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2022-07-11kunit: flatten kunit_suite*** to kunit_suite** in .kunit_test_suitesDaniel Latypov1-1/+1
We currently store kunit suites in the .kunit_test_suites ELF section as a `struct kunit_suite***` (modulo some `const`s). For every test file, we store a struct kunit_suite** NULL-terminated array. This adds quite a bit of complexity to the test filtering code in the executor. Instead, let's just make the .kunit_test_suites section contain a single giant array of struct kunit_suite pointers, which can then be directly manipulated. This array is not NULL-terminated, and so none of the test filtering code needs to NULL-terminate anything. Tested-by: Maíra Canal <[email protected]> Reviewed-by: Brendan Higgins <[email protected]> Signed-off-by: Daniel Latypov <[email protected]> Co-developed-by: David Gow <[email protected]> Signed-off-by: David Gow <[email protected]> Signed-off-by: Shuah Khan <[email protected]>
2022-07-11kunit: unify module and builtin suite definitionsJeremy Kerr1-0/+5
Currently, KUnit runs built-in tests and tests loaded from modules differently. For built-in tests, the kunit_test_suite{,s}() macro adds a list of suites in the .kunit_test_suites linker section. However, for kernel modules, a module_init() function is used to run the test suites. This causes problems if tests are included in a module which already defines module_init/exit_module functions, as they'll conflict with the kunit-provided ones. This change removes the kunit-defined module inits, and instead parses the kunit tests from their own section in the module. After module init, we call __kunit_test_suites_init() on the contents of that section, which prepares and runs the suite. This essentially unifies the module- and non-module kunit init formats. Tested-by: Maíra Canal <[email protected]> Reviewed-by: Brendan Higgins <[email protected]> Signed-off-by: Jeremy Kerr <[email protected]> Signed-off-by: Daniel Latypov <[email protected]> Signed-off-by: David Gow <[email protected]> Signed-off-by: Shuah Khan <[email protected]>
2022-05-12module.h: simplify MODULE_IMPORT_NSGreg Kroah-Hartman1-2/+1
In commit ca321ec74322 ("module.h: allow #define strings to work with MODULE_IMPORT_NS") I fixed up the MODULE_IMPORT_NS() macro to allow defined strings to work with it. Unfortunatly I did it in a two-stage process, when it could just be done with the __stringify() macro as pointed out by Masahiro Yamada. Clean this up to only be one macro instead of two steps to achieve the same end result. Fixes: ca321ec74322 ("module.h: allow #define strings to work with MODULE_IMPORT_NS") Reported-by: Masahiro Yamada <[email protected]> Cc: Luis Chamberlain <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Matthias Maennich <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]>
2022-04-05module: Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOCChristophe Leroy1-0/+8
Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC to allow architectures to request having modules data in vmalloc area instead of module area. This is required on powerpc book3s/32 in order to set data non executable, because it is not possible to set executability on page basis, this is done per 256 Mbytes segments. The module area has exec right, vmalloc area has noexec. This can also be useful on other powerpc/32 in order to maximize the chance of code being close enough to kernel core to avoid branch trampolines. Cc: Jason Wessel <[email protected]> Acked-by: Daniel Thompson <[email protected]> Cc: Douglas Anderson <[email protected]> Signed-off-by: Christophe Leroy <[email protected]> [mcgrof: rebased in light of kernel/module/kdb.c move] Signed-off-by: Luis Chamberlain <[email protected]>
2022-04-05module: Move extra signature support out of core codeAaron Tomlin1-5/+7
No functional change. This patch migrates additional module signature check code from core module code into kernel/module/signing.c. Reviewed-by: Christophe Leroy <[email protected]> Signed-off-by: Aaron Tomlin <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]>
2022-04-05module: Move livepatch support to a separate fileAaron Tomlin1-6/+3
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 <[email protected]> Tested-by: Petr Mladek <[email protected]> Signed-off-by: Aaron Tomlin <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]>
2022-01-17Merge branch 'modules-next' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull module updates from Luis Chamberlain: "The biggest change here is in-kernel support for module decompression. This change is being made to help support LSMs like LoadPin as otherwise it loses link between the source of kernel module on the disk and binary blob that is being loaded into the kernel. kmod decompression is still done by userspace even with this is done, both because there are no measurable gains in not doing so and as it adds a secondary extra check for validating the module before loading it into the kernel. The rest of the changes are minor, the only other change worth mentionin there is Jessica Yu is now bowing out of maintenance of modules as she's taking a break from work. While there were other changes posted for modules, those have not yet received much review of testing so I'm not yet comfortable in merging any of those changes yet." * 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: module: fix signature check failures when using in-kernel decompression kernel: Fix spelling mistake "compresser" -> "compressor" MAINTAINERS: add mailing lists for kmod and modules module.h: allow #define strings to work with MODULE_IMPORT_NS module: add in-kernel support for decompressing MAINTAINERS: Remove myself as modules maintainer module: Remove outdated comment
2022-01-11module.h: allow #define strings to work with MODULE_IMPORT_NSGreg Kroah-Hartman1-1/+2
The MODULE_IMPORT_NS() macro does not allow defined strings to work properly with it, so add a layer of indirection to allow this to happen. Cc: Luis Chamberlain <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Matthias Maennich <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Reviewed-by: Matthias Maennich <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]>
2021-12-13exit: Rename module_put_and_exit to module_put_and_kthread_exitEric W. Biederman1-3/+3
Update module_put_and_exit to call kthread_exit instead of do_exit. Change the name to reflect this change in functionality. All of the users of module_put_and_exit are causing the current kthread to exit so this change makes it clear what is happening. There is no functional change. Signed-off-by: "Eric W. Biederman" <[email protected]>
2021-07-19printk: Userspace format indexing supportChris Down1-0/+5
We have a number of systems industry-wide that have a subset of their functionality that works as follows: 1. Receive a message from local kmsg, serial console, or netconsole; 2. Apply a set of rules to classify the message; 3. Do something based on this classification (like scheduling a remediation for the machine), rinse, and repeat. As a couple of examples of places we have this implemented just inside Facebook, although this isn't a Facebook-specific problem, we have this inside our netconsole processing (for alarm classification), and as part of our machine health checking. We use these messages to determine fairly important metrics around production health, and it's important that we get them right. While for some kinds of issues we have counters, tracepoints, or metrics with a stable interface which can reliably indicate the issue, in order to react to production issues quickly we need to work with the interface which most kernel developers naturally use when developing: printk. Most production issues come from unexpected phenomena, and as such usually the code in question doesn't have easily usable tracepoints or other counters available for the specific problem being mitigated. We have a number of lines of monitoring defence against problems in production (host metrics, process metrics, service metrics, etc), and where it's not feasible to reliably monitor at another level, this kind of pragmatic netconsole monitoring is essential. As one would expect, monitoring using printk is rather brittle for a number of reasons -- most notably that the message might disappear entirely in a new version of the kernel, or that the message may change in some way that the regex or other classification methods start to silently fail. One factor that makes this even harder is that, under normal operation, many of these messages are never expected to be hit. For example, there may be a rare hardware bug which one wants to detect if it was to ever happen again, but its recurrence is not likely or anticipated. This precludes using something like checking whether the printk in question was printed somewhere fleetwide recently to determine whether the message in question is still present or not, since we don't anticipate that it should be printed anywhere, but still need to monitor for its future presence in the long-term. This class of issue has happened on a number of occasions, causing unhealthy machines with hardware issues to remain in production for longer than ideal. As a recent example, some monitoring around blk_update_request fell out of date and caused semi-broken machines to remain in production for longer than would be desirable. Searching through the codebase to find the message is also extremely fragile, because many of the messages are further constructed beyond their callsite (eg. btrfs_printk and other module-specific wrappers, each with their own functionality). Even if they aren't, guessing the format and formulation of the underlying message based on the aesthetics of the message emitted is not a recipe for success at scale, and our previous issues with fleetwide machine health checking demonstrate as much. This provides a solution to the issue of silently changed or deleted printks: we record pointers to all printk format strings known at compile time into a new .printk_index section, both in vmlinux and modules. At runtime, this can then be iterated by looking at <debugfs>/printk/index/<module>, which emits the following format, both readable by humans and able to be parsed by machines: $ head -1 vmlinux; shuf -n 5 vmlinux # <level[,flags]> filename:line function "format" <5> block/blk-settings.c:661 disk_stack_limits "%s: Warning: Device %s is misaligned\n" <4> kernel/trace/trace.c:8296 trace_create_file "Could not create tracefs '%s' entry\n" <6> arch/x86/kernel/hpet.c:144 _hpet_print_config "hpet: %s(%d):\n" <6> init/do_mounts.c:605 prepare_namespace "Waiting for root device %s...\n" <6> drivers/acpi/osl.c:1410 acpi_no_auto_serialize_setup "ACPI: auto-serialization disabled\n" This mitigates the majority of cases where we have a highly-specific printk which we want to match on, as we can now enumerate and check whether the format changed or the printk callsite disappeared entirely in userspace. This allows us to catch changes to printks we monitor earlier and decide what to do about it before it becomes problematic. There is no additional runtime cost for printk callers or printk itself, and the assembly generated is exactly the same. Signed-off-by: Chris Down <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Sergey Senozhatsky <[email protected]> Cc: John Ogness <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Kees Cook <[email protected]> Reviewed-by: Petr Mladek <[email protected]> Tested-by: Petr Mladek <[email protected]> Reported-by: kernel test robot <[email protected]> Acked-by: Andy Shevchenko <[email protected]> Acked-by: Jessica Yu <[email protected]> # for module.{c,h} Signed-off-by: Petr Mladek <[email protected]> Link: https://lore.kernel.org/r/e42070983637ac5e384f17fbdbe86d19c7b212a5.1623775748.git.chris@chrisdown.name
2021-07-08module: add printk formats to add module build ID to stacktracesStephen Boyd1-1/+8
