5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefan Haberland <sth@linux.ibm.com>
commit cddb447c62466f3076938ce120028d7b591f9f37 upstream.
dasd_int_handler() completes an NRF read of an unallocated ESE track by
calling ese_read() and unconditionally marking the request
DASD_CQR_SUCCESS. dasd_eckd_ese_read() can return an error before it has
zeroed the destination buffer: a failed sense-data parse or a current
track outside the requested range both return early, leaving the
destination pages untouched. The request is still completed successfully,
so the block layer is handed stale / uninitialized memory instead of
zeros.
Check the ese_read() return value and fail the request through the normal
error path instead of forcing DASD_CQR_SUCCESS.
Fixes: 5e6bdd37c552 ("s390/dasd: fix data corruption for thin provisioned devices")
Cc: <redacted>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://patch.msgid.link/20260805111612.1285190-2-sth@linux.ibm.com (local)
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/s390/block/dasd.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1760,8 +1760,10 @@ void dasd_int_handler(struct ccw_device
return;
}
if (rq_data_dir(req) == READ) {
- device->discipline->ese_read(cqr, irb);
- cqr->status = DASD_CQR_SUCCESS;
+ if (device->discipline->ese_read(cqr, irb))
+ cqr->status = DASD_CQR_ERROR;
+ else
+ cqr->status = DASD_CQR_SUCCESS;
cqr->stopclk = now;
dasd_device_clear_timer(device);
dasd_schedule_device_bh(device);