From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit f44e07a8afdd713ddc1a8832c39372fe5dd86895 ]
The size of the TOD programmable field was incorrectly increased from four to eight bytes with commit 1a2c5840acf9 ("s390/dump: cleanup CPU save area handling"). This leads to an elf notes section NT_S390_TODPREG which has a size of eight instead of four bytes in case of kdump, however even worse is that the contents is incorrect: it is supposed to contain only the contents of the TOD programmable field, but in fact contains a mix of the TOD programmable field (32 bit upper bits) and parts of the CPU timer register (lower 32 bits).
Fix this by simply changing the size of the todpreg field within the save area structure. This will implicitly also fix the size of the corresponding elf notes sections.
This also gets rid of this compile time warning:
in function ‘fortify_memcpy_chk’, inlined from ‘save_area_add_regs’ at arch/s390/kernel/crash_dump.c:99:2: ./include/linux/fortify-string.h:413:25: error: call to ‘__read_overflow2_field’ declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror=attribute-warning] 413 | __read_overflow2_field(q_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fixes: 1a2c5840acf9 ("s390/dump: cleanup CPU save area handling") Reviewed-by: Christian Borntraeger borntraeger@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/crash_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c index 376f6b6dfb3c..7fb7d4dc18dc 100644 --- a/arch/s390/kernel/crash_dump.c +++ b/arch/s390/kernel/crash_dump.c @@ -45,7 +45,7 @@ struct save_area { u64 fprs[16]; u32 fpc; u32 prefix; - u64 todpreg; + u32 todpreg; u64 timer; u64 todcmp; u64 vxrs_low[16];