kernel/linux.git/include/asm-generic/vmlinux.lds.h, branch v6.19.11

kbuild: Split .modinfo out from ELF_DETAILS

2026-03-12T11:09:39+00:00

commit 8678591b47469fe16357234efef9b260317b8be4 upstream. Commit 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") added .modinfo to ELF_DETAILS while removing it from COMMON_DISCARDS, as it was needed in vmlinux.unstripped and ELF_DETAILS was present in all architecture specific vmlinux linker scripts. While this shuffle is fine for vmlinux, ELF_DETAILS and COMMON_DISCARDS may be used by other linker scripts, such as the s390 and x86 compressed boot images, which may not expect to have a .modinfo section. In certain circumstances, this could result in a bootloader failing to load the compressed kernel [1]. Commit ddc6cbef3ef1 ("s390/boot/vmlinux.lds.S: Ensure bzImage ends with SecureBoot trailer") recently addressed this for the s390 bzImage but the same bug remains for arm, parisc, and x86. The presence of .modinfo in the x86 bzImage was the root cause of the issue worked around with commit d50f21091358 ("kbuild: align modinfo section for Secureboot Authenticode EDK2 compat"). misc.c in arch/x86/boot/compressed includes lib/decompress_unzstd.c, which in turn includes lib/xxhash.c and its MODULE_LICENSE / MODULE_DESCRIPTION macros due to the STATIC definition. Split .modinfo out from ELF_DETAILS into its own macro and handle it in all vmlinux linker scripts. Discard .modinfo in the places where it was previously being discarded from being in COMMON_DISCARDS, as it has never been necessary in those uses. Cc: stable@vger.kernel.org Fixes: 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") Reported-by: Ed W Closes: https://lore.kernel.org/587f25e0-a80e-46a5-9f01-87cb40cfa377@wildgooses.com/ [1] Tested-by: Ed W # x86_64 Link: https://patch.msgid.link/20260225-separate-modinfo-from-elf-details-v1-1-387ced6baf4b@kernel.org Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

Merge tag 'tracepoints-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-12-05T17:37:41+00:00

Pull unused tracepoints update from Steven Rostedt: "Detect unused tracepoints. If a tracepoint is defined but never used (TRACE_EVENT() created but no trace_() called), it can take up to or more than 5K of memory each. This can add up as there are around a hundred unused tracepoints with various configs. That is 500K of wasted memory. Add a make build parameter of "UT=1" to have the build warn if an unused tracepoint is detected in the build. This allows detection of unused tracepoints to be upstream so that outreachy and the mentoring project can have new developers look for fixing them, without having these warnings suddenly show up when someone upgrades their kernel. When all known unused tracepoints are removed, then the "UT=1" build parameter can be removed and unused tracepoints will always warn. This will catch new unused tracepoints after the current ones have been removed. Summary: - Separate out elf functions from sorttable.c Move out the ELF parsing functions from sorttable.c so that the tracing tooling can use it. - Add a tracepoint verifier tool to the build process If "UT=1" is added to the kernel command line, any unused tracepoints will trigger a warning at build time. - Do not warn about unused tracepoints for tracepoints that are exported There are sever cases where a tracepoint is created by the kernel and used by modules. Since there's no easy way to detect if these are truly unused since the users are in modules, if a tracepoint is exported, assume it will eventually be used by a module. Note, there's not many exported tracepoints so this should not be a problem to ignore them. - Have building of modules also detect unused tracepoints Do not only check the main vmlinux for unused tracepoints, also check modules. If a module is defining a tracepoint it should be using it. - Add the tracepoint-update program to the ignore file The new tracepoint-update program needs to be ignored by git" * tag 'tracepoints-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: scripts: add tracepoint-update to the list of ignores files tracing: Add warnings for unused tracepoints for modules tracing: Allow tracepoint-update.c to work with modules tracepoint: Do not warn for unused event that is exported tracing: Add a tracepoint verification check at build time sorttable: Move ELF parsing into scripts/elf-parse.[ch]

Merge tag 'objtool-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-12-02T04:18:59+00:00

Pull objtool updates from Ingo Molnar: - klp-build livepatch module generation (Josh Poimboeuf) Introduce new objtool features and a klp-build script to generate livepatch modules using a source .patch as input. This builds on concepts from the longstanding out-of-tree kpatch project which began in 2012 and has been used for many years to generate livepatch modules for production kernels. However, this is a complete rewrite which incorporates hard-earned lessons from 12+ years of maintaining kpatch. Key improvements compared to kpatch-build: - Integrated with objtool: Leverages objtool's existing control-flow graph analysis to help detect changed functions. - Works on vmlinux.o: Supports late-linked objects, making it compatible with LTO, IBT, and similar. - Simplified code base: ~3k fewer lines of code. - Upstream: No more out-of-tree #ifdef hacks, far less cruft. - Cleaner internals: Vastly simplified logic for symbol/section/reloc inclusion and special section extraction. - Robust __LINE__ macro handling: Avoids false positive binary diffs caused by the __LINE__ macro by introducing a fix-patch-lines script which injects #line directives into the source .patch to preserve the original line numbers at compile time. - Disassemble code with libopcodes instead of running objdump (Alexandre Chartre) - Disassemble support (-d option to objtool) by Alexandre Chartre, which supports the decoding of various Linux kernel code generation specials such as alternatives: 17ef: sched_balance_find_dst_group+0x62f mov 0x34(%r9),%edx 17f3: sched_balance_find_dst_group+0x633 | | X86_FEATURE_POPCNT 17f3: sched_balance_find_dst_group+0x633 | call 0x17f8 <__sw_hweight64> | popcnt %rdi,%rax 17f8: sched_balance_find_dst_group+0x638 cmp %eax,%edx ... jump table alternatives: 1895: sched_use_asym_prio+0x5 test $0x8,%ch 1898: sched_use_asym_prio+0x8 je 0x18a9 189a: sched_use_asym_prio+0xa | | JUMP 189a: sched_use_asym_prio+0xa | jmp 0x18ae | nop2 189c: sched_use_asym_prio+0xc mov $0x1,%eax 18a1: sched_use_asym_prio+0x11 and $0x80,%ecx ... exception table alternatives: native_read_msr: 5b80: native_read_msr+0x0 mov %edi,%ecx 5b82: native_read_msr+0x2 | | EXCEPTION 5b82: native_read_msr+0x2 | rdmsr | resume at 0x5b84 5b84: native_read_msr+0x4 shl $0x20,%rdx .... x86 feature flag decoding (also see the X86_FEATURE_POPCNT example in sched_balance_find_dst_group() above): 2faaf: start_thread_common.constprop.0+0x1f jne 0x2fba4 2fab5: start_thread_common.constprop.0+0x25 | | X86_FEATURE_ALWAYS | X86_BUG_NULL_SEG 2fab5: start_thread_common.constprop.0+0x25 | jmp 0x2faba <.altinstr_aux+0x2f4> | jmp 0x4b0 | nop5 2faba: start_thread_common.constprop.0+0x2a mov $0x2b,%eax ... NOP sequence shortening: 1048e2: snapshot_write_finalize+0xc2 je 0x104917 1048e4: snapshot_write_finalize+0xc4 nop6 1048ea: snapshot_write_finalize+0xca nop11 1048f5: snapshot_write_finalize+0xd5 nop11 104900: snapshot_write_finalize+0xe0 mov %rax,%rcx 104903: snapshot_write_finalize+0xe3 mov 0x10(%rdx),%rax ... and much more. - Function validation tracing support (Alexandre Chartre) - Various -ffunction-sections fixes (Josh Poimboeuf) - Clang AutoFDO (Automated Feedback-Directed Optimizations) support (Josh Poimboeuf) - Misc fixes and cleanups (Borislav Petkov, Chen Ni, Dylan Hatch, Ingo Molnar, John Wang, Josh Poimboeuf, Pankaj Raghav, Peter Zijlstra, Thorsten Blum) * tag 'objtool-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (129 commits) objtool: Fix segfault on unknown alternatives objtool: Build with disassembly can fail when including bdf.h objtool: Trim trailing NOPs in alternative objtool: Add wide output for disassembly objtool: Compact output for alternatives with one instruction objtool: Improve naming of group alternatives objtool: Add Function to get the name of a CPU feature objtool: Provide access to feature and flags of group alternatives objtool: Fix address references in alternatives objtool: Disassemble jump table alternatives objtool: Disassemble exception table alternatives objtool: Print addresses with alternative instructions objtool: Disassemble group alternatives objtool: Print headers for alternatives objtool: Preserve alternatives order objtool: Add the --disas= action objtool: Do not validate IBT for .return_sites and .call_sites objtool: Improve tracing of alternative instructions objtool: Add functions to better name alternatives objtool: Identify the different types of alternatives ...

Merge tag 'vfs-6.19-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-12-01T16:44:26+00:00

Pull misc vfs updates from Christian Brauner: "Features: - Cheaper MAY_EXEC handling for path lookup. This elides MAY_WRITE permission checks during path lookup and adds the IOP_FASTPERM_MAY_EXEC flag so filesystems like btrfs can avoid expensive permission work. - Hide dentry_cache behind runtime const machinery. - Add German Maglione as virtiofs co-maintainer. Cleanups: - Tidy up and inline step_into() and walk_component() for improved code generation. - Re-enable IOCB_NOWAIT writes to files. This refactors file timestamp update logic, fixing a layering bypass in btrfs when updating timestamps on device files and improving FMODE_NOCMTIME handling in VFS now that nfsd started using it. - Path lookup optimizations extracting slowpaths into dedicated routines and adding branch prediction hints for mntput_no_expire(), fd_install(), lookup_slow(), and various other hot paths. - Enable clang's -fms-extensions flag, requiring a JFS rename to avoid conflicts. - Remove spurious exports in fs/file_attr.c. - Stop duplicating union pipe_index declaration. This depends on the shared kbuild branch that brings in -fms-extensions support which is merged into this branch. - Use MD5 library instead of crypto_shash in ecryptfs. - Use largest_zero_folio() in iomap_dio_zero(). - Replace simple_strtol/strtoul with kstrtoint/kstrtouint in init and initrd code. - Various typo fixes. Fixes: - Fix emergency sync for btrfs. Btrfs requires an explicit sync_fs() call with wait == 1 to commit super blocks. The emergency sync path never passed this, leaving btrfs data uncommitted during emergency sync. - Use local kmap in watch_queue's post_one_notification(). - Add hint prints in sb_set_blocksize() for LBS dependency on THP" * tag 'vfs-6.19-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits) MAINTAINERS: add German Maglione as virtiofs co-maintainer fs: inline step_into() and walk_component() fs: tidy up step_into() & friends before inlining orangefs: use inode_update_timestamps directly btrfs: fix the comment on btrfs_update_time btrfs: use vfs_utimes to update file timestamps fs: export vfs_utimes fs: lift the FMODE_NOCMTIME check into file_update_time_flags fs: refactor file timestamp update logic include/linux/fs.h: trivial fix: regualr -> regular fs/splice.c: trivial fix: pipes -> pipe's fs: mark lookup_slow() as noinline fs: add predicts based on nd->depth fs: move mntput_no_expire() slowpath into a dedicated routine fs: remove spurious exports in fs/file_attr.c watch_queue: Use local kmap in post_one_notification() fs: touch up predicts in path lookup fs: move fd_install() slowpath into a dedicated routine and provide commentary fs: hide dentry_cache behind runtime const machinery fs: touch predicts in do_dentry_open() ...

kbuild: Check for functions with ambiguous -ffunction-sections section names

2025-11-21T09:04:10+00:00

Commit 9c7dc1dd897a ("objtool: Warn on functions with ambiguous -ffunction-sections section names") only works for drivers which are compiled on architectures supported by objtool. Make a script to perform the same check for all architectures. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/a6a49644a34964f7e02f3a8ce43af03e72817180.1763669451.git.jpoimboe@kernel.org

objtool: Warn on functions with ambiguous -ffunction-sections section names

2025-11-13T07:03:10+00:00

When compiled with -ffunction-sections, a function named startup() will be placed in .text.startup. However, .text.startup is also used by the compiler for functions with __attribute__((constructor)). That creates an ambiguity for the vmlinux linker script, which needs to differentiate those two cases. Similar naming conflicts exist for functions named exit(), split(), unlikely(), hot() and unknown(). One potential solution would be to use '#ifdef CC_USING_FUNCTION_SECTIONS' to create two distinct implementations of the TEXT_MAIN macro. However, -ffunction-sections can be (and is) enabled or disabled on a per-object basis (for example via ccflags-y or AUTOFDO_PROFILE). So the recently unified TEXT_MAIN macro (commit 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros")) is necessary. This means there's no way for the linker script to disambiguate things. Instead, use objtool to warn on any function names whose resulting section names might create ambiguity when the kernel is compiled (in whole or in part) with -ffunction-sections. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: live-patching@vger.kernel.org Cc: Linus Torvalds Link: https://patch.msgid.link/65fedea974fe14be487c8867a0b8d0e4a294ce1e.1762991150.git.jpoimboe@kernel.org

