree\n", current->pid); - znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, NULL); - level = znode->level; - pr_err("== Level %d ==\n", level); - while (znode) { - if (level != znode->level) { - level = znode->level; - pr_err("== Level %d ==\n", level); + if (c->zroot.znode) { + znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, NULL); + level = znode->level; + pr_err("== Level %d ==\n", level); + while (znode) { + if (level != znode->level) { + level = znode->level; + pr_err("== Level %d ==\n", level); + } + ubifs_dump_znode(c, znode); + znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, znode); } - ubifs_dump_znode(c, znode); - znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, znode); + } else { + pr_err("empty TNC tree in memory\n"); } pr_err("(pid %d) finish dumping TNC tree\n", current->pid); }