Let's make kernel stacktraces easier to identify by including the build ID[1] of a module if the stacktrace is printing a symbol from a module. This makes it simpler for developers to locate a kernel module's full debuginfo for a particular stacktrace. Combined with scripts/decode_stracktrace.sh, a developer can download the matching debuginfo from a debuginfod[2] server and find the exact file and line number for the functions plus offsets in a stacktrace that match the module. This is especially useful for pstore crash debugging where the kernel crashes are recorded in something like console-ramoops and the recovery kernel/modules are different or the debuginfo doesn't exist on the device due to space concerns (the debuginfo can be too large for space limited devices). Originally, I put this on the %pS format, but that was quickly rejected given that %pS is used in other places such as ftrace where build IDs aren't meaningful. There was some discussions on the list to put every module build ID into the "Modules linked in:" section of the stacktrace message but that quickly becomes very hard to read once you have more than three or four modules linked in. It also provides too much information when we don't expect each module to be traversed in a stacktrace. Having the build ID for modules that aren't important just makes things messy. Splitting it to multiple lines for each module quickly explodes the number of lines printed in an oops too, possibly wrapping the warning off the console. And finally, trying to stash away each module used in a callstack to provide the ID of each symbol printed is cumbersome and would require changes to each architecture to stash away modules and return their build IDs once unwinding has completed. Instead, we opt for the simpler approach of introducing new printk formats '%pS[R]b' for "pointer symbolic backtrace with module build ID" and '%pBb' for "pointer backtrace with module build ID" and then updating the few places in the architecture layer where the stacktrace is printed to use this new format. Before: Call trace: lkdtm_WARNING+0x28/0x30 [lkdtm] direct_entry+0x16c/0x1b4 [lkdtm] full_proxy_write+0x74/0xa4 vfs_write+0xec/0x2e8 After: Call trace: lkdtm_WARNING+0x28/0x30 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9] direct_entry+0x16c/0x1b4 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9] full_proxy_write+0x74/0xa4 vfs_write+0xec/0x2e8 [[email protected]: fix build with CONFIG_MODULES=n, tweak code layout] [[email protected]: fix build when CONFIG_MODULES is not set] Link: https://lkml.kernel.org/r/[email protected] [[email protected]: make kallsyms_lookup_buildid() static] [[email protected]: fix build error when CONFIG_SYSFS is disabled] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1] Link: https://sourceware.org/elfutils/Debuginfod.html [2] Signed-off-by: Stephen Boyd <[email protected]> Signed-off-by: Bixuan Cui <[email protected]> Signed-off-by: Randy Dunlap <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Evan Green <[email protected]> Cc: Hsin-Yi Wang <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Sergey Senozhatsky <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Rasmus Villemoes <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Dave Young <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Konstantin Khlebnikov <[email protected]> Cc: Sasha Levin <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: Will Deacon <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2021-04-08add support for Clang CFISami Tolvanen1-2/+11
This change adds support for Clang’s forward-edge Control Flow Integrity (CFI) checking. With CONFIG_CFI_CLANG, the compiler injects a runtime check before each indirect function call to ensure the target is a valid function with the correct static type. This restricts possible call targets and makes it more difficult for an attacker to exploit bugs that allow the modification of stored function pointers. For more details, see: https://clang.llvm.org/docs/ControlFlowIntegrity.html Clang requires CONFIG_LTO_CLANG to be enabled with CFI to gain visibility to possible call targets. Kernel modules are supported with Clang’s cross-DSO CFI mode, which allows checking between independently compiled components. With CFI enabled, the compiler injects a __cfi_check() function into the kernel and each module for validating local call targets. For cross-module calls that cannot be validated locally, the compiler calls the global __cfi_slowpath_diag() function, which determines the target module and calls the correct __cfi_check() function. This patch includes a slowpath implementation that uses __module_address() to resolve call targets, and with CONFIG_CFI_CLANG_SHADOW enabled, a shadow map that speeds up module look-ups by ~3x. Clang implements indirect call checking using jump tables and offers two methods of generating them. With canonical jump tables, the compiler renames each address-taken function to <function>.cfi and points the original symbol to a jump table entry, which passes __cfi_check() validation. This isn’t compatible with stand-alone assembly code, which the compiler doesn’t instrument, and would result in indirect calls to assembly code to fail. Therefore, we default to using non-canonical jump tables instead, where the compiler generates a local jump table entry <function>.cfi_jt for each address-taken function, and replaces all references to the function with the address of the jump table entry. Note that because non-canonical jump table addresses are local to each component, they break cross-module function address equality. Specifically, the address of a global function will be different in each module, as it's replaced with the address of a local jump table entry. If this address is passed to a different module, it won’t match the address of the same function taken there. This may break code that relies on comparing addresses passed from other components. CFI checking can be disabled in a function with the __nocfi attribute. Additionally, CFI can be disabled for an entire compilation unit by filtering out CC_FLAGS_CFI. By default, CFI failures result in a kernel panic to stop a potential exploit. CONFIG_CFI_PERMISSIVE enables a permissive mode, where the kernel prints out a rate-limited warning instead, and allows execution to continue. This option is helpful for locating type mismatches, but should only be enabled during development. Signed-off-by: Sami Tolvanen <[email protected]> Reviewed-by: Kees Cook <[email protected]> Tested-by: Nathan Chancellor <[email protected]> Signed-off-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2021-03-17module: remove never implemented MODULE_SUPPORTED_DEVICELeon Romanovsky1-3/+0
MODULE_SUPPORTED_DEVICE was added in pre-git era and never was implemented. We can safely remove it, because the kernel has grown to have many more reliable mechanisms to determine if device is supported or not. Signed-off-by: Leon Romanovsky <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2021-02-08module: remove EXPORT_UNUSED_SYMBOL*Christoph Hellwig1-12/+0
EXPORT_UNUSED_SYMBOL* is not actually used anywhere. Remove the unused functionality as we generally just remove unused code anyway. Reviewed-by: Miroslav Benes <[email protected]> Reviewed-by: Emil Velikov <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2021-02-08module: remove EXPORT_SYMBOL_GPL_FUTUREChristoph Hellwig1-5/+0
As far as I can tell this has never been used at all, and certainly not any time recently. Reviewed-by: Miroslav Benes <[email protected]> Reviewed-by: Emil Velikov <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2021-02-08module: move struct symsearch to module.cChristoph Hellwig1-11/+0
struct symsearch is only used inside of module.h, so move the definition out of module.h. Reviewed-by: Miroslav Benes <[email protected]> Reviewed-by: Emil Velikov <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2021-02-08module: mark module_mutex staticChristoph Hellwig1-2/+0
Except for two lockdep asserts module_mutex is only used in module.c. Remove the two asserts given that the functions they are in are not exported and just called from the module code, and mark module_mutex static. Reviewed-by: Miroslav Benes <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2021-02-08kallsyms: only build {,module_}kallsyms_on_each_symbol when requiredChristoph Hellwig1-12/+4
kallsyms_on_each_symbol and module_kallsyms_on_each_symbol are only used by the livepatching code, so don't build them if livepatching is not enabled. Reviewed-by: Miroslav Benes <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2021-02-08module: use RCU to synchronize find_moduleChristoph Hellwig1-1/+1
Allow for a RCU-sched critical section around find_module, following the lower level find_module_all helper, and switch the two callers outside of module.c to use such a RCU-sched critical section instead of module_mutex. Reviewed-by: Petr Mladek <[email protected]> Acked-by: Miroslav Benes <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-12-17Merge tag 'modules-for-v5.11' of ↵Linus Torvalds1-14/+14
git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux Pull modules updates from Jessica Yu: "Summary of modules changes for the 5.11 merge window: - Fix a race condition between systemd/udev and the module loader. The module loader was sending a uevent before the module was fully initialized (i.e., before its init function has been called). This means udev can start processing the module uevent before the module has finished initializing, and some udev rules expect that the module has initialized already upon receiving the uevent. This resulted in some systemd mount units failing if udev processes the event faster than the module can finish init. This is fixed by delaying the uevent until after the module has called its init routine. - Make the linker array sections for kernel params and module version attributes more robust by switching to use the alignment of the type in question. Namely, linker section arrays will be constructed using the alignment required by the struct (using __alignof__()) as opposed to a specific value such as sizeof(void *) or sizeof(long). This is less likely to cause breakages should the size of the type ever change (Johan Hovold) - Fix module state inconsistency by setting it back to GOING when a module fails to load and is on its way out (Miroslav Benes) - Some comment and code cleanups (Sergey Shtylyov)" * tag 'modules-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: delay kobject uevent until after module init call module: drop semicolon from version macro init: use type alignment for kernel parameters params: clean up module-param macros params: use type alignment for kernel parameters params: drop redundant "unused" attributes module: simplify version-attribute handling module: drop version-attribute alignment module: fix comment style module: add more 'kernel-doc' comments module: fix up 'kernel-doc' comments module: only handle errors with the *switch* statement in module_sig_check() module: avoid *goto*s in module_sig_check() module: merge repetitive strings in module_sig_check() module: set MODULE_STATE_GOING state when a module fails to load
2020-12-07module: drop semicolon from version macroJohan Hovold1-1/+1
Drop the trailing semicolon from the MODULE_VERSION() macro definition which was left when removing the array-of-pointer indirection. Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-11-25module: simplify version-attribute handlingJohan Hovold1-13/+13
Instead of using the array-of-pointers trick to avoid having gcc mess up the built-in module-version array stride, specify type alignment when declaring entries to prevent gcc from increasing alignment. This is essentially an alternative (one-line) fix to the problem addressed by commit b4bc842802db ("module: deal with alignment issues in built-in module versions"). gcc can increase the alignment of larger objects with static extent as an optimisation, but this can be suppressed by using the aligned attribute when declaring variables. Note that we have been relying on this behaviour for kernel parameters for 16 years and it indeed hasn't changed since the introduction of the aligned attribute in gcc-3.1. Link: https://lore.kernel.org/lkml/[email protected] Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-11-25module: drop version-attribute alignmentJohan Hovold1-1/+1
Commit 98562ad8cb03 ("module: explicitly align module_version_attribute structure") added an alignment attribute to the struct module_version_attribute type in order to fix an alignment issue on m68k where the structure is 2-byte aligned while MODULE_VERSION() forced the __modver section entries to be 4-byte aligned (sizeof(void *)). This was essentially an alternative fix to the problem addressed by b4bc842802db ("module: deal with alignment issues in built-in module versions") which used the array-of-pointer trick to prevent gcc from increasing alignment of the version attribute entries. And with the pointer indirection in place there's no need to increase the alignment of the type. Link: https://lore.kernel.org/lkml/[email protected] Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-11-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski1-0/+4
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-11-14 1) Add BTF generation for kernel modules and extend BTF infra in kernel e.g. support for split BTF loading and validation, from Andrii Nakryiko. 2) Support for pointers beyond pkt_end to recognize LLVM generated patterns on inlined branch conditions, from Alexei Starovoitov. 3) Implements bpf_local_storage for task_struct for BPF LSM, from KP Singh. 4) Enable FENTRY/FEXIT/RAW_TP tracing program to use the bpf_sk_storage infra, from Martin KaFai Lau. 5) Add XDP bulk APIs that introduce a defer/flush mechanism to optimize the XDP_REDIRECT path, from Lorenzo Bianconi. 6) Fix a potential (although rather theoretical) deadlock of hashtab in NMI context, from Song Liu. 7) Fixes for cross and out-of-tree build of bpftool and runqslower allowing build for different target archs on same source tree, from Jean-Philippe Brucker. 8) Fix error path in htab_map_alloc() triggered from syzbot, from Eric Dumazet. 9) Move functionality from test_tcpbpf_user into the test_progs framework so it can run in BPF CI, from Alexander Duyck. 10) Lift hashtab key_size limit to be larger than MAX_BPF_STACK, from Florian Lehner. Note that for the fix from Song we have seen a sparse report on context imbalance which requires changes in sparse itself for proper annotation detection where this is currently being discussed on linux-sparse among developers [0]. Once we have more clarification/guidance after their fix, Song will follow-up. [0] https://lore.kernel.org/linux-sparse/CAHk-=wh4bx8A8dHnX612MsDO13st6uzAz1mJ1PaHHVevJx_ZCw@mail.gmail.com/T/ https://lore.kernel.org/linux-sparse/[email protected]/T/ * git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (66 commits) net: mlx5: Add xdp tx return bulking support net: mvpp2: Add xdp tx return bulking support net: mvneta: Add xdp tx return bulking support net: page_pool: Add bulk support for ptr_ring net: xdp: Introduce bulking for xdp tx return path bpf: Expose bpf_d_path helper to sleepable LSM hooks bpf: Augment the set of sleepable LSM hooks bpf: selftest: Use bpf_sk_storage in FENTRY/FEXIT/RAW_TP bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP bpf: Rename some functions in bpf_sk_storage bpf: Folding omem_charge() into sk_storage_charge() selftests/bpf: Add asm tests for pkt vs pkt_end comparison. selftests/bpf: Add skb_pkt_end test bpf: Support for pointers beyond pkt_end. tools/bpf: Always run the *-clean recipes tools/bpf: Add bootstrap/ to .gitignore bpf: Fix NULL dereference in bpf_task_storage tools/bpftool: Fix build slowdown tools/runqslower: Build bpftool using HOSTCC tools/runqslower: Enable out-of-tree build ... ==================== Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
2020-11-10bpf: Load and verify kernel module BTFsAndrii Nakryiko1-0/+4
Add kernel module listener that will load/validate and unload module BTF. Module BTFs gets ID generated for them, which makes it possible to iterate them with existing BTF iteration API. They are given their respective module's names, which will get reported through GET_OBJ_INFO API. They are also marked as in-kernel BTFs for tooling to distinguish them from user-provided BTFs. Also, similarly to vmlinux BTF, kernel module BTFs are exposed through sysfs as /sys/kernel/btf/<module-name>. This is convenient for user-space tools to inspect module BTF contents and dump their types with existing tools: [vmuser@archvm bpf]$ ls -la /sys/kernel/btf total 0 drwxr-xr-x 2 root root 0 Nov 4 19:46 . drwxr-xr-x 13 root root 0 Nov 4 19:46 .. ... -r--r--r-- 1 root root 888 Nov 4 19:46 irqbypass -r--r--r-- 1 root root 100225 Nov 4 19:46 kvm -r--r--r-- 1 root root 35401 Nov 4 19:46 kvm_intel -r--r--r-- 1 root root 120 Nov 4 19:46 pcspkr -r--r--r-- 1 root root 399 Nov 4 19:46 serio_raw -r--r--r-- 1 root root 4094095 Nov 4 19:46 vmlinux Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Reviewed-by: Greg Kroah-Hartman <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-10-28module: use hidden visibility for weak symbol referencesArd Biesheuvel1-1/+1
Geert reports that commit be2881824ae9eb92 ("arm64/build: Assert for unwanted sections") results in build errors on arm64 for configurations that have CONFIG_MODULES disabled. The commit in question added ASSERT()s to the arm64 linker script to ensure that linker generated sections such as .got.plt etc are empty, but as it turns out, there are corner cases where the linker does emit content into those sections. More specifically, weak references to function symbols (which can remain unsatisfied, and can therefore not be emitted as relative references) will be emitted as GOT and PLT entries when linking the kernel in PIE mode (which is the case when CONFIG_RELOCATABLE is enabled, which is on by default). What happens is that code such as struct device *(*fn)(struct device *dev); struct device *iommu_device; fn = symbol_get(mdev_get_iommu_device); if (fn) { iommu_device = fn(dev); essentially gets converted into the following when CONFIG_MODULES is off: struct device *iommu_device; if (&mdev_get_iommu_device) { iommu_device = mdev_get_iommu_device(dev); where mdev_get_iommu_device is emitted as a weak symbol reference into the object file. The first reference is decorated with an ordinary ABS64 data relocation (which yields 0x0 if the reference remains unsatisfied). However, the indirect call is turned into a direct call covered by a R_AARCH64_CALL26 relocation, which is converted into a call via a PLT entry taking the target address from the associated GOT entry. Given that such GOT and PLT entries are unnecessary for fully linked binaries such as the kernel, let's give these weak symbol references hidden visibility, so that the linker knows that the weak reference via R_AARCH64_CALL26 can simply remain unsatisfied. Signed-off-by: Ard Biesheuvel <[email protected]> Tested-by: Geert Uytterhoeven <[email protected]> Reviewed-by: Fangrui Song <[email protected]> Acked-by: Jessica Yu <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Kees Cook <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Nick Desaulniers <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
2020-10-25treewide: Convert macro and uses of __section(foo) to __section("foo")Joe Perches1-1/+1
Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/[email protected]/2-convert_section.pl Signed-off-by: Joe Perches <[email protected]> Reviewed-by: Nick Desaulniers <[email protected]> Reviewed-by: Miguel Ojeda <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2020-09-01static_call: Add inline static call infrastructureJosh Poimboeuf1-0/+5
Add infrastructure for an arch-specific CONFIG_HAVE_STATIC_CALL_INLINE option, which is a faster version of CONFIG_HAVE_STATIC_CALL. At runtime, the static call sites are patched directly, rather than using the out-of-line trampolines. Compared to out-of-line static calls, the performance benefits are more modest, but still measurable. Steven Rostedt did some tracepoint measurements: https://lkml.kernel.org/r/[email protected] This code is heavily inspired by the jump label code (aka "static jumps"), as some of the concepts are very similar. For more details, see the comments in include/linux/static_call.h. [peterz: simplified interface; merged trampolines] Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Cc: Linus Torvalds <[email protected]> Link: https://lore.kernel.org/r/[email protected]
2020-08-05modules: inherit TAINT_PROPRIETARY_MODULEChristoph Hellwig1-0/+1
If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag for all modules importing these symbols, and don't allow loading symbols from TAINT_PROPRIETARY_MODULE modules if the module previously imported gplonly symbols. Add a anti-circumvention devices so people don't accidentally get themselves into trouble this way. Comment from Greg: "Ah, the proven-to-be-illegal "GPL Condom" defense :)" [jeyu: pr_info -> pr_err and pr_warn as per discussion] Link: http://lore.kernel.org/r/[email protected] Acked-by: Daniel Vetter <[email protected]> Reviewed-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-08-01modules: return licensing information from find_symbolChristoph Hellwig1-1/+1
Report the GPLONLY status through a new argument. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-08-01modules: rename the licence field in struct symsearch to licenseChristoph Hellwig1-1/+1
Use the same spelling variant as the rest of the file. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-08-01modules: mark each_symbol_section staticChristoph Hellwig1-9/+0
each_symbol_section is only used inside of module.c. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-08-01modules: mark find_symbol staticChristoph Hellwig1-11/+0
find_symbol is only used in module.c. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-08-01modules: mark ref_module staticChristoph Hellwig1-1/+0
ref_module isn't used anywhere outside of module.c. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-06-04Merge branch 'for-linus' of ↵Linus Torvalds1-8/+0
git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching Pull livepatching updates from Jiri Kosina: - simplifications and improvements for issues Peter Ziljstra found during his previous work on W^X cleanups. This allows us to remove livepatch arch-specific .klp.arch sections and add proper support for jump labels in patched code. Also, this patchset removes the last module_disable_ro() usage in the tree. Patches from Josh Poimboeuf and Peter Zijlstra - a few other minor cleanups * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching: MAINTAINERS: add lib/livepatch to LIVE PATCHING livepatch: add arch-specific headers to MAINTAINERS livepatch: Make klp_apply_object_relocs static MAINTAINERS: adjust to livepatch .klp.arch removal module: Make module_enable_ro() static again x86/module: Use text_mutex in apply_relocate_add() module: Remove module_disable_ro() livepatch: Remove module_disable_ro() usage x86/module: Use text_poke() for late relocations s390/module: Use s390_kernel_write() for late relocations s390: Change s390_kernel_write() return type to match memcpy() livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols livepatch: Remove .klp.arch livepatch: Apply vmlinux-specific KLP relocations early livepatch: Disallow vmlinux.ko
2020-05-19kprobes: Prevent probes in .noinstr.text sectionThomas Gleixner1-0/+2
Instrumentation is forbidden in the .noinstr.text section. Make kprobes respect this. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-05-12kprobes: Support NOKPROBE_SYMBOL() in modulesMasami Hiramatsu1-0/+2
Support NOKPROBE_SYMBOL() in modules. NOKPROBE_SYMBOL() records only symbol address in "_kprobe_blacklist" section in the module. Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-05-12kprobes: Support __kprobes blacklist in modulesMasami Hiramatsu1-0/+4
Support __kprobes attribute for blacklist functions in modules. The __kprobes attribute functions are stored in .kprobes.text section. Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-05-08module: Make module_enable_ro() static againJosh Poimboeuf1-6/+0
Now that module_enable_ro() has no more external users, make it static again. Suggested-by: Jessica Yu <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Acked-by: Jessica Yu <[email protected]> Signed-off-by: Jiri Kosina <[email protected]>
2020-05-08module: Remove module_disable_ro()Josh Poimboeuf1-2/+0
module_disable_ro() has no more users. Remove it. Signed-off-by: Josh Poimboeuf <[email protected]> Acked-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Joe Lawrence <[email protected]> Acked-by: Miroslav Benes <[email protected]> Acked-by: Jessica Yu <[email protected]> Signed-off-by: Jiri Kosina <[email protected]>
2020-02-01Merge tag 'kbuild-v5.6' of ↵Linus Torvalds1-1/+11
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - detect missing include guard in UAPI headers - do not create orphan built-in.a or obj-y objects - generate modules.builtin more simply, and drop tristate.conf - simplify built-in initramfs creation - make linux-headers deb package thinner - optimize the deb package build script - misc cleanups * tag 'kbuild-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits) builddeb: split libc headers deployment out into a function builddeb: split kernel headers deployment out into a function builddeb: remove redundant make for ARCH=um builddeb: avoid invoking sub-shells where possible builddeb: remove redundant $objtree/ builddeb: match temporary directory name to the package name builddeb: remove unneeded files in hdrobjfiles for headers package kbuild: use -S instead of -E for precise cc-option test in Kconfig builddeb: allow selection of .deb compressor kbuild: remove 'Building modules, stage 2.' log kbuild: remove *.tmp file when filechk fails kbuild: remove PYTHON2 variable modpost: assume STT_SPARC_REGISTER is defined gen_initramfs.sh: remove intermediate cpio_list on errors initramfs: refactor the initramfs build rules gen_initramfs.sh: always output cpio even without -o option initramfs: add default_cpio_list, and delete -d option support initramfs: generate dependency list and cpio at the same time initramfs: specify $(src)/gen_initramfs.sh as a prerequisite in Makefile initramfs: make initramfs compression choice non-optional ...
2020-01-31Merge tag 'modules-for-v5.6' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux Pull module updates from Jessica Yu: "Summary of modules changes for the 5.6 merge window: - Add "MS" (SHF_MERGE|SHF_STRINGS) section flags to __ksymtab_strings to indicate to the linker that it can perform string deduplication (i.e., duplicate strings are reduced to a single copy in the string table). This means any repeated namespace string would be merged to just one entry in __ksymtab_strings. - Various code cleanups and small fixes (fix small memleak in error path, improve moduleparam docs, silence rcu warnings, improve error logging)" * tag 'modules-for-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module.h: Annotate mod_kallsyms with __rcu module: avoid setting info->name early in case we can fall back to info->mod->name modsign: print module name along with error message kernel/module: Fix memleak in module_add_modinfo_attrs() export.h: reduce __ksymtab_strings string duplication by using "MS" section flags moduleparam: fix kerneldoc modules: lockdep: Suppress suspicious RCU usage warning
2020-01-23module.h: Annotate mod_kallsyms with __rcuMadhuparna Bhowmik1-1/+1
This patch fixes the following sparse errors: kernel/module.c:3623:9: error: incompatible types in comparison expression kernel/module.c:4060:41: error: incompatible types in comparison expression kernel/module.c:4203:28: error: incompatible types in comparison expression kernel/module.c:4225:41: error: incompatible types in comparison expression Signed-off-by: Madhuparna Bhowmik <[email protected]> Signed-off-by: Jessica Yu <[email protected]>
2020-01-07kbuild: create modules.builtin without Makefile.modbuiltin or tristate.confMasahiro Yamada1-1/+11
Commit bc081dd6e9f6 ("kbuild: generate modules.builtin") added infrastructure to generate modules.builtin, the list of all builtin modules. Basically, it works like this: - Kconfig generates include/config/tristate.conf, the list of tristate CONFIG options with a value in a capital letter. - scripts/Makefile.modbuiltin makes Kbuild descend into directories to collect the information of builtin modules. I am not a big fan of it because Kbuild ends up with traversing the source tree twice. I am not sure how perfectly it should work, but this approach cannot avoid false positives; even if the relevant CONFIG option is tristate, some Makefiles forces obj-m to obj-y. Some examples are: arch/powerpc/platforms/powermac/Makefile: obj-$(CONFIG_NVRAM:m=y) += nvram.o net/ipv6/Makefile: obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o net/netlabel/Makefile: obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o Nobody has complained about (or noticed) it, so it is probably fine to have false positives in modules.builtin. This commit simplifies the implementation. Let's exploit the fact that every module has MODULE_LICENSE(). (modpost shows a warning if MODULE_LICENSE is missing. If so, 0-day bot would already have blocked such a module.) I added MODULE_FILE to <linux/module.h>. When the code is being compiled as builtin, it will be filled with the file path of the module, and collected into modules.builtin.info. Then, scripts/link-vmlinux.sh extracts the list of builtin modules out of it. This new approach fixes the false-positives above, but adds another type of false-positives; non-modular code may have MODULE_LICENSE() by mistake. This is not a big deal, it is just the code is always orphan. We can clean it up if we like. You can see cleanup examples by: $ git log --grep='make.* explicitly non-modular' To sum up, this commits deletes lots of code, but still produces almost equivalent results. Please note it does not increase the vmlinux size at all. As you can see in include/asm-generic/vmlinux.lds.h, the .modinfo section is discarded in the link stage. Signed-off-by: Masahiro Yamada <[email protected]>
2019-12-10Merge tag 'v5.5-rc1' into core/kprobes, to resolve conflictsIngo Molnar1-2/+5
Signed-off-by: Ingo Molnar <[email protected]>
2019-11-27module: Remove set_all_modules_text_*()Peter Zijlstra1-4/+0
Now that there are no users of set_all_modules_text_*() left, remove it. While it appears nds32 uses it, it does not have STRICT_MODULE_RWX and therefore ends up with the NOP stubs. Tested-by: Alexei Starovoitov <[email protected]> Tested-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Alexei Starovoitov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Greentime Hu <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Jessica Yu <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vincent Chen <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2019-11-14export,module: add SPDX GPL-2.0 license identifier to headers with no licenseMasahiro Yamada1-2/+5
Commit b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to files with no license") took care of a lot of files without any license information. These headers were not processed by the tool perhaps because they contain "GPL" in the code. I do not see any license boilerplate in them, so they fall back to GPL version 2 only, which is the project default. Signed-off-by: Masahiro Yamada <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2019-09-27Merge branch 'next-integrity' of ↵Linus Torvalds1-3/+0
git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity Pull integrity updates from Mimi Zohar: "The major feature in this time is IMA support for measuring and appraising appended file signatures. In addition are a couple of bug fixes and code cleanup to use struct_size(). In addition to the PE/COFF and IMA xattr signatures, the kexec kernel image may be signed with an appended signature, using the same scripts/sign-file tool that is used to sign kernel modules. Similarly, the initramfs may contain an appended signature. This contained a lot of refactoring of the existing appended signature verification code, so that IMA could retain the existing framework of calculating the file hash once, storing it in the IMA measurement list and extending the TPM, verifying the file's integrity based on a file hash or signature (eg. xattrs), and adding an audit record containing the file hash, all based on policy. (The IMA support for appended signatures patch set was posted and reviewed 11 times.) The support for appended signature paves the way for adding other signature verification methods, such as fs-verity, based on a single system-wide policy. The file hash used for verifying the signature and the signature, itself, can be included in the IMA measurement list" * 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: ima: ima_api: Use struct_size() in kzalloc() ima: use struct_size() in kzalloc() sefltest/ima: support appended signatures (modsig) ima: Fix use after free in ima_read_modsig() MODSIGN: make new include file self contained ima: fix freeing ongoing ahash_request ima: always return negative code for error ima: Store the measurement again when appraising a modsig ima: Define ima-modsig template ima: Collect modsig ima: Implement support for module-style appended signatures ima: Factor xattr_verify() out of ima_appraise_measurement() ima: Add modsig appraise_type option for module-style appended signatures integrity: Select CONFIG_KEYS instead of depending on it PKCS#7: Introduce pkcs7_get_digest() PKCS#7: Refactor verify_pkcs7_signature() MODSIGN: Export module signature definitions ima: initialize the "template" field with the default template
2019-09-22modules: make MODULE_IMPORT_NS() work even when modular builds are disabledLinus Torvalds1-2/+2
It's an unusual configuration, and was apparently never tested, and not caught in linux-next because of a combination of travels and it making it into the tree too late. The fix is to simply move the #define to outside the CONFIG_MODULE section, since MODULE_INFO() will do the right thing. Cc: Martijn Coenen <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Matthias Maennich <[email protected]> Cc: Jessica Yu <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2019-09-10module: add support for symbol namespaces.Matthias Maennich1-0/+2
The EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL() macros can be used to export a symbol to a specific namespace. There are no _GPL_FUTURE and _UNUSED variants because these are currently unused, and I'm not sure they are necessary. I didn't add EXPORT_SYMBOL_NS() for ASM exports; this patch sets the namespace of ASM exports to NULL by default. In case of relative references, it will be relocatable to NULL. If there's a need, this should be pretty easy to add. A module that wants to use a symbol exported to a namespace must add a MODULE_IMPORT_NS() statement to their module code; otherwise, modpost will complain when building the module, and the kernel module loader will emit an error and fail when loading the module. MODULE_IMPORT_NS() adds a modinfo tag 'import_ns' to the module. That tag can be observed by the modinfo command, modpost and kernel/module.c at the time of loading the module. The ELF symbols are renamed to include the namespace with an asm label; for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes 'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace checking, without having to go through all the effort of parsing ELF and relocation records just to get to the struct kernel_symbols. On x86_64 I saw no difference in binary size (compression), but at runtime this will require a word of memory per export to hold the namespace. An alternative could be to store namespaced symbols in their own section and use a separate 'struct namespaced_kernel_symbol' for that section, at the cost of making the module loader more complex. Co-developed-by: Martijn Coenen <[email protected]> Signed-off-by: Martijn Coenen <[email protected]> Reviewed-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Matthias Maennich <[email protected]> Signed-off-by: Jessica Yu <[email protected]>