Revert: "dm-verity: restart or panic on an I/O error"

This reverts commit e6a3531dd542cb127c8de32ab1e54a48ae19962b.

The problem that the commit e6a3531dd542cb127c8de32ab1e54a48ae19962b
fixes was reported as a security bug, but Google engineers working on
Android and ChromeOS didn't want to change the default behavior, they
want to get -EIO rather than restarting the system, so I am reverting
that commit.

Note also that calling machine_restart from the I/O handling code is
potentially unsafe (the reboot notifiers may wait for the bio that
triggered the restart), but Android uses the reboot notifiers to store
the reboot reason into the PMU microcontroller, so machine_restart must
be used.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Fixes: e6a3531dd542 ("dm-verity: restart or panic on an I/O error")
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Suggested-by: Will Drewry <wad@chromium.org>

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 36e4ddfe2d158167b8cc50af1405762ed0b120ca..24ba9a10444cff49eacfe65395432afd7796cc1b 100644 (file)
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -273,10 +273,8 @@ out:
        if (v->mode == DM_VERITY_MODE_LOGGING)
                return 0;
 
-       if (v->mode == DM_VERITY_MODE_RESTART) {
-               pr_emerg("dm-verity device corrupted\n");
-               emergency_restart();
-       }
+       if (v->mode == DM_VERITY_MODE_RESTART)
+               kernel_restart("dm-verity device corrupted");
 
        if (v->mode == DM_VERITY_MODE_PANIC)
                panic("dm-verity device corrupted");
@@ -599,23 +597,6 @@ static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
        if (!static_branch_unlikely(&use_bh_wq_enabled) || !io->in_bh)
                verity_fec_finish_io(io);
 
-       if (unlikely(status != BLK_STS_OK) &&
-           unlikely(!(bio->bi_opf & REQ_RAHEAD)) &&
-           !verity_is_system_shutting_down()) {
-               if (v->mode == DM_VERITY_MODE_RESTART ||
-                   v->mode == DM_VERITY_MODE_PANIC)
-                       DMERR_LIMIT("%s has error: %s", v->data_dev->name,
-                                       blk_status_to_str(status));
-
-               if (v->mode == DM_VERITY_MODE_RESTART) {
-                       pr_emerg("dm-verity device corrupted\n");
-                       emergency_restart();
-               }
-
-               if (v->mode == DM_VERITY_MODE_PANIC)
-                       panic("dm-verity device corrupted");
-       }
-
        bio_endio(bio);
 }