kernel/git/stable/linux.git/drivers/s390/char/monwriter.c, branch master

s390/monwriter: Reject buffer reuse with different data length

2026-07-02T14:51:06+00:00

When data buffers are reused, e.g. for interval sample records, the first record determines the data length, and the size of the buffer for user copy. Current monwriter code does not check if the data length was changed for subsequent records, which also would never happen for valid user programs. However, a malicious user could change the data length, resulting in out of bounds user copy to the kernel buffer, and memory corruption. By default, the monwriter misc device is created with root-only permissions, so practical impact is typically low. Fix this by checking for changed data length and rejecting such records. Cc: stable@vger.kernel.org Signed-off-by: Gerald Schaefer Reviewed-by: Christian Borntraeger Signed-off-by: Vasily Gorbik

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

s390: Remove KMSG_COMPONENT macro

2025-11-24T10:45:21+00:00

The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel message catalog" which never made it upstream. Remove the macro in order to get rid of a pointless indirection. Replace all users with the string it defines. In almost all cases this leads to a simple replacement like this: - #define KMSG_COMPONENT "appldata" - #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + #define pr_fmt(fmt) "appldata: " fmt Except for some special cases this is just mechanical/scripted work. Acked-by: Thomas Richter Signed-off-by: Heiko Carstens

s390: Convert MACHINE_IS_[LPAR|VM|KVM], etc, machine_is_[lpar|vm|kvm]()

2025-03-04T16:18:07+00:00

Move machine type detection to the decompressor and use static branches to implement and use machine_is_[lpar|vm|kvm]() instead of a runtime check via MACHINE_IS_[LPAR|VM|KVM]. Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: include linux/io.h instead of asm/io.h

2023-07-03T09:19:40+00:00

Include linux/io.h instead of asm/io.h everywhere. linux/io.h includes asm/io.h, so this shouldn't cause any problems. Instead this might help for some randconfig build errors which were reported due to some undefined io related functions. Also move the changed include so it stays grouped together with other includes from the same directory. For ctcm_mpc.c also remove not needed comments (actually questions). Acked-by: Christian Borntraeger Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/monwriter: Remove power management support

2021-06-18T14:41:20+00:00

Power management support was removed for s390 with commit 394216275c7d ("s390: remove broken hibernate / power management support"). Remove leftover monwriter-related power management code. Acked-by: Heiko Carstens Signed-off-by: Peter Oberparleiter Signed-off-by: Vasily Gorbik

s390/monwriter: do not use stack buffers for hardware data

2018-10-09T09:20:53+00:00

With CONFIG_VMAP_STACK=y the stack is allocated from the vmalloc space. Data structures passed to a hardware or a hypervisor interface that requires V=R can not be allocated on the stack anymore. Use kmalloc to get memory for the appldata_parameter_list and appldata_product_id structures. Reviewed-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky

s390/appldata: pass parameter list pointer to appldata_asm

2018-10-09T09:20:50+00:00

In preparation for CONFIG_VMAP_STACK=y move the allocation of the struct appldata_parameter_list to the caller of appldata_asm(). Reviewed-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky

s390/monwriter: fix gcc 8 stringop-truncation warning

2018-07-02T09:25:03+00:00

The following gcc warning is issued for strncpy which is used to deliberately avoid string NUL-termination. Reuse memcpy to avoid the warning. inlined from 'monwrite_diag' at drivers/s390/char/monwriter.c:64:2: ./include/linux/string.h:246:9: warning: '__builtin_strncpy' output truncated before terminating nul copying 7 bytes from a string of the same length [-Wstringop-truncation] Reviewed-by: Gerald Schaefer Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky