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linux/kernel/module/Makefile

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module: Move all into module/ No functional changes. This patch moves all module related code into a separate directory, modifies each file name and creates a new Makefile. Note: this effort is in preparation to refactor core module code. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:31 +00:00
# SPDX-License-Identifier: GPL-2.0-only
#
# Makefile for linux kernel module support
#
# These are called from save_stack_trace() on slub debug path,
# and produce insane amounts of uninteresting coverage.
KCOV_INSTRUMENT_module.o := n
module: fold usermode helper kmod into modules directory The kernel/kmod.c is already only built if we enabled modules, so just stuff it under kernel/module/kmod.c and unify the MAINTAINERS file for it. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-19 21:35:42 +00:00
obj-y += main.o
obj-y += strict_rwx.o
obj-y += kmod.o
module: add debugging auto-load duplicate module support The finit_module() system call can in the worst case use up to more than twice of a module's size in virtual memory. Duplicate finit_module() system calls are non fatal, however they unnecessarily strain virtual memory during bootup and in the worst case can cause a system to fail to boot. This is only known to currently be an issue on systems with larger number of CPUs. To help debug this situation we need to consider the different sources for finit_module(). Requests from the kernel that rely on module auto-loading, ie, the kernel's *request_module() API, are one source of calls. Although modprobe checks to see if a module is already loaded prior to calling finit_module() there is a small race possible allowing userspace to trigger multiple modprobe calls racing against modprobe and this not seeing the module yet loaded. This adds debugging support to the kernel module auto-loader (*request_module() calls) to easily detect duplicate module requests. To aid with possible bootup failure issues incurred by this, it will converge duplicates requests to a single request. This avoids any possible strain on virtual memory during bootup which could be incurred by duplicate module autoloading requests. Folks debugging virtual memory abuse on bootup can and should enable this to see what pr_warn()s come on, to see if module auto-loading is to blame for their wores. If they see duplicates they can further debug this by enabling the module.enable_dups_trace kernel parameter or by enabling CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS_TRACE. Current evidence seems to point to only a few duplicates for module auto-loading. And so the source for other duplicates creating heavy virtual memory pressure due to larger number of CPUs should becoming from another place (likely udev). Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-04-14 05:28:39 +00:00
obj-$(CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS) += dups.o
module: Move all into module/ No functional changes. This patch moves all module related code into a separate directory, modifies each file name and creates a new Makefile. Note: this effort is in preparation to refactor core module code. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:31 +00:00
obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
obj-$(CONFIG_MODULE_SIG) += signing.o
module: Move livepatch support to a separate file No functional change. This patch migrates livepatch support (i.e. used during module add/or load and remove/or deletion) from core module code into kernel/module/livepatch.c. At the moment it contains code to persist Elf information about a given livepatch module, only. The new file was added to MAINTAINERS. Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:34 +00:00
obj-$(CONFIG_LIVEPATCH) += livepatch.o
module: Move latched RB-tree support to a separate file No functional change. This patch migrates module latched RB-tree support (e.g. see __module_address()) from core module code into kernel/module/tree_lookup.c. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:35 +00:00
obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o
module: Move kmemleak support to a separate file No functional change. This patch migrates kmemleak code out of core module code into kernel/module/debug_kmemleak.c Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:38 +00:00
obj-$(CONFIG_DEBUG_KMEMLEAK) += debug_kmemleak.o
module: Move kallsyms support into a separate file No functional change. This patch migrates kallsyms code out of core module code kernel/module/kallsyms.c Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:39 +00:00
obj-$(CONFIG_KALLSYMS) += kallsyms.o
module: Move procfs support into a separate file No functional change. This patch migrates code that allows one to generate a list of loaded/or linked modules via /proc when procfs support is enabled into kernel/module/procfs.c. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:41 +00:00
obj-$(CONFIG_PROC_FS) += procfs.o
module: Move sysfs support into a separate file No functional change. This patch migrates module sysfs support out of core code into kernel/module/sysfs.c. In addition simple code refactoring to make this possible. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:42 +00:00
obj-$(CONFIG_SYSFS) += sysfs.o
module: Move kdb module related code out of main kdb code No functional change. This patch migrates the kdb 'lsmod' command support out of main kdb code into its own file under kernel/module. In addition to the above, a minor style warning i.e. missing a blank line after declarations, was resolved too. The new file was added to MAINTAINERS. Finally we remove linux/module.h as it is entirely redundant. Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:43 +00:00
obj-$(CONFIG_KGDB_KDB) += kdb.o
module: Move version support into a separate file No functional change. This patch migrates module version support out of core code into kernel/module/version.c. In addition simple code refactoring to make this possible. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-22 14:03:44 +00:00
