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| author | Ulises Mendez Martinez <umendez@google.com> | 2026-09-04 15:07:09 +0000 |
|---|---|---|
| committer | Josh Poimboeuf <jpoimboe@kernel.org> | 2026-09-13 18:15:43 -0700 |
| commit | 7e61560628d17ea6b1d8ee370f6d42694cff8758 (patch) | |
| tree | e6080164b2f4c4c419894bdb3ce4d956ca9a98c5 /Documentation/userspace-api/ELF.rst | |
| download | linux-stable-7e61560628d17ea6b1d8ee370f6d42694cff8758.tar.gz linux-stable-7e61560628d17ea6b1d8ee370f6d42694cff8758.zip | |
objtool: Validate disassembler headers in libopcodes probegrafted
commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
tested for libopcodes availability by linking a test snippet with a forward
declaration of disassemble_init_for_target().
However, testing symbol linkage with an extern declaration only verifies
the presence of the library (.so/.a) and bypasses checking for development
headers (binutils-dev). On systems where libopcodes is present without
development headers installed, the probe succeeds, enabling BUILD_DISAS.
Subsequent compilation of objtool then fails:
fatal error: 'bfd.h' file not found
113 | #include <bfd.h>
Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring
any sysroot or include flags specified for the host compiler.
Fix this by including <bfd.h> and <dis-asm.h> directly in the test snippet,
passing $(HOSTCFLAGS) so host compiler options are respected, and defining
PACKAGE="objtool" to satisfy the configuration check in <bfd.h>.
Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check")
Reported-by: Alice Ryhl <aliceryhl@google.com>
Assisted-by: Antigravity:Gemini-Next
Signed-off-by: Ulises Mendez Martinez <umendez@google.com>
Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Diffstat (limited to 'Documentation/userspace-api/ELF.rst')
| -rw-r--r-- | Documentation/userspace-api/ELF.rst | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/Documentation/userspace-api/ELF.rst b/Documentation/userspace-api/ELF.rst new file mode 100644 index 000000000..ac8aeacd4 --- /dev/null +++ b/Documentation/userspace-api/ELF.rst @@ -0,0 +1,34 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================= +Linux-specific ELF idiosyncrasies +================================= + +Definitions +=========== + +"First" program header is the one with the smallest offset in the file: +e_phoff. + +"Last" program header is the one with the biggest offset in the file: +e_phoff + (e_phnum - 1) * sizeof(Elf_Phdr). + +PT_INTERP +========= + +First PT_INTERP program header is used to locate the filename of ELF +interpreter. Other PT_INTERP headers are ignored (since Linux 2.4.11). + +PT_GNU_STACK +============ + +Last PT_GNU_STACK program header defines userspace stack executability +(since Linux 2.6.6). Other PT_GNU_STACK headers are ignored. + +PT_GNU_PROPERTY +=============== + +ELF interpreter's last PT_GNU_PROPERTY program header is used (since +Linux 5.8). If interpreter doesn't have one, then the last PT_GNU_PROPERTY +program header of an executable is used. Other PT_GNU_PROPERTY headers +are ignored. |