From: Jan Höppner <hoeppner@linux.ibm.com> stable inclusion from stable-v4.19.301 commit f75617cc8df4155374132f0b500b0b3ebb967458 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4KR CVE: CVE-2023-52774 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit db46cd1e0426f52999d50fa72cfa97fa39952885 upstream. In dasd_profile_start() the amount of requests on the device queue are counted. The access to the device queue is unprotected against concurrent access. With a lot of parallel I/O, especially with alias devices enabled, the device queue can change while dasd_profile_start() is accessing the queue. In the worst case this leads to a kernel panic due to incorrect pointer accesses. Fix this by taking the device lock before accessing the queue and counting the requests. Additionally the check for a valid profile data pointer can be done earlier to avoid unnecessary locking in a hot path. Cc: <stable@vger.kernel.org> Fixes: 4fa52aa7a82f ("[S390] dasd: add enhanced DASD statistics interface") Reviewed-by: Stefan Haberland <sth@linux.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com> Signed-off-by: Stefan Haberland <sth@linux.ibm.com> Link: https://lore.kernel.org/r/20231025132437.1223363-3-sth@linux.ibm.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- drivers/s390/block/dasd.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 433651225fca..180c24cb4538 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -725,18 +725,20 @@ static void dasd_profile_start(struct dasd_block *block, * we count each request only once. */ device = cqr->startdev; - if (device->profile.data) { - counter = 1; /* request is not yet queued on the start device */ - list_for_each(l, &device->ccw_queue) - if (++counter >= 31) - break; - } + if (!device->profile.data) + return; + + spin_lock(get_ccwdev_lock(device->cdev)); + counter = 1; /* request is not yet queued on the start device */ + list_for_each(l, &device->ccw_queue) + if (++counter >= 31) + break; + spin_unlock(get_ccwdev_lock(device->cdev)); + spin_lock(&device->profile.lock); - if (device->profile.data) { - device->profile.data->dasd_io_nr_req[counter]++; - if (rq_data_dir(req) == READ) - device->profile.data->dasd_read_nr_req[counter]++; - } + device->profile.data->dasd_io_nr_req[counter]++; + if (rq_data_dir(req) == READ) + device->profile.data->dasd_read_nr_req[counter]++; spin_unlock(&device->profile.lock); } -- 2.25.1