There is no distinction between TEXT_TO_ANY_EXIT and DATA_TO_ANY_EXIT.
Just merge them.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
This check is unneeded. Without it, sec_name() will returns the null
string "", then section_mismatch() will return immediately.
Anyway, special section indices rarely appear in these loops.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
r_offset/r_addend holds the offset address from/to which a symbol is
referenced. It is unclear unless you are familiar with ELF.
Rename them to faddr, taddr, respectively. The prefix 'f' means 'from',
't' means 'to'.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
find_tosym() takes 'sym' and stores the return value to another
variable 'to'. You can use the same variable because we want to
replace the original one when appropriate.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
This reverts commit a4d26f1a09.
The variable 'fromsym' never starts with ".L" since commit 87e5b1e8f2
("module: Sync code of is_arm_mapping_symbol()").
In other words, Pattern 6 is now dead code.
Previously, the .LANCHOR1 hid the symbols listed in Pattern 2.
87e5b1e8f2 provided a better solution.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
find_elf_symbol() and find_elf_symbol2() are not good names.
Rename them to find_tosym(), find_fromsym(), respectively.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
find_elf_symbol2() converts the section index to the section name,
then compares the two strings in each iteration. This is slow.
It is faster to compare the section indices (i.e. integers) directly.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
default_mismatch_handler() does not need to compute 'tosec' because
it is calculated by the caller.
Pass it down to default_mismatch_handler() instead of calling
sec_name() twice.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Merging these two reduces several lines of code. The extable section
mismatch is already distinguished by EXTABLE_TO_NON_TEXT.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
SHF_EXECINSTR is a bit flag (#define SHF_EXECINSTR 0x4).
Compare the masked flag to '!= 0'.
There is no good reason to stop modpost immediately even if a special
section index is given. You will get a section mismatch error anyway.
Also, change the return type to bool.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
report_sec_mismatch() and default_mismatch_handler() are small enough
to be merged together.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Collect relevant code into one place to clarify all the cases are
covered by 'if () ... else if ... else ...'.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
This is the last user of get_pretty_name() - it is just used to
distinguish whether the symbol is a function or not. It is not
valuable information.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
report_extable_warnings() prints "from" in a pretty form, but we know
it is always located in the __ex_table section, i.e. a collection of
struct exception_table_entry.
It is very likely to fail to get the symbol name and ends up with
meaningless message:
... in reference from the (unknown reference) (unknown) to ...
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
find_extable_entry_size() is completely broken. It has awesome comments
about how to calculate sizeof(struct exception_table_entry).
It was based on these assumptions:
- struct exception_table_entry has two fields
- both of the fields have the same size
Then, we came up with this equation:
(offset of the second field) * 2 == (size of struct)
It was true for all architectures when commit 52dc0595d5 ("modpost:
handle relocations mismatch in __ex_table.") was applied.
Our mathematics broke when commit 548acf1923 ("x86/mm: Expand the
exception table logic to allow new handling options") introduced the
third field.
Now, the definition of exception_table_entry is highly arch-dependent.
For x86, sizeof(struct exception_table_entry) is apparently 12, but
find_extable_entry_size() sets extable_entry_size to 8.
I could fix it, but I do not see much value in this code.
extable_entry_size is used just for selecting a slightly different
error message.
If the first field ("insn") references to a non-executable section,
The relocation at %s+0x%lx references
section "%s" which is not executable, IOW
it is not possible for the kernel to fault
at that address. Something is seriously wrong
and should be fixed.
If the second field ("fixup") references to a non-executable section,
The relocation at %s+0x%lx references
section "%s" which is not executable, IOW
the kernel will fault if it ever tries to
jump to it. Something is seriously wrong
and should be fixed.
Merge the two error messages rather than adding even more complexity.
Change fatal() to error() to make it continue running and catch more
possible errors.
Fixes: 548acf1923 ("x86/mm: Expand the exception table logic to allow new handling options")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The section mismatch check relies on the relocation entries.
For REL, the addend value is implicit, so we need some code to compute
it. Currently, EM_386, EM_ARM, and EM_MIPS are supported. This commit
makes sure we covered all the cases.
I believe the other architectures use RELA, where the explicit r_addend
field exists.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull module updates from Luis Chamberlain:
"The summary of the changes for this pull requests is:
- Song Liu's new struct module_memory replacement
- Nick Alcock's MODULE_LICENSE() removal for non-modules
- My cleanups and enhancements to reduce the areas where we vmalloc
module memory for duplicates, and the respective debug code which
proves the remaining vmalloc pressure comes from userspace.
Most of the changes have been in linux-next for quite some time except
the minor fixes I made to check if a module was already loaded prior
to allocating the final module memory with vmalloc and the respective
debug code it introduces to help clarify the issue. Although the
functional change is small it is rather safe as it can only *help*
reduce vmalloc space for duplicates and is confirmed to fix a bootup
issue with over 400 CPUs with KASAN enabled. I don't expect stable
kernels to pick up that fix as the cleanups would have also had to
have been picked up. Folks on larger CPU systems with modules will
want to just upgrade if vmalloc space has been an issue on bootup.
Given the size of this request, here's some more elaborate details:
The functional change change in this pull request is the very first
patch from Song Liu which replaces the 'struct module_layout' with a
new 'struct module_memory'. The old data structure tried to put
together all types of supported module memory types in one data
structure, the new one abstracts the differences in memory types in a
module to allow each one to provide their own set of details. This
paves the way in the future so we can deal with them in a cleaner way.
If you look at changes they also provide a nice cleanup of how we
handle these different memory areas in a module. This change has been
in linux-next since before the merge window opened for v6.3 so to
provide more than a full kernel cycle of testing. It's a good thing as
quite a bit of fixes have been found for it.
Jason Baron then made dynamic debug a first class citizen module user
by using module notifier callbacks to allocate / remove module
specific dynamic debug information.
Nick Alcock has done quite a bit of work cross-tree to remove module
license tags from things which cannot possibly be module at my request
so to:
a) help him with his longer term tooling goals which require a
deterministic evaluation if a piece a symbol code could ever be
part of a module or not. But quite recently it is has been made
clear that tooling is not the only one that would benefit.
Disambiguating symbols also helps efforts such as live patching,
kprobes and BPF, but for other reasons and R&D on this area is
active with no clear solution in sight.
b) help us inch closer to the now generally accepted long term goal
of automating all the MODULE_LICENSE() tags from SPDX license tags
In so far as a) is concerned, although module license tags are a no-op
for non-modules, tools which would want create a mapping of possible
modules can only rely on the module license tag after the commit
8b41fc4454 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf").
Nick has been working on this *for years* and AFAICT I was the only
one to suggest two alternatives to this approach for tooling. The
complexity in one of my suggested approaches lies in that we'd need a
possible-obj-m and a could-be-module which would check if the object
being built is part of any kconfig build which could ever lead to it
being part of a module, and if so define a new define
-DPOSSIBLE_MODULE [0].
A more obvious yet theoretical approach I've suggested would be to
have a tristate in kconfig imply the same new -DPOSSIBLE_MODULE as
well but that means getting kconfig symbol names mapping to modules
always, and I don't think that's the case today. I am not aware of
Nick or anyone exploring either of these options. Quite recently Josh
Poimboeuf has pointed out that live patching, kprobes and BPF would
benefit from resolving some part of the disambiguation as well but for
other reasons. The function granularity KASLR (fgkaslr) patches were
mentioned but Joe Lawrence has clarified this effort has been dropped
with no clear solution in sight [1].
In the meantime removing module license tags from code which could
never be modules is welcomed for both objectives mentioned above. Some
developers have also welcomed these changes as it has helped clarify
when a module was never possible and they forgot to clean this up, and
so you'll see quite a bit of Nick's patches in other pull requests for
this merge window. I just picked up the stragglers after rc3