vmlinux.lds: Fix TEXT_MAIN to include .text.start and friends

2025-11-13T07:03:09+00:00

Since: 6568f14cb5ae ("vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN") the TEXT_MAIN macro uses a series of patterns to prevent the .text.startup[.*] and .text.exit[.*] sections from getting linked into the vmlinux runtime .text. That commit is a tad too aggressive: it also inadvertently filters out valid runtime text sections like .text.start and .text.start.constprop.0, which can be generated for a function named start() when -ffunction-sections is enabled. As a result, those sections become orphans when building with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION for arm: arm-linux-gnueabi-ld: warning: orphan section `.text.start.constprop.0' from `drivers/usb/host/sl811-hcd.o' being placed in section `.text.start.constprop.0' arm-linux-gnueabi-ld: warning: orphan section `.text.start.constprop.0' from `drivers/media/dvb-frontends/drxk_hard.o' being placed in section `.text.start.constprop.0' arm-linux-gnueabi-ld: warning: orphan section `.text.start' from `drivers/media/dvb-frontends/stv0910.o' being placed in section `.text.start' arm-linux-gnueabi-ld: warning: orphan section `.text.start.constprop.0' from `drivers/media/pci/ddbridge/ddbridge-sx8.o' being placed in section `.text.start.constprop.0' Fix that by explicitly adding the partial "substring" sections (.text.s, .text.st, .text.sta, etc) and their cloned derivatives. While this unfortunately means that TEXT_MAIN continues to grow, these changes are ultimately necessary for proper support of -ffunction-sections. Fixes: 6568f14cb5ae ("vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN") Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: live-patching@vger.kernel.org Cc: Linus Torvalds Link: https://patch.msgid.link/cd588144e63df901a656b06b566855019c4a931d.1762991150.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/oe-kbuild-all/202511040812.DFGedJiy-lkp@intel.com/

Merge tag 'v6.18-rc5' into objtool/core, to pick up fixes

2025-11-13T06:58:43+00:00

Signed-off-by: Ingo Molnar

fs: hide dentry_cache behind runtime const machinery

2025-11-12T11:19:09+00:00

Signed-off-by: Mateusz Guzik Link: https://patch.msgid.link/20251105153622.758836-1-mjguzik@gmail.com Signed-off-by: Christian Brauner

vmlinux.lds: Exclude .text.startup and .text.exit from TEXT_MAIN

2025-10-31T10:19:21+00:00

An ftrace warning was reported in ftrace_init_ool_stub(): WARNING: arch/powerpc/kernel/trace/ftrace.c:234 at ftrace_init_ool_stub+0x188/0x3f4, CPU#0: swapper/0 The problem is that the linker script is placing .text.startup in .text rather than in .init.text, due to an inadvertent match of the TEXT_MAIN '.text.[0-9a-zA-Z_]*' pattern. This bug existed for some configurations before, but is only now coming to light due to the TEXT_MAIN macro unification in commit 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros"). The .text.startup section consists of constructors which are used by KASAN, KCSAN, and GCOV. The constructors are only called during boot, so .text.startup is supposed to match the INIT_TEXT pattern so it can be placed in .init.text and freed after init. But since INIT_TEXT comes *after* TEXT_MAIN in the linker script, TEXT_MAIN needs to manually exclude .text.startup. Update TEXT_MAIN to exclude .text.startup (and its .text.startup.* variant from -ffunction-sections), along with .text.exit and .text.exit.* which should match EXIT_TEXT. Specifically, use a series of more specific glob patterns to match generic .text.* sections (for -ffunction-sections) while explicitly excluding .text.startup[.*] and .text.exit[.*]. Also update INIT_TEXT and EXIT_TEXT to explicitly match their -ffunction-sections variants (.text.startup.* and .text.exit.*). Fixes: 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros") Closes: https://lore.kernel.org/72469502-ca37-4287-90b9-a751cecc498c@linux.ibm.com Reported-by: Venkat Rao Bagalkote Debugged-by: Hari Bathini Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Tested-by: Venkat Rao Bagalkote Link: https://patch.msgid.link/07f74b4e5c43872572b7def30f2eac45f28675d9.1761872421.git.jpoimboe@kernel.org