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commit 7912405643a14b527cd4a4f33c1d4392da900888 upstream.
The compiler can fully inline the actual handler function of an interrupt
entry into the .irqentry.text entry point. If such a function contains an
access which has an exception table entry, modpost complains about a
section mismatch:
WARNING: vmlinux.o(__ex_table+0x447c): Section mismatch in reference ...
The relocation at __ex_table+0x447c references section ".irqentry.text"
which is not in the list of authorized sections.
Add .irqentry.text to OTHER_SECTIONS to cure the issue.
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org # needed for linux-5.4-y
Link: https://lore.kernel.org/all/20241128111844.GE10431@google.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 ]
The > comparison should be >= to prevent an out of bounds array
access.
Fixes: 52dc0595d540 ("modpost: handle relocations mismatch in __ex_table.")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d ]
addend_arm_rel() processes R_ARM_PC24, R_ARM_CALL, R_ARM_JUMP24 in a
wrong way.
Here, test code.
[test code for R_ARM_JUMP24]
.section .init.text,"ax"
bar:
bx lr
.section .text,"ax"
.globl foo
foo:
b bar
[test code for R_ARM_CALL]
.section .init.text,"ax"
bar:
bx lr
.section .text,"ax"
.globl foo
foo:
push {lr}
bl bar
pop {pc}
If you compile it with ARM multi_v7_defconfig, modpost will show the
symbol name, (unknown).
WARNING: modpost: vmlinux.o: section mismatch in reference: foo (section: .text) -> (unknown) (section: .init.text)
(You need to use GNU linker instead of LLD to reproduce it.)
Fix the code to make modpost show the correct symbol name.
I imported (with adjustment) sign_extend32() from include/linux/bitops.h.
The '+8' is the compensation for pc-relative instruction. It is
documented in "ELF for the Arm Architecture" [1].
"If the relocation is pc-relative then compensation for the PC bias
(the PC value is 8 bytes ahead of the executing instruction in Arm
state and 4 bytes in Thumb state) must be encoded in the relocation
by the object producer."
[1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst
Fixes: 56a974fa2d59 ("kbuild: make better section mismatch reports on arm")
Fixes: 6e2e340b59d2 ("ARM: 7324/1: modpost: Fix section warnings for ARM for many compilers")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b7c63520f6703a25eebb4f8138fed764fcae1c6f ]
addend_arm_rel() processes R_ARM_ABS32 in a wrong way.
Here, test code.
[test code 1]
#include <linux/init.h>
int __initdata foo;
int get_foo(void) { return foo; }
If you compile it with ARM versatile_defconfig, modpost will show the
symbol name, (unknown).
WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> (unknown) (section: .init.data)
(You need to use GNU linker instead of LLD to reproduce it.)
If you compile it for other architectures, modpost will show the correct
symbol name.
WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data)
For R_ARM_ABS32, addend_arm_rel() sets r->r_addend to a wrong value.
I just mimicked the code in arch/arm/kernel/module.c.
However, there is more difficulty for ARM.
Here, test code.
[test code 2]
#include <linux/init.h>
int __initdata foo;
int get_foo(void) { return foo; }
int __initdata bar;
int get_bar(void) { return bar; }
With this commit applied, modpost will show the following messages
for ARM versatile_defconfig:
WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data)
WARNING: modpost: vmlinux.o: section mismatch in reference: get_bar (section: .text) -> foo (section: .init.data)
The reference from 'get_bar' to 'foo' seems wrong.
I have no solution for this because it is true in assembly level.
In the following output, relocation at 0x1c is no longer associated
with 'bar'. The two relocation entries point to the same symbol, and
the offset to 'bar' is encoded in the instruction 'r0, [r3, #4]'.
Disassembly of section .text:
00000000 <get_foo>:
0: e59f3004 ldr r3, [pc, #4] @ c <get_foo+0xc>
4: e5930000 ldr r0, [r3]
8: e12fff1e bx lr
c: 00000000 .word 0x00000000
00000010 <get_bar>:
10: e59f3004 ldr r3, [pc, #4] @ 1c <get_bar+0xc>
14: e5930004 ldr r0, [r3, #4]
18: e12fff1e bx lr
1c: 00000000 .word 0x00000000
Relocation section '.rel.text' at offset 0x244 contains 2 entries:
Offset Info Type Sym.Value Sym. Name
0000000c 00000c02 R_ARM_ABS32 00000000 .init.data
0000001c 00000c02 R_ARM_ABS32 00000000 .init.data
When find_elf_symbol() gets into a situation where relsym->st_name is
zero, there is no guarantee to get the symbol name as written in C.
I am keeping the current logic because it is useful in many architectures,
but the symbol name is not always correct depending on the optimization.
I left some comments in find_tosym().
Fixes: 56a974fa2d59 ("kbuild: make better section mismatch reports on arm")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 28438794aba47a27e922857d27b31b74e8559143 upstream.
Since commit f02e8a6596b7 ("module: Sort exported symbols"),
EXPORT_SYMBOL* is placed in the individual section ___ksymtab(_gpl)+<sym>
(3 leading underscores instead of 2).
Since then, modpost cannot detect the bad combination of EXPORT_SYMBOL
and __init/__exit.
Fix the .fromsec field.
Fixes: f02e8a6596b7 ("module: Sort exported symbols")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit d6b732666a1bae0df3c3ae06925043bba34502b1 ]
The return value of is_arm_mapping_symbol() is unpredictable when "$"
is passed in.
strchr(3) says:
The strchr() and strrchr() functions return a pointer to the matched
character or NULL if the character is not found. The terminating null
byte is considered part of the string, so that if c is specified as
'\0', these functions return a pointer to the terminator.
When str[1] is '\0', strchr("axtd", str[1]) is not NULL, and str[2] is
referenced (i.e. buffer overrun).
Test code
---------
char str1[] = "abc";
char str2[] = "ab";
strcpy(str1, "$");
strcpy(str2, "$");
printf("test1: %d\n", is_arm_mapping_symbol(str1));
printf("test2: %d\n", is_arm_mapping_symbol(str2));
Result
------
test1: 0
test2: 1
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b5beffa20d83c4e15306c991ffd00de0d8628338 ]
With the `-z unique-symbol` linker flag or any similar mechanism,
it is possible to trigger the following:
ERROR: modpost: "param_set_uint.0" [vmlinux] is a static EXPORT_SYMBOL
The reason is that for now the condition from remove_dot():
if (m && (s[n + m] == '.' || s[n + m] == 0))
which was designed to test if it's a dot or a '\0' after the suffix
is never satisfied.
This is due to that `s[n + m]` always points to the last digit of a
numeric suffix, not on the symbol next to it (from a custom debug
print added to modpost):
param_set_uint.0, s[n + m] is '0', s[n + m + 1] is '\0'
So it's off-by-one and was like that since 2014.
Fix this for the sake of any potential upcoming features, but don't
bother stable-backporting, as it's well hidden -- apart from that
LD flag, it can be triggered only with GCC LTO which never landed
upstream.
Fixes: fcd38ed0ff26 ("scripts: modpost: fix compilation warning")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 6553896666433e7efec589838b400a2a652b3ffa ]
Some code pathes, especially the low level entry code, must be protected
against instrumentation for various reasons:
- Low level entry code can be a fragile beast, especially on x86.
- With NO_HZ_FULL RCU state needs to be established before using it.
Having a dedicated section for such code allows to validate with tooling
that no unsafe functions are invoked.
Add the .noinstr.text section and the noinstr attribute to mark
functions. noinstr implies notrace. Kprobes will gain a section check
later.
Provide also a set of markers: instrumentation_begin()/end()
These are used to mark code inside a noinstr function which calls
into regular instrumentable text section as safe.
The instrumentation markers are only active when CONFIG_DEBUG_ENTRY is
enabled as the end marker emits a NOP to prevent the compiler from merging
the annotation points. This means the objtool verification requires a
kernel compiled with this option.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134100.075416272@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 5190044c2965514a973184ca68ef5fad57a24670 upstream.
In order to preserve backwards compatability with kmod tools, we have to
move the namespace field in Module.symvers last, as the depmod -e -E
option looks at the first three fields in Module.symvers to check symbol
versions (and it's expected they stay in the original order of crc,
symbol, module).
In addition, update an ancient comment above read_dump() in modpost that
suggested that the export type field in Module.symvers was optional. I
suspect that there were historical reasons behind that comment that are
no longer accurate. We have been unconditionally printing the export
type since 2.6.18 (commit bd5cbcedf44), which is over a decade ago now.
Fix up read_dump() to treat each field as non-optional. I suspect the
original read_dump() code treated the export field as optional in order
to support pre <= 2.6.18 Module.symvers (which did not have the export
type field). Note that although symbol namespaces are optional, the
field will not be omitted from Module.symvers if a symbol does not have
a namespace. In this case, the field will simply be empty and the next
delimiter or end of line will follow.
Cc: stable@vger.kernel.org
Fixes: cb9b55d21fe0 ("modpost: add support for symbol namespaces")
Tested-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The introduction of Symbol Namespaces changed the naming schema of the
__ksymtab entries from __kysmtab__symbol to __ksymtab_NAMESPACE.symbol.
That caused some breakages in tools that depend on the name layout in
either the binaries(vmlinux,*.ko) or in System.map. E.g. kmod's depmod
would not be able to read System.map without a patch to support symbol
namespaces. A warning reported by depmod for namespaced symbols would
look like
depmod: WARNING: [...]/uas.ko needs unknown symbol usb_stor_adjust_quirks
In order to address this issue, revert to the original naming scheme and
rather read the __kstrtabns_<symbol> entries and their corresponding
values from __ksymtab_strings to update the namespace values for
symbols. After having read all symbols and handled them in
handle_modversions(), the symbols are created. In a second pass, read
the __kstrtabns_ entries and update the namespaces accordingly.
Fixes: 8651ec01daed ("module: add support for symbol namespaces.")
Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Setting the symbol namespace of a symbol within sym_add_exported feels
displaced and lead to issues in the current implementation of symbol
namespaces. This patch makes updating the namespace an explicit call to
decouple it from adding a symbol to the export list.
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Let the function 'sym_update_namespace' take care of updating the
namespace for a symbol. While this currently only replaces one single
location where namespaces are updated, in a following patch, this
function will get more call sites.
The function signature is intentionally close to sym_update_crc and
taking the name by char* seems like unnecessary work as the symbol has
to be looked up again. In a later patch of this series, this concern
will be addressed.
This function ensures that symbol::namespace is either NULL or has a
valid non-empty value. Previously, the empty string was considered 'no
namespace' as well and this lead to confusion.
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull module fixes from Jessica Yu:
"Code cleanups and kbuild/namespace related fixups from Masahiro.
Most importantly, it fixes a namespace-related modpost issue for
external module builds
- Fix broken external module builds due to a modpost bug in
read_dump(), where the namespace was not being strdup'd and
sym->namespace would be set to bogus data.
- Various namespace-related kbuild fixes and cleanups thanks to
Masahiro Yamada"
* tag 'modules-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
doc: move namespaces.rst from kbuild/ to core-api/
nsdeps: make generated patches independent of locale
nsdeps: fix hashbang of scripts/nsdeps
kbuild: fix build error of 'make nsdeps' in clean tree
module: rename __kstrtab_ns_* to __kstrtabns_* to avoid symbol conflict
modpost: fix broken sym->namespace for external module builds
module: swap the order of symbol.namespace
scripts: add_namespace: Fix coccicheck failed
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Currently, external module builds produce tons of false-positives:
WARNING: module <mod> uses symbol <sym> from namespace <ns>, but does not import it.
Here, the <ns> part shows a random string.
When you build external modules, the symbol info of vmlinux and
in-kernel modules are read from $(objtree)/Module.symvers, but
read_dump() is buggy in multiple ways:
[1] When the modpost is run for vmlinux and in-kernel modules,
sym_extract_namespace() allocates memory for the namespace. On the
other hand, read_dump() does not, then sym->namespace will point to
somewhere in the line buffer of get_next_line(). The data in the
buffer will be replaced soon, and sym->namespace will end up with
pointing to unrelated data. As a result, check_exports() will show
random strings in the warning messages.
