kernel.git/drivers/s390, branch linux-6.12.y

s390/cio: Fix device lifecycle handling in css_alloc_subchannel()

2026-03-04T12:19:32Z

[ Upstream commit f65c75b0b9b5a390bc3beadcde0a6fbc3ad118f7 ] `css_alloc_subchannel()` calls `device_initialize()` before setting up the DMA masks. If `dma_set_coherent_mask()` or `dma_set_mask()` fails, the error path frees the subchannel structure directly, bypassing the device model reference counting. Once `device_initialize()` has been called, the embedded struct device must be released via `put_device()`, allowing the release callback to free the container structure. Fix the error path by dropping the initial device reference with `put_device()` instead of calling `kfree()` directly. This ensures correct device lifetime handling and avoids potential use-after-free or double-free issues. Fixes: e5dcf0025d7af ("s390/css: move subchannel lock allocation") Signed-off-by: Salah Triki Reviewed-by: Vineeth Vijayan Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/ap: Fix wrong APQN fill calculation

2026-01-30T09:28:46Z

commit 3317785a8803db629efc759d811d0f589d3a0b2d upstream. The upper limit of the firmware queue fill state for each APQN is reported by the hwinfo.qd field. This field shows the numbers 0-7 for 1-8 queue spaces available. But the exploiting code assumed the real boundary is stored there and thus stoppes queuing in messages one tick too early. Correct the limit calculation and thus offer a boost of 12.5% performance for high traffic on one APQN. Fixes: d4c53ae8e4948 ("s390/ap: store TAPQ hwinfo in struct ap_card") Cc: stable@vger.kernel.org Reported-by: Ingo Franzki Reviewed-by: Ingo Franzki Signed-off-by: Harald Freudenberger Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/dasd: Fix gendisk parent after copy pair swap

2026-01-08T09:14:14Z

commit c943bfc6afb8d0e781b9b7406f36caa8bbf95cb9 upstream. After a copy pair swap the block device's "device" symlink points to the secondary CCW device, but the gendisk's parent remained the primary, leaving /sys/block/ under the wrong parent. Move the gendisk to the secondary's device with device_move(), keeping the sysfs topology consistent after the swap. Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability") Cc: stable@vger.kernel.org #6.1 Reviewed-by: Jan Hoeppner Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/ap: Don't leak debug feature files if AP instructions are not available

2025-12-18T12:54:47Z

[ Upstream commit 020d5dc57874e58d3ebae398f3fe258f029e3d06 ] If no AP instructions are available the AP bus module leaks registered debug feature files. Change function call order to fix this. Fixes: cccd85bfb7bf ("s390/zcrypt: Rework debug feature invocations.") Reviewed-by: Harald Freudenberger Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/ctcm: Fix double-kfree

2025-12-01T10:43:31Z

[ Upstream commit da02a1824884d6c84c5e5b5ac373b0c9e3288ec2 ] The function 'mpc_rcvd_sweep_req(mpcginfo)' is called conditionally from function 'ctcmpc_unpack_skb'. It frees passed mpcginfo. After that a call to function 'kfree' in function 'ctcmpc_unpack_skb' frees it again. Remove 'kfree' call in function 'mpc_rcvd_sweep_req(mpcginfo)'. Bug detected by the clang static analyzer. Fixes: 0c0b20587b9f25a2 ("s390/ctcm: fix potential memory leak") Reviewed-by: Aswin Karuvally Signed-off-by: Aleksei Nikiforov Signed-off-by: Aswin Karuvally Reviewed-by: Simon Horman Link: https://patch.msgid.link/20251112182724.1109474-1-aswin@linux.ibm.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request

2025-10-19T14:33:57Z

commit 8f4ed0ce4857ceb444174503fc9058720d4faaa1 upstream. Currently, if CCW request creation fails with -EINVAL, the DASD driver returns BLK_STS_IOERR to the block layer. This can happen, for example, when a user-space application such as QEMU passes a misaligned buffer, but the original cause of the error is masked as a generic I/O error. This patch changes the behavior so that -EINVAL is returned as BLK_STS_INVAL, allowing user space to properly detect alignment issues instead of interpreting them as I/O errors. Reviewed-by: Stefan Haberland Cc: stable@vger.kernel.org #6.11+ Signed-off-by: Jaehoon Kim Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/dasd: enforce dma_alignment to ensure proper buffer validation

2025-10-19T14:33:57Z

commit 130e6de62107116eba124647116276266be0f84c upstream. The block layer validates buffer alignment using the device's dma_alignment value. If dma_alignment is smaller than logical_block_size(bp_block) -1, misaligned buffer incorrectly pass validation and propagate to the lower-level driver. This patch adjusts dma_alignment to be at least logical_block_size -1, ensuring that misalignment buffers are properly rejected at the block layer and do not reach the DASD driver unnecessarily. Fixes: 2a07bb64d801 ("s390/dasd: Remove DMA alignment") Reviewed-by: Stefan Haberland Cc: stable@vger.kernel.org #6.11+ Signed-off-by: Jaehoon Kim Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/cio: Update purge function to unregister the unused subchannels

2025-10-19T14:33:39Z

[ Upstream commit 9daa5a8795865f9a3c93d8d1066785b07ded6073 ] Starting with 'commit 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")', cio no longer unregisters subchannels when the attached device is invalid or unavailable. As an unintended side-effect, the cio_ignore purge function no longer removes subchannels for devices on the cio_ignore list if no CCW device is attached. This situation occurs when a CCW device is non-operational or unavailable To ensure the same outcome of the purge function as when the current cio_ignore list had been active during boot, update the purge function to remove I/O subchannels without working CCW devices if the associated device number is found on the cio_ignore list. Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers") Suggested-by: Peter Oberparleiter Reviewed-by: Peter Oberparleiter Signed-off-by: Vineeth Vijayan Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/sclp: Fix SCCB present check

2025-08-28T14:31:06Z

commit 430fa71027b6ac9bb0ce5532b8d0676777d4219a upstream. Tracing code called by the SCLP interrupt handler contains early exits if the SCCB address associated with an interrupt is NULL. This check is performed after physical to virtual address translation. If the kernel identity mapping does not start at address zero, the resulting virtual address is never zero, so that the NULL checks won't work. Subsequently this may result in incorrect accesses to the first page of the identity mapping. Fix this by introducing a function that handles the NULL case before address translation. Fixes: ada1da31ce34 ("s390/sclp: sort out physical vs virtual pointers usage") Cc: stable@vger.kernel.org Reviewed-by: Alexander Gordeev Signed-off-by: Peter Oberparleiter Signed-off-by: Alexander Gordeev Signed-off-by: Greg Kroah-Hartman

s390/ap: Unmask SLCF bit in card and queue ap functions sysfs

2025-08-15T10:14:05Z

[ Upstream commit 123b7c7c2ba725daf3bfa5ce421d65b92cb5c075 ] The SLCF bit ("stateless command filtering") introduced with CEX8 cards was because of the function mask's default value suppressed when user space read the ap function for an AP card or queue. Unmask this bit so that user space applications like lszcrypt can evaluate and list this feature. Fixes: d4c53ae8e494 ("s390/ap: store TAPQ hwinfo in struct ap_card") Signed-off-by: Harald Freudenberger Reviewed-by: Holger Dengler Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin