user/sven/linux.git/kernel/kexec_core.c, branch v6.13.4

sysctl: treewide: constify the ctl_table argument of proc_handlers

2024-07-24T18:59:29Z

const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh Signed-off-by: Thomas Weißschuh Co-developed-by: Joel Granados Signed-off-by: Joel Granados

kernel misc: Remove the now superfluous sentinel elements from ctl_table array

2024-04-24T07:43:53Z

This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove the sentinel from ctl_table arrays. Reduce by one the values used to compare the size of the adjusted arrays. Signed-off-by: Joel Granados

Merge tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-03-15T01:03:09Z

Pull non-MM updates from Andrew Morton: - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min heap optimizations". - Kuan-Wei Chiu has also sped up the library sorting code in the series "lib/sort: Optimize the number of swaps and comparisons". - Alexey Gladkov has added the ability for code running within an IPC namespace to alter its IPC and MQ limits. The series is "Allow to change ipc/mq sysctls inside ipc namespace". - Geert Uytterhoeven has contributed some dhrystone maintenance work in the series "lib: dhry: miscellaneous cleanups". - Ryusuke Konishi continues nilfs2 maintenance work in the series "nilfs2: eliminate kmap and kmap_atomic calls" "nilfs2: fix kernel bug at submit_bh_wbc()" - Nathan Chancellor has updated our build tools requirements in the series "Bump the minimum supported version of LLVM to 13.0.1". - Muhammad Usama Anjum continues with the selftests maintenance work in the series "selftests/mm: Improve run_vmtests.sh". - Oleg Nesterov has done some maintenance work against the signal code in the series "get_signal: minor cleanups and fix". Plus the usual shower of singleton patches in various parts of the tree. Please see the individual changelogs for details. * tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits) nilfs2: prevent kernel bug at submit_bh_wbc() nilfs2: fix failure to detect DAT corruption in btree and direct mappings ocfs2: enable ocfs2_listxattr for special files ocfs2: remove SLAB_MEM_SPREAD flag usage assoc_array: fix the return value in assoc_array_insert_mid_shortcut() buildid: use kmap_local_page() watchdog/core: remove sysctl handlers from public header nilfs2: use div64_ul() instead of do_div() mul_u64_u64_div_u64: increase precision by conditionally swapping a and b kexec: copy only happens before uchunk goes to zero get_signal: don't initialize ksig->info if SIGNAL_GROUP_EXIT/group_exec_task get_signal: hide_si_addr_tag_bits: fix the usage of uninitialized ksig get_signal: don't abuse ksig->info.si_signo and ksig->sig const_structs.checkpatch: add device_type Normalise "name (ad@dr)" MODULE_AUTHORs to "name " dyndbg: replace kstrdup() + strchr() with kstrdup_and_replace() list: leverage list_is_head() for list_entry_is_head() nilfs2: MAINTAINERS: drop unreachable project mirror site smp: make __smp_processor_id() 0-argument macro fat: fix uninitialized field in nostale filehandles ...

kexec: copy only happens before uchunk goes to zero

2024-03-06T21:07:39Z

When loading segments, ubytes is <= mbytes. When ubytes is exhausted, there could be remaining mbytes. Then in the while loop, the buf pointer advancing with mchunk will causing meaningless reading even though it doesn't harm. So let's change to make sure that all of the copying and the rest only happens before uchunk goes to zero. Link: https://lkml.kernel.org/r/20240222092119.5602-1-gaoshanliukou@163.com Signed-off-by: yang.zhang Acked-by: Baoquan He Signed-off-by: Andrew Morton

crash: split crash dumping code out from kexec_core.c

2024-02-24T01:48:22Z

Currently, KEXEC_CORE select CRASH_CORE automatically because crash codes need be built in to avoid compiling error when building kexec code even though the crash dumping functionality is not enabled. E.g -------------------- CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_KEXEC=y CONFIG_KEXEC_FILE=y --------------------- After splitting out crashkernel reservation code and vmcoreinfo exporting code, there's only crash related code left in kernel/crash_core.c. Now move crash related codes from kexec_core.c to crash_core.c and only build it in when CONFIG_CRASH_DUMP=y. And also wrap up crash codes inside CONFIG_CRASH_DUMP ifdeffery scope, or replace inappropriate CONFIG_KEXEC_CORE ifdef with CONFIG_CRASH_DUMP ifdef in generic kernel files. With these changes, crash_core codes are abstracted from kexec codes and can be disabled at all if only kexec reboot feature is wanted. Link: https://lkml.kernel.org/r/20240124051254.67105-5-bhe@redhat.com Signed-off-by: Baoquan He Cc: Al Viro Cc: Eric W. Biederman Cc: Hari Bathini Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton

kexec: do syscore_shutdown() in kernel_kexec

2024-01-12T23:20:47Z

syscore_shutdown() runs driver and module callbacks to get the system into a state where it can be correctly shut down. In commit 6f389a8f1dd2 ("PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()") syscore_shutdown() was removed from kernel_restart_prepare() and hence got (incorrectly?) removed from the kexec flow. This was innocuous until commit 6735150b6997 ("KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdown") changed the way that KVM registered its shutdown callbacks, switching from reboot notifiers to syscore_ops.shutdown. As syscore_shutdown() is missing from kexec, KVM's shutdown hook is not run and virtualisation is left enabled on the boot CPU which results in triple faults when switching to the new kernel on Intel x86 VT-x with VMXE enabled. Fix this by adding syscore_shutdown() to the kexec sequence. In terms of where to add it, it is being added after migrating the kexec task to the boot CPU, but before APs are shut down. It is not totally clear if this is the best place: in commit 6f389a8f1dd2 ("PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()") it is stated that "syscore_ops operations should be carried with one CPU on-line and interrupts disabled." APs are only offlined later in machine_shutdown(), so this syscore_shutdown() is being run while APs are still online. This seems to be the correct place as it matches where syscore_shutdown() is run in the reboot and halt flows - they also run it before APs are shut down. The assumption is that the commit message in commit 6f389a8f1dd2 ("PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()") is no longer valid. KVM has been discussed here as it is what broke loudly by not having syscore_shutdown() in kexec, but this change impacts more than just KVM; all drivers/modules which register a syscore_ops.shutdown callback will now be invoked in the kexec flow. Looking at some of them like x86 MCE it is probably more correct to also shut these down during kexec. Maintainers of all drivers which use syscore_ops.shutdown are added on CC for visibility. They are: arch/powerpc/platforms/cell/spu_base.c .shutdown = spu_shutdown, arch/x86/kernel/cpu/mce/core.c .shutdown = mce_syscore_shutdown, arch/x86/kernel/i8259.c .shutdown = i8259A_shutdown, drivers/irqchip/irq-i8259.c .shutdown = i8259A_shutdown, drivers/irqchip/irq-sun6i-r.c .shutdown = sun6i_r_intc_shutdown, drivers/leds/trigger/ledtrig-cpu.c .shutdown = ledtrig_cpu_syscore_shutdown, drivers/power/reset/sc27xx-poweroff.c .shutdown = sc27xx_poweroff_shutdown, kernel/irq/generic-chip.c .shutdown = irq_gc_shutdown, virt/kvm/kvm_main.c .shutdown = kvm_shutdown, This has been tested by doing a kexec on x86_64 and aarch64. Link: https://lkml.kernel.org/r/20231213064004.2419447-1-jgowans@amazon.com Fixes: 6735150b6997 ("KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdown") Signed-off-by: James Gowans Cc: Baoquan He Cc: Eric Biederman Cc: Paolo Bonzini Cc: Sean Christopherson Cc: Marc Zyngier Cc: Arnd Bergmann Cc: Tony Luck Cc: Borislav Petkov Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Chen-Yu Tsai Cc: Jernej Skrabec Cc: Samuel Holland Cc: Pavel Machek Cc: Sebastian Reichel Cc: Orson Zhai Cc: Alexander Graf Cc: Jan H. Schoenherr Cc: Signed-off-by: Andrew Morton

kexec_core: fix the assignment to kimage->control_page

2023-12-29T20:22:29Z

image->control_page represents the starting address for allocating the next control page, while hole_end represents the address of the last valid byte of the currently allocated control page. This bug actually does not affect the correctness of allocating control pages, because image->control_page is currently only used in kimage_alloc_crash_control_pages(), and this function, when allocating control pages, will first align image->control_page up to the nearest `(1 << order) << PAGE_SHIFT` boundary, then use this value as the starting address of the next control page. This ensures that the newly allocated control page will use the correct starting address and not overlap with previously allocated control pages. Although it does not affect the correctness of the final result, it is better for us to set image->control_page to the correct value, in case it might be used elsewhere in the future, potentially causing errors. Therefore, after successfully allocating a control page, image->control_page should be updated to `hole_end + 1`, rather than hole_end. Link: https://lkml.kernel.org/r/20231221042308.11076-1-ytcoode@gmail.com Signed-off-by: Yuntao Wang Cc: Baoquan He Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton

kexec: modify the meaning of the end parameter in kimage_is_destination_range()

2023-12-29T20:22:25Z

The end parameter received by kimage_is_destination_range() should be the last valid byte address of the target memory segment plus 1. However, in the locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions, the corresponding value passed to kimage_is_destination_range() is the last valid byte address of the target memory segment, which is 1 less. There are two ways to fix this bug. We can either correct the logic of the locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions, or we can fix kimage_is_destination_range() by making the end parameter represent the last valid byte address of the target memory segment. Here, we choose the second approach. Due to the modification to kimage_is_destination_range(), we also need to adjust its callers, such as kimage_alloc_normal_control_pages() and kimage_alloc_page(). Link: https://lkml.kernel.org/r/20231217033528.303333-2-ytcoode@gmail.com Signed-off-by: Yuntao Wang Acked-by: Baoquan He Cc: Borislav Petkov (AMD) Cc: Dave Hansen Cc: "Eric W. Biederman" Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Thomas Gleixner Signed-off-by: Andrew Morton