[2] When there is no namespace, sym_extract_namespace() returns NULL.
On the other hand, read_dump() sets namespace to an empty string "".
(but, it will be later replaced with unrelated data due to bug [1].)
The check_exports() shows a warning unless exp->namespace is NULL,
so every symbol read from read_dump() emits the warning, which is
mostly false positive.
To address [1], sym_add_exported() calls strdup() for s->namespace.
The namespace from sym_extract_namespace() must be freed to avoid
memory leak.
For [2], I changed the if-conditional in check_exports().
This commit also fixes sym_add_exported() to set s->namespace correctly
when the symbol is preloaded.
Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Currently, EXPORT_SYMBOL_NS(_GPL) constructs the kernel symbol as
follows:
__ksymtab_SYMBOL.NAMESPACE
The sym_extract_namespace() in modpost allocates memory for the part
SYMBOL.NAMESPACE when '.' is contained. One problem is that the pointer
returned by strdup() is lost because the symbol name will be copied to
malloc'ed memory by alloc_symbol(). No one will keep track of the
pointer of strdup'ed memory.
sym->namespace still points to the NAMESPACE part. So, you can free it
with complicated code like this:
free(sym->namespace - strlen(sym->name) - 1);
It complicates memory free.
To fix it elegantly, I swapped the order of the symbol and the
namespace as follows:
__ksymtab_NAMESPACE.SYMBOL
then, simplified sym_extract_namespace() so that it allocates memory
only for the NAMESPACE part.
I prefer this order because it is intuitive and also matches to major
languages. For example, NAMESPACE::NAME in C++, MODULE.NAME in Python.
Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Johannes Berg reports lots of modpost warnings on ARCH=um builds:
WARNING: "rename" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "lseek" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "ftruncate64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "getuid" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "lseek64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "unlink" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "pwrite64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "close" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "opendir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "pread64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "syscall" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "readdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "readdir64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "futimes" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__lxstat" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "write" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "closedir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__xstat" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fsync" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__lxstat64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__fxstat64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "telldir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "printf" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "readlink" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__sprintf_chk" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "link" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "rmdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fdatasync" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "truncate" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "statfs" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__errno_location" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__xmknod" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "open64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "truncate64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "open" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "read" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "chown" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "chmod" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "utime" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fchmod" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "seekdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "ioctl" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "dup2" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "statfs64" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "utimes" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "mkdir" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "fchown" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__guard" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "symlink" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "access" [vmlinux] is a static EXPORT_SYMBOL
WARNING: "__stack_smash_handler" [vmlinux] is a static EXPORT_SYMBOL
When you run "make", the modpost is run twice; before linking vmlinux,
and before building modules. All the warnings above are from the second
modpost.
The offending symbols are defined not in vmlinux, but in the C library.
The first modpost is run against the relocatable vmlinux.o, and those
warnings are nicely suppressed because the SH_UNDEF entries from the
symbol table clear the ->is_static flag.
The second modpost is run against the executable vmlinux (+ modules),
where those symbols have been resolved, but the definitions do not
exist.
This commit fixes it in a straightforward way; suppress the static
EXPORT_SYMBOL warnings from "vmlinux".
Without this commit, we see valid warnings twice anyway. For example,
ARCH=arm64 defconfig shows the following warning twice:
WARNING: "HYPERVISOR_platform_op" [vmlinux] is a static EXPORT_SYMBOL_GPL
So, it is reasonable to suppress the second one.
Fixes: 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Denis Efremov <efremov@linux.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"The main bulk of this pull request introduces a new exported symbol
namespaces feature. The number of exported symbols is increasingly
growing with each release (we're at about 31k exports as of 5.3-rc7)
and we currently have no way of visualizing how these symbols are
"clustered" or making sense of this huge export surface.
Namespacing exported symbols allows kernel developers to more
explicitly partition and categorize exported symbols, as well as more
easily limiting the availability of namespaced symbols to other parts
of the kernel. For starters, we have introduced the USB_STORAGE
namespace to demonstrate the API's usage. I have briefly summarized
the feature and its main motivations in the tag below.
Summary:
- Introduce exported symbol namespaces.
This new feature allows subsystem maintainers to partition and
categorize their exported symbols into explicit namespaces. Module
authors are now required to import the namespaces they need.
Some of the main motivations of this feature include: allowing
kernel developers to better manage the export surface, allow
subsystem maintainers to explicitly state that usage of some
exported symbols should only be limited to certain users (think:
inter-module or inter-driver symbols, debugging symbols, etc), as
well as more easily limiting the availability of namespaced symbols
to other parts of the kernel.
With the module import requirement, it is also easier to spot the
misuse of exported symbols during patch review.
Two new macros are introduced: EXPORT_SYMBOL_NS() and
EXPORT_SYMBOL_NS_GPL(). The API is thoroughly documented in
Documentation/kbuild/namespaces.rst.
- Some small code and kbuild cleanups here and there"
* tag 'modules-for-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Remove leftover '#undef' from export header
module: remove unneeded casts in cmp_name()
module: move CONFIG_UNUSED_SYMBOLS to the sub-menu of MODULES
module: remove redundant 'depends on MODULES'
module: Fix link failure due to invalid relocation on namespace offset
usb-storage: export symbols in USB_STORAGE namespace
usb-storage: remove single-use define for debugging
docs: Add documentation for Symbol Namespaces
scripts: Coccinelle script for namespace dependencies.
modpost: add support for generating namespace dependencies
export: allow definition default namespaces in Makefiles or sources
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
modpost: add support for symbol namespaces
module: add support for symbol namespaces.
export: explicitly align struct kernel_symbol
module: support reading multiple values per modinfo tag
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Use the __section() shorthand. This avoids escaping double-quotes,
and improves the readability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This makes *.mod.c much more readable. I confirmed depmod still
produced the same modules.dep file.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This patch adds an option to modpost to generate a <module>.ns_deps file
per module, containing the namespace dependencies for that module.
E.g. if the linked module my-module.ko would depend on the symbol
myfunc.MY_NS in the namespace MY_NS, the my-module.ns_deps file created
by modpost would contain the entry MY_NS to express the namespace
dependency of my-module imposed by using the symbol myfunc.
These files can subsequently be used by static analysis tools (like
coccinelle scripts) to address issues with missing namespace imports. A
later patch of this series will introduce such a script 'nsdeps' and a
corresponding make target to automatically add missing
MODULE_IMPORT_NS() definitions to the module's sources. For that it uses
the information provided in the generated .ns_deps files.
Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Add support for symbols that are exported into namespaces. For that,
extract any namespace suffix from the symbol name. In addition, emit a
warning whenever a module refers to an exported symbol without
explicitly importing the namespace that it is defined in. This patch
consistently adds the namespace suffix to symbol names exported into
Module.symvers.
Example warning emitted by modpost in case of the above violation:
WARNING: module ums-usbat uses symbol usb_stor_resume from namespace
USB_STORAGE, but does not import it.
Co-developed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Add NOFAIL check for the strndup call, because the function
allocates memory and can return NULL. All calls to strdup in
modpost are checked with NOFAIL.
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This patch adds a check to warn about static EXPORT_SYMBOL* functions
during the modpost. In most of the cases, a static symbol marked for
exporting is an odd combination that should be fixed either by deleting
the exporting mark or by removing the static attribute and adding the
appropriate declaration to headers.
This check could help to detect the following problems:
1. 550113d4e9f5 ("i2c: add newly exported functions to the header, too")
2. 54638c6eaf44 ("net: phy: make exported variables non-static")
3. 98ef2046f28b ("mm: remove the exporting of totalram_pages")
4. 73df167c819e ("s390/zcrypt: remove the exporting of ap_query_configuration")
5. a57caf8c527f ("sunrpc/cache: remove the exporting of cache_seq_next")
6. e4e4730698c9 ("crypto: skcipher - remove the exporting of skcipher_walk_next")
7. 14b4c48bb1ce ("gve: Remove the exporting of gve_probe")
8. 9b79ee9773a8 ("scsi: libsas: remove the exporting of sas_wait_eh")
9. ...
The build time impact is very limited and is almost at the unnoticeable
level (< 1 sec).
Acked-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Fix commit 56067812d5b0 ("kbuild: modversions: add infrastructure for
emitting relative CRCs") where CRCs are interpreted in host byte order
rather than proper kernel byte order. The bug is conditional on
CONFIG_MODULE_REL_CRCS.
For example, when loading a BE module into a BE kernel compiled with a LE
system, the error "disagrees about version of symbol module_layout" is
produced. A message such as "Found checksum D7FA6856 vs module 5668FAD7"
will be given with debug enabled, which indicates an obvious endian
problem within __kcrctab within the kernel image.
The general solution is to use the macro TO_NATIVE, as is done in
similar cases throughout modpost.c. With this correction it has been
verified that a BE kernel compiled with a LE system accepts BE modules.
This change has also been verified with a LE kernel compiled with a LE
system, in which case TO_NATIVE returns its value unmodified since the
byte orders match. This is by far the common case.
Fixes: 56067812d5b0 ("kbuild: modversions: add infrastructure for emitting relative CRCs")
Signed-off-by: Fredrik Noring <noring@nocrew.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Unless CONFIG_DEBUG_SECTION_MISMATCH is enabled, modpost only shows
the number of section mismatches.
If you want to know the symbols causing the issue, you need to rebuild
with CONFIG_DEBUG_SECTION_MISMATCH. It is tedious.
I think it is fine to show annoying warning when a new section mismatch
comes in.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Commit
4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
replaced the RETPOLINE define with CONFIG_RETPOLINE checks. Remove the
remaining pieces.
[ bp: Massage commit message. ]
Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support")
Signed-off-by: WANG Chao <chao.wang@ucloud.cn>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: linux-kbuild@vger.kernel.org
Cc: srinivas.eeda@oracle.com
Cc: stable <stable@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20181210163725.95977-1-chao.wang@ucloud.cn
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This will fit better in check_exports() than add_versions().
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Probably, this is just a matter of the order of error/warning
messages. Merge the two for-loops.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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You do not need to iterate over all modules for resetting ->seen flag
because add_depends() is only interested in modules that export symbols
referenced from the given 'mod'.
This also avoids shadowing the 'modules' parameter of add_depends().
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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During development of a serial console driver with a gcc 8.2.0
toolchain for RISC-V, the following modpost warning appeared:
----
WARNING: vmlinux.o(.data+0x19b10): Section mismatch in reference from the variable .LANCHOR1 to the function .init.text:sifive_serial_console_setup()
The variable .LANCHOR1 references
the function __init sifive_serial_console_setup()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console
----
".LANCHOR1" is an ELF local symbol, automatically created by gcc's section
anchor generation code:
https://gcc.gnu.org/onlinedocs/gccint/Anchored-Addresses.html
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/varasm.c;h=cd9591a45617464946dcf9a126dde277d9de9804;hb=9fb89fa845c1b2e0a18d85ada0b077c84508ab78#l7473
This was verified by compiling the kernel with -fno-section-anchors
and observing that the ".LANCHOR1" ELF local symbol disappeared, and
modpost no longer warned about the section mismatch. The serial
driver code idiom triggering the warning is standard Linux serial
driver practice that has a specific whitelist inclusion in modpost.c.
I'm neither a modpost nor an ELF expert, but naively, it doesn't seem
useful for modpost to report section mismatch warnings caused by ELF
local symbols by default. Local symbols have compiler-generated
names, and thus bypass modpost's whitelisting algorithm, which relies
on the presence of a non-autogenerated symbol name. This increases
the likelihood that false positive warnings will be generated (as in
the above case).
Thus, disable section mismatch reporting on ELF local symbols. The
rationale here is similar to that of commit 2e3a10a1551d ("ARM: avoid
ARM binutils leaking ELF local symbols") and of similar code already
present in modpost.c:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/mod/modpost.c?h=v4.19-rc4&id=7876320f88802b22d4e2daf7eb027dd14175a0f8#n1256
This third version of the patch implements a suggestion from Masahiro
Yamada <yamada.masahiro@socionext.com> to restructure the code as an
additional pattern matching step inside secref_whitelist(), and
further improves the patch description.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Drop modpost command line switches that are no longer used by
makefile.modpost, upon request from Sam Ravnborg <sam@ravnborg.org>,
who wrote:
modpost is not supposed to be used outside the kernel build. [...]
I checked if there were any options supported by modpost that
was not configurable in Makefile.modpost.
And I could see that the -M and -K options in getopt() were leftovers.
The code that used these option was dropped in:
commit a8773769d1a1 ("Kbuild: clear marker out of modpost")
Could you add a patch that delete these on top of what you already have.
https://lore.kernel.org/lkml/20181020140835.GA3351@ravnborg.org/
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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If an ARM mapping symbol shares an address with a valid symbol,
find_elf_symbol can currently return the mapping symbol instead, as the
symbol is not validated. This can result in confusing warnings:
WARNING: vmlinux.o(.text+0x18f4028): Section mismatch in reference
from the function set_reset_devices() to the variable .init.text:$x.0
This change adds a call to is_valid_name to find_elf_symbol, similarly
to how it's already used in find_elf_symbol2.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Fix missing error check for memory allocation functions in
scripts/mod/modpost.c.
Fixes kernel bugzilla #200319:
https://bugzilla.kernel.org/show_bug.cgi?id=200319
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Yuexing Wang <wangyxlandq@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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In Fedora, the debug information is packaged separately (foo-debuginfo) and
can be installed separately. There's been a long standing issue where only
one version of a debuginfo info package can be installed at a time. There's
been an effort for Fedora for parallel debuginfo to rectify this problem.
Part of the requirement to allow parallel debuginfo to work is that build ids
are unique between builds. The existing upstream rpm implementation ensures
this by re-calculating the build-id using the version and release as a
seed. This doesn't work 100% for the kernel because of the vDSO which is
its own binary and doesn't get updated when embedded.
Fix this by adding some data in an ELF note for both the kernel and modules.
The data is controlled via a Kconfig option so distributions can set it
to an appropriate value to ensure uniqueness between builds.
Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Neither find_module() nor read_symbols() does change *modname.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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The second test of is_vmlinux() is redundant.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Currently, strstarts() is only used in export_from_secname().
Use it more widely to improve the code readability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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get_(next_)modinfo takes a pointer and length pair of the .modinfo
section. Instead, pass struct elf_info pointer to reduce the number
of function arguments.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG.
They were removed by commit 4ba66a976072 ("arch: remove blackfin port"),
commit bb6fb6dfcc17 ("metag: Remove arch/metag/"), respectively.
No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX,
hence VMLINUX_SYMBOL_STR(foo) can be simplify replaced with "foo".
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
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Remove the MN10300 arch as the hardware is defunct.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Masahiro Yamada <yamada.masahiro@socionext.com>
cc: linux-am33-list@redhat.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"Minor code cleanups and MAINTAINERS update"
* tag 'modules-for-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
modpost: Remove trailing semicolon
ftrace/module: Move ftrace_release_mod() to ddebug_cleanup label
MAINTAINERS: Remove from module & paravirt maintenance
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/pti updates from Thomas Gleixner:
"Another set of melted spectrum related changes:
- Code simplifications and cleanups for RSB and retpolines.
- Make the indirect calls in KVM speculation safe.
- Whitelist CPUs which are known not to speculate from Meltdown and
prepare for the new CPUID flag which tells the kernel that a CPU is
not affected.
- A less rigorous variant of the module retpoline check which merily
warns when a non-retpoline protected module is loaded and reflects
that fact in the sysfs file.
- Prepare for Indirect Branch Prediction Barrier support.
- Prepare for exposure of the Speculation Control MSRs to guests, so
guest OSes which depend on those "features" can use them. Includes
a blacklist of the broken microcodes. The actual exposure of the
MSRs through KVM is still being worked on"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Simplify indirect_branch_prediction_barrier()
x86/retpoline: Simplify vmexit_fill_RSB()
x86/cpufeatures: Clean up Spectre v2 related CPUID flags
x86/cpu/bugs: Make retpoline module warning conditional
x86/bugs: Drop one "mitigation" from dmesg
x86/nospec: Fix header guards names
x86/alternative: Print unadorned pointers
x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
x86/msr: Add definitions for new speculation control MSRs
x86/cpufeatures: Add AMD feature bits for Speculation Control
x86/cpufeatures: Add Intel feature bits for Speculation Control
x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
module/retpoline: Warn about missing retpoline in module
KVM: VMX: Make indirect call speculation safe
KVM: x86: Make indirect calls in emulator speculation safe
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There's a risk that a kernel which has full retpoline mitigations becomes
vulnerable when a module gets loaded that hasn't been compiled with the
right compiler or the right option.
To enable detection of that mismatch at module load time, add a module info
string "retpoline" at build time when the module was compiled with
retpoline support. This only covers compiled C source, but assembler source
or prebuilt object files are not checked.
If a retpoline enabled kernel detects a non retpoline protected module at
load time, print a warning and report it in the sysfs vulnerability file.
[ tglx: Massaged changelog ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: gregkh@linuxfoundation.org
Cc: torvalds@linux-foundation.org
Cc: jeyu@kernel.org
Cc: arjan@linux.intel.com
Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org
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The trailing semicolon is an empty statement that does no operation.
Removing it since it doesn't do anything.
Signed-off-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Partially revert commit 2fa365682943 ("kbuild: soften MODULE_LICENSE
check") so that modpost detects modules that do not have a
MODULE_LICENSE.
Sam's commit also changed the fatal error to a warning, which I am
leaving as is.
This gives advance notice of when a module has no license and will taint
the kernel if the module is loaded.
This produces the following warnings on x86_64 allmodconfig:
MODPOST 6520 modules
WARNING: modpost: missing MODULE_LICENSE() in drivers/auxdisplay/img-ascii-lcd.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-ath79.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-iop.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/accel/kxsd9-i2c.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/adc/qcom-vadc-common.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/mtk-vcodec/mtk-vcodec-common.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/soc_camera/soc_scale_crop.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/mtd/nand/denali_pci.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/net/phy/cortina.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/pinctrl/pxa/pinctrl-pxa2xx.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/power/reset/zx-reboot.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/rpmsg/qcom_glink_native.o
WARNING: modpost: missing MODULE_LICENSE() in drivers/staging/comedi/drivers/ni_atmio.o
WARNING: modpost: missing MODULE_LICENSE() in net/9p/9pnet_xen.o
WARNING: modpost: missing MODULE_LICENSE() in sound/soc/codecs/snd-soc-pcm512x-spi.o
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"Summary of modules changes for the 4.14 merge window:
- minor code cleanups and fixes
- modpost: avoid building modules that have names that exceed the
size of the name field in struct module"
* tag 'modules-for-v4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Remove const attribute from alias for MODULE_DEVICE_TABLE
module: fix ddebug_remove_module()
modpost: abort if module name is too long
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There is code duplication between sec_name() and sech_name(). Simplify
sec_name() by re-using sech_name(). Also, move them up to remove the
forward declaration of sec_name().
Link: http://lkml.kernel.org/r/1502248721-22009-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Module name has a limited length, but currently the build system
allows the build finishing even if the module name is too long.
CC /root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.o
/root/kprobe_example/abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz.mod.c:9:2:
warning: initializer-string for array of chars is too long [enabled by default]
.name = KBUILD_MODNAME,
^
but it's merely a warning.
This patch adds the check of the module name length in modpost and stops
the build properly.
Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Accessing the mod structure (e.g. for mod->name) prior to having completed
check_modstruct_version() can result in writing garbage to the error logs
if the layout of the mod structure loaded from disk doesn't match the
running kernel's mod structure layout. This kind of mismatch will become
much more likely if a kernel is built with different randomization seed
for the struct layout randomization plugin.
Instead, add and use a new modinfo string for logging the module name.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
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The '__unreachable' and '__func_stack_frame_non_standard' sections are
only used at compile time. They're discarded for vmlinux but they
should also be discarded for modules.
Since this is a recurring pattern, prefix the section names with
".discard.". It's a nice convention and vmlinux.lds.h already discards
such sections.
Also remove the 'a' (allocatable) flag from the __unreachable section
since it doesn't make sense for a discarded section.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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