This is a note to let you know that I've just added the patch titled s390/dasd: fix error checks in dasd_copy_pair_store() to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: s390-dasd-fix-error-checks-in-dasd_copy_pair_store.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 8171315fd1d8e164c60f62786d607b7cbd4dfb51 Author: Carlos López <clopez@xxxxxxx> Date: Mon Jul 15 13:24:34 2024 +0200 s390/dasd: fix error checks in dasd_copy_pair_store() [ Upstream commit 8e64d2356cbc800b4cd0e3e614797f76bcf0cdb8 ] dasd_add_busid() can return an error via ERR_PTR() if an allocation fails. However, two callsites in dasd_copy_pair_store() do not check the result, potentially resulting in a NULL pointer dereference. Fix this by checking the result with IS_ERR() and returning the error up the stack. Fixes: a91ff09d39f9b ("s390/dasd: add copy pair setup") Signed-off-by: Carlos López <clopez@xxxxxxx> Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240715112434.2111291-3-sth@xxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c index c4e36650c4264..91522dba9fd98 100644 --- a/drivers/s390/block/dasd_devmap.c +++ b/drivers/s390/block/dasd_devmap.c @@ -2258,13 +2258,19 @@ static ssize_t dasd_copy_pair_store(struct device *dev, /* allocate primary devmap if needed */ prim_devmap = dasd_find_busid(prim_busid); - if (IS_ERR(prim_devmap)) + if (IS_ERR(prim_devmap)) { prim_devmap = dasd_add_busid(prim_busid, DASD_FEATURE_DEFAULT); + if (IS_ERR(prim_devmap)) + return PTR_ERR(prim_devmap); + } /* allocate secondary devmap if needed */ sec_devmap = dasd_find_busid(sec_busid); - if (IS_ERR(sec_devmap)) + if (IS_ERR(sec_devmap)) { sec_devmap = dasd_add_busid(sec_busid, DASD_FEATURE_DEFAULT); + if (IS_ERR(sec_devmap)) + return PTR_ERR(sec_devmap); + } /* setting copy relation is only allowed for offline secondary */ if (sec_devmap->device)