kexec: use ALIGN macro instead of open-coding it

2023-12-20T23:02:58Z

Use ALIGN macro instead of open-coding it to improve code readability. Link: https://lkml.kernel.org/r/20231212142706.25149-1-ytcoode@gmail.com Signed-off-by: Yuntao Wang Acked-by: Baoquan He Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton

kexec_file: add kexec_file flag to control debug printing

2023-12-20T23:02:57Z

Patch series "kexec_file: print out debugging message if required", v4. Currently, specifying '-d' on kexec command will print a lot of debugging informationabout kexec/kdump loading with kexec_load interface. However, kexec_file_load prints nothing even though '-d' is specified. It's very inconvenient to debug or analyze the kexec/kdump loading when something wrong happened with kexec/kdump itself or develper want to check the kexec/kdump loading. In this patchset, a kexec_file flag is KEXEC_FILE_DEBUG added and checked in code. If it's passed in, debugging message of kexec_file code will be printed out and can be seen from console and dmesg. Otherwise, the debugging message is printed like beofre when pr_debug() is taken. Note: **** ===== 1) The code in kexec-tools utility also need be changed to support passing KEXEC_FILE_DEBUG to kernel when 'kexec -s -d' is specified. The patch link is here: ========= [PATCH] kexec_file: add kexec_file flag to support debug printing http://lists.infradead.org/pipermail/kexec/2023-November/028505.html 2) s390 also has kexec_file code, while I am not sure what debugging information is necessary. So leave it to s390 developer. Test: **** ==== Testing was done in v1 on x86_64 and arm64. For v4, tested on x86_64 again. And on x86_64, the printed messages look like below: -------------------------------------------------------------- kexec measurement buffer for the loaded kernel at 0x207fffe000. Loaded purgatory at 0x207fff9000 Loaded boot_param, command line and misc at 0x207fff3000 bufsz=0x1180 memsz=0x1180 Loaded 64bit kernel at 0x207c000000 bufsz=0xc88200 memsz=0x3c4a000 Loaded initrd at 0x2079e79000 bufsz=0x2186280 memsz=0x2186280 Final command line is: root=/dev/mapper/fedora_intel--knightslanding--lb--02-root ro rd.lvm.lv=fedora_intel-knightslanding-lb-02/root console=ttyS0,115200N81 crashkernel=256M E820 memmap: 0000000000000000-000000000009a3ff (1) 000000000009a400-000000000009ffff (2) 00000000000e0000-00000000000fffff (2) 0000000000100000-000000006ff83fff (1) 000000006ff84000-000000007ac50fff (2) ...... 000000207fff6150-000000207fff615f (128) 000000207fff6160-000000207fff714f (1) 000000207fff7150-000000207fff715f (128) 000000207fff7160-000000207fff814f (1) 000000207fff8150-000000207fff815f (128) 000000207fff8160-000000207fffffff (1) nr_segments = 5 segment[0]: buf=0x000000004e5ece74 bufsz=0x211 mem=0x207fffe000 memsz=0x1000 segment[1]: buf=0x000000009e871498 bufsz=0x4000 mem=0x207fff9000 memsz=0x5000 segment[2]: buf=0x00000000d879f1fe bufsz=0x1180 mem=0x207fff3000 memsz=0x2000 segment[3]: buf=0x000000001101cd86 bufsz=0xc88200 mem=0x207c000000 memsz=0x3c4a000 segment[4]: buf=0x00000000c6e38ac7 bufsz=0x2186280 mem=0x2079e79000 memsz=0x2187000 kexec_file_load: type:0, start:0x207fff91a0 head:0x109e004002 flags:0x8 --------------------------------------------------------------------------- This patch (of 7): When specifying 'kexec -c -d', kexec_load interface will print loading information, e.g the regions where kernel/initrd/purgatory/cmdline are put, the memmap passed to 2nd kernel taken as system RAM ranges, and printing all contents of struct kexec_segment, etc. These are very helpful for analyzing or positioning what's happening when kexec/kdump itself failed. The debugging printing for kexec_load interface is made in user space utility kexec-tools. Whereas, with kexec_file_load interface, 'kexec -s -d' print nothing. Because kexec_file code is mostly implemented in kernel space, and the debugging printing functionality is missed. It's not convenient when debugging kexec/kdump loading and jumping with kexec_file_load interface. Now add KEXEC_FILE_DEBUG to kexec_file flag to control the debugging message printing. And add global variable kexec_file_dbg_print and macro kexec_dprintk() to facilitate the printing. This is a preparation, later kexec_dprintk() will be used to replace the existing pr_debug(). Once 'kexec -s -d' is specified, it will print out kexec/kdump loading information. If '-d' is not specified, it regresses to pr_debug(). Link: https://lkml.kernel.org/r/20231213055747.61826-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20231213055747.61826-2-bhe@redhat.com Signed-off-by: Baoquan He Cc: Conor Dooley Cc: Joe Perches Cc: Nathan Chancellor Signed-off-by: Andrew Morton