From 8400b91c11db9edeb32979a6e9ef3120c91a8db9 Mon Sep 17 00:00:00 2001 From: Alexander Egorenkov Date: Mon, 14 Nov 2022 11:40:08 +0100 Subject: [PATCH] s390/kexec: fix ipl report address for kdump commit c2337a40e04dde1692b5b0a46ecc59f89aaba8a1 upstream. This commit addresses the following erroneous situation with file-based kdump executed on a system with a valid IPL report. On s390, a kdump kernel, its initrd and IPL report if present are loaded into a special and reserved on boot memory region - crashkernel. When a system crashes and kdump was activated before, the purgatory code is entered first which swaps the crashkernel and [0 - crashkernel size] memory regions. Only after that the kdump kernel is entered. For this reason, the pointer to an IPL report in lowcore must point to the IPL report after the swap and not to the address of the IPL report that was located in crashkernel memory region before the swap. Failing to do so, makes the kdump's decompressor try to read memory from the crashkernel memory region which already contains the production's kernel memory. The situation described above caused spontaneous kdump failures/hangs on systems where the Secure IPL is activated because on such systems an IPL report is always present. In that case kdump's decompressor tried to parse an IPL report which frequently lead to illegal memory accesses because an IPL report contains addresses to various data. Cc: Fixes: 99feaa717e55 ("s390/kexec_file: Create ipl report and pass to next kernel") Reviewed-by: Vasily Gorbik Signed-off-by: Alexander Egorenkov Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/machine_kexec_file.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c index 3459362..c7fd818 100644 --- a/arch/s390/kernel/machine_kexec_file.c +++ b/arch/s390/kernel/machine_kexec_file.c @@ -185,8 +185,6 @@ static int kexec_file_add_ipl_report(struct kimage *image, data->memsz = ALIGN(data->memsz, PAGE_SIZE); buf.mem = data->memsz; - if (image->type == KEXEC_TYPE_CRASH) - buf.mem += crashk_res.start; ptr = (void *)ipl_cert_list_addr; end = ptr + ipl_cert_list_size; @@ -223,6 +221,9 @@ static int kexec_file_add_ipl_report(struct kimage *image, data->kernel_buf + offsetof(struct lowcore, ipl_parmblock_ptr); *lc_ipl_parmblock_ptr = (__u32)buf.mem; + if (image->type == KEXEC_TYPE_CRASH) + buf.mem += crashk_res.start; + ret = kexec_add_buffer(&buf); out: return ret; -- 2.7.4