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32fbe524 |
| 25-Mar-2024 |
Baoquan He <bhe@redhat.com> |
crash: use macro to add crashk_res into iomem early for specific arch
There are regression reports[1][2] that crashkernel region on x86_64 can't be added into iomem tree sometime. This causes the l
crash: use macro to add crashk_res into iomem early for specific arch
There are regression reports[1][2] that crashkernel region on x86_64 can't be added into iomem tree sometime. This causes the later failure of kdump loading.
This happened after commit 4a693ce65b18 ("kdump: defer the insertion of crashkernel resources") was merged.
Even though, these reported issues are proved to be related to other component, they are just exposed after above commmit applied, I still would like to keep crashk_res and crashk_low_res being added into iomem early as before because the early adding has been always there on x86_64 and working very well. For safety of kdump, Let's change it back.
Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that only ARCH defining the macro can have the early adding crashk_res/_low_res into iomem. Then define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it.
Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res handling which was mistakenly added back in commit 85fcde402db1 ("kexec: split crashkernel reservation code out from crash_core.c").
[1] [PATCH V2] x86/kexec: do not update E820 kexec table for setup_data https://lore.kernel.org/all/Zfv8iCL6CT2JqLIC@darkstar.users.ipa.redhat.com/T/#u
[2] Question about Address Range Validation in Crash Kernel Allocation https://lore.kernel.org/all/4eeac1f733584855965a2ea62fa4da58@huawei.com/T/#u
Link: https://lkml.kernel.org/r/ZgDYemRQ2jxjLkq+@MiWiFi-R3L-srv Fixes: 4a693ce65b18 ("kdump: defer the insertion of crashkernel resources") Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Huacai Chen <chenhuacai@loongson.cn> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Li Huafei <lihuafei1@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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85fcde40 |
| 24-Jan-2024 |
Baoquan He <bhe@redhat.com> |
kexec: split crashkernel reservation code out from crash_core.c
Patch series "Split crash out from kexec and clean up related config items", v3.
Motivation: ============= Previously, LKP reported a
kexec: split crashkernel reservation code out from crash_core.c
Patch series "Split crash out from kexec and clean up related config items", v3.
Motivation: ============= Previously, LKP reported a building error. When investigating, it can't be resolved reasonablly with the present messy kdump config items.
https://lore.kernel.org/oe-kbuild-all/202312182200.Ka7MzifQ-lkp@intel.com/
The kdump (crash dumping) related config items could causes confusions:
Firstly,
CRASH_CORE enables codes including - crashkernel reservation; - elfcorehdr updating; - vmcoreinfo exporting; - crash hotplug handling;
Now fadump of powerpc, kcore dynamic debugging and kdump all selects CRASH_CORE, while fadump - fadump needs crashkernel parsing, vmcoreinfo exporting, and accessing global variable 'elfcorehdr_addr'; - kcore only needs vmcoreinfo exporting; - kdump needs all of the current kernel/crash_core.c.
So only enabling PROC_CORE or FA_DUMP will enable CRASH_CORE, this mislead people that we enable crash dumping, actual it's not.
Secondly,
It's not reasonable to allow KEXEC_CORE select CRASH_CORE.
Because KEXEC_CORE enables codes which allocate control pages, copy kexec/kdump segments, and prepare for switching. These codes are shared by both kexec reboot and kdump. We could want kexec reboot, but disable kdump. In that case, CRASH_CORE should not be selected.
-------------------- CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_KEXEC=y CONFIG_KEXEC_FILE=y ---------------------
Thirdly,
It's not reasonable to allow CRASH_DUMP select KEXEC_CORE.
That could make KEXEC_CORE, CRASH_DUMP are enabled independently from KEXEC or KEXEC_FILE. However, w/o KEXEC or KEXEC_FILE, the KEXEC_CORE code built in doesn't make any sense because no kernel loading or switching will happen to utilize the KEXEC_CORE code. --------------------- CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y ---------------------
In this case, what is worse, on arch sh and arm, KEXEC relies on MMU, while CRASH_DUMP can still be enabled when !MMU, then compiling error is seen as the lkp test robot reported in above link.
------arch/sh/Kconfig------ config ARCH_SUPPORTS_KEXEC def_bool MMU
config ARCH_SUPPORTS_CRASH_DUMP def_bool BROKEN_ON_SMP ---------------------------
Changes: =========== 1, split out crash_reserve.c from crash_core.c; 2, split out vmcore_infoc. from crash_core.c; 3, move crash related codes in kexec_core.c into crash_core.c; 4, remove dependency of FA_DUMP on CRASH_DUMP; 5, clean up kdump related config items; 6, wrap up crash codes in crash related ifdefs on all 8 arch-es which support crash dumping, except of ppc;
Achievement: =========== With above changes, I can rearrange the config item logic as below (the right item depends on or is selected by the left item):
PROC_KCORE -----------> VMCORE_INFO
|----------> VMCORE_INFO FA_DUMP----| |----------> CRASH_RESERVE
---->VMCORE_INFO / |---->CRASH_RESERVE KEXEC --| /| |--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE KEXEC_FILE --| \ | \---->CRASH_HOTPLUG
KEXEC --| |--> KEXEC_CORE (for kexec reboot only) KEXEC_FILE --|
Test ======== On all 8 architectures, including x86_64, arm64, s390x, sh, arm, mips, riscv, loongarch, I did below three cases of config item setting and building all passed. Take configs on x86_64 as exampmle here:
(1) Both CONFIG_KEXEC and KEXEC_FILE is unset, then all kexec/kdump items are unset automatically: # Kexec and crash features # CONFIG_KEXEC is not set # CONFIG_KEXEC_FILE is not set # end of Kexec and crash features
(2) set CONFIG_KEXEC_FILE and 'make olddefconfig': --------------- # Kexec and crash features CONFIG_CRASH_RESERVE=y CONFIG_VMCORE_INFO=y CONFIG_KEXEC_CORE=y CONFIG_KEXEC_FILE=y CONFIG_CRASH_DUMP=y CONFIG_CRASH_HOTPLUG=y CONFIG_CRASH_MAX_MEMORY_RANGES=8192 # end of Kexec and crash features ---------------
(3) unset CONFIG_CRASH_DUMP in case 2 and execute 'make olddefconfig': ------------------------ # Kexec and crash features CONFIG_KEXEC_CORE=y CONFIG_KEXEC_FILE=y # end of Kexec and crash features ------------------------
Note: For ppc, it needs investigation to make clear how to split out crash code in arch folder. Hope Hari and Pingfan can help have a look, see if it's doable. Now, I make it either have both kexec and crash enabled, or disable both of them altogether.
This patch (of 14):
Both kdump and fa_dump of ppc rely on crashkernel reservation. Move the relevant codes into separate files: crash_reserve.c, include/linux/crash_reserve.h.
And also add config item CRASH_RESERVE to control its enabling of the codes. And update config items which has relationship with crashkernel reservation.
And also change ifdeffery from CONFIG_CRASH_CORE to CONFIG_CRASH_RESERVE when those scopes are only crashkernel reservation related.
And also rename arch/XXX/include/asm/{crash_core.h => crash_reserve.h} on arm64, x86 and risc-v because those architectures' crash_core.h is only related to crashkernel reservation.
[akpm@linux-foundation.org: s/CRASH_RESEERVE/CRASH_RESERVE/, per Klara Modin] Link: https://lkml.kernel.org/r/20240124051254.67105-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20240124051254.67105-2-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Pingfan Liu <piliu@redhat.com> Cc: Klara Modin <klarasmodin@gmail.com> Cc: Michael Kelley <mhklinux@outlook.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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