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authorDave Young <dyoung@redhat.com>2024-03-22 13:15:08 +0800
committerIngo Molnar <mingo@kernel.org>2024-03-22 10:07:45 +0100
commitfc7f27cda843ce294c71767d42b9d8abd015d7cb (patch)
tree0dcbcd20daf620486462a036e3fcee25977f16a5
parentb0f269728ccd1d3cabcb6f3a5b610147d98a5dd6 (diff)
x86/kexec: Do not update E820 kexec table for setup_data
crashkernel reservation failed on a Thinkpad t440s laptop recently. Actually the memblock reservation succeeded, but later insert_resource() failed. Test steps: kexec load -> /* make sure add crashkernel param eg. crashkernel=160M */ kexec reboot -> dmesg|grep "crashkernel reserved"; crashkernel memory range like below reserved successfully: 0x00000000d0000000 - 0x00000000da000000 But no such "Crash kernel" region in /proc/iomem The background story: Currently the E820 code reserves setup_data regions for both the current kernel and the kexec kernel, and it inserts them into the resources list. Before the kexec kernel reboots nobody passes the old setup_data, and kexec only passes fresh SETUP_EFI/SETUP_IMA/SETUP_RNG_SEED if needed. Thus the old setup data memory is not used at all. Due to old kernel updates the kexec e820 table as well so kexec kernel sees them as E820_TYPE_RESERVED_KERN regions, and later the old setup_data regions are inserted into resources list in the kexec kernel by e820__reserve_resources(). Note, due to no setup_data is passed in for those old regions they are not early reserved (by function early_reserve_memory), and the crashkernel memblock reservation will just treat them as usable memory and it could reserve the crashkernel region which overlaps with the old setup_data regions. And just like the bug I noticed here, kdump insert_resource failed because e820__reserve_resources has added the overlapped chunks in /proc/iomem already. Finally, looking at the code, the old setup_data regions are not used at all as no setup_data is passed in by the kexec boot loader. Although something like SETUP_PCI etc could be needed, kexec should pass the info as new setup_data so that kexec kernel can take care of them. This should be taken care of in other separate patches if needed. Thus drop the useless buggy code here. Signed-off-by: Dave Young <dyoung@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Eric DeVolder <eric.devolder@oracle.com> Cc: Baoquan He <bhe@redhat.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: https://lore.kernel.org/r/Zf0T3HCG-790K-pZ@darkstar.users.ipa.redhat.com
-rw-r--r--arch/x86/kernel/e820.c17
1 files changed, 1 insertions, 16 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index b66f540de054..6f1b379e3b38 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1016,17 +1016,6 @@ void __init e820__reserve_setup_data(void)
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
- /*
- * SETUP_EFI, SETUP_IMA and SETUP_RNG_SEED are supplied by
- * kexec and do not need to be reserved.
- */
- if (data->type != SETUP_EFI &&
- data->type != SETUP_IMA &&
- data->type != SETUP_RNG_SEED)
- e820__range_update_kexec(pa_data,
- sizeof(*data) + data->len,
- E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
-
if (data->type == SETUP_INDIRECT) {
len += data->len;
early_memunmap(data, sizeof(*data));
@@ -1038,12 +1027,9 @@ void __init e820__reserve_setup_data(void)
indirect = (struct setup_indirect *)data->data;
- if (indirect->type != SETUP_INDIRECT) {
+ if (indirect->type != SETUP_INDIRECT)
e820__range_update(indirect->addr, indirect->len,
E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
- e820__range_update_kexec(indirect->addr, indirect->len,
- E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
- }
}
pa_data = pa_next;
@@ -1051,7 +1037,6 @@ void __init e820__reserve_setup_data(void)
}
e820__update_table(e820_table);
- e820__update_table(e820_table_kexec);
pr_info("extended physical RAM map:\n");
e820__print_table("reserve setup_data");