obj-$(CONFIG_MODVERSIONS) += version.o
module: Introduce module unload taint tracking Currently, only the initial module that tainted the kernel is recorded e.g. when an out-of-tree module is loaded. The purpose of this patch is to allow the kernel to maintain a record of each unloaded module that taints the kernel. So, in addition to displaying a list of linked modules (see print_modules()) e.g. in the event of a detected bad page, unloaded modules that carried a taint/or taints are displayed too. A tainted module unload count is maintained. The number of tracked modules is not fixed. This feature is disabled by default. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-02 20:52:52 +00:00
obj-$(CONFIG_MODULE_UNLOAD_TAINT_TRACKING) += tracking.o
module: add debug stats to help identify memory pressure Loading modules with finit_module() can end up using vmalloc(), vmap() and vmalloc() again, for a total of up to 3 separate allocations in the worst case for a single module. We always kernel_read*() the module, that's a vmalloc(). Then vmap() is used for the module decompression, and if so the last read buffer is freed as we use the now decompressed module buffer to stuff data into our copy module. The last allocation is specific to each architectures but pretty much that's generally a series of vmalloc() calls or a variation of vmalloc to handle ELF sections with special permissions. Evaluation with new stress-ng module support [1] with just 100 ops is proving that you can end up using GiBs of data easily even with all care we have in the kernel and userspace today in trying to not load modules which are already loaded. 100 ops seems to resemble the sort of pressure a system with about 400 CPUs can create on module loading. Although issues relating to duplicate module requests due to each CPU inucurring a new module reuest is silly and some of these are being fixed, we currently lack proper tooling to help diagnose easily what happened, when it happened and who likely is to blame -- userspace or kernel module autoloading. Provide an initial set of stats which use debugfs to let us easily scrape post-boot information about failed loads. This sort of information can be used on production worklaods to try to optimize *avoiding* redundant memory pressure using finit_module(). There's a few examples that can be provided: A 255 vCPU system without the next patch in this series applied: Startup finished in 19.143s (kernel) + 7.078s (userspace) = 26.221s graphical.target reached after 6.988s in userspace And 13.58 GiB of virtual memory space lost due to failed module loading: root@big ~ # cat /sys/kernel/debug/modules/stats Mods ever loaded 67 Mods failed on kread 0 Mods failed on decompress 0 Mods failed on becoming 0 Mods failed on load 1411 Total module size 11464704 Total mod text size 4194304 Failed kread bytes 0 Failed decompress bytes 0 Failed becoming bytes 0 Failed kmod bytes 14588526272 Virtual mem wasted bytes 14588526272 Average mod size 171115 Average mod text size 62602 Average fail load bytes 10339140 Duplicate failed modules: module-name How-many-times Reason kvm_intel 249 Load kvm 249 Load irqbypass 8 Load crct10dif_pclmul 128 Load ghash_clmulni_intel 27 Load sha512_ssse3 50 Load sha512_generic 200 Load aesni_intel 249 Load crypto_simd 41 Load cryptd 131 Load evdev 2 Load serio_raw 1 Load virtio_pci 3 Load nvme 3 Load nvme_core 3 Load virtio_pci_legacy_dev 3 Load virtio_pci_modern_dev 3 Load t10_pi 3 Load virtio 3 Load crc32_pclmul 6 Load crc64_rocksoft 3 Load crc32c_intel 40 Load virtio_ring 3 Load crc64 3 Load The following screen shot, of a simple 8vcpu 8 GiB KVM guest with the next patch in this series applied, shows 226.53 MiB are wasted in virtual memory allocations which due to duplicate module requests during boot. It also shows an average module memory size of 167.10 KiB and an an average module .text + .init.text size of 61.13 KiB. The end shows all modules which were detected as duplicate requests and whether or not they failed early after just the first kernel_read*() call or late after we've already allocated the private space for the module in layout_and_allocate(). A system with module decompression would reveal more wasted virtual memory space. We should put effort now into identifying the source of these duplicate module requests and trimming these down as much possible. Larger systems will obviously show much more wasted virtual memory allocations. root@kmod ~ # cat /sys/kernel/debug/modules/stats Mods ever loaded 67 Mods failed on kread 0 Mods failed on decompress 0 Mods failed on becoming 83 Mods failed on load 16 Total module size 11464704 Total mod text size 4194304 Failed kread bytes 0 Failed decompress bytes 0 Failed becoming bytes 228959096 Failed kmod bytes 8578080 Virtual mem wasted bytes 237537176 Average mod size 171115 Average mod text size 62602 Avg fail becoming bytes 2758544 Average fail load bytes 536130 Duplicate failed modules: module-name How-many-times Reason kvm_intel 7 Becoming kvm 7 Becoming irqbypass 6 Becoming & Load crct10dif_pclmul 7 Becoming & Load ghash_clmulni_intel 7 Becoming & Load sha512_ssse3 6 Becoming & Load sha512_generic 7 Becoming & Load aesni_intel 7 Becoming crypto_simd 7 Becoming & Load cryptd 3 Becoming & Load evdev 1 Becoming serio_raw 1 Becoming nvme 3 Becoming nvme_core 3 Becoming t10_pi 3 Becoming virtio_pci 3 Becoming crc32_pclmul 6 Becoming & Load crc64_rocksoft 3 Becoming crc32c_intel 3 Becoming virtio_pci_modern_dev 2 Becoming virtio_pci_legacy_dev 1 Becoming crc64 2 Becoming virtio 2 Becoming virtio_ring 2 Becoming [0] https://github.com/ColinIanKing/stress-ng.git [1] echo 0 > /proc/sys/vm/oom_dump_tasks ./stress-ng --module 100 --module-name xfs Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-29 03:03:19 +00:00
obj-$(CONFIG_MODULE_STATS) += stats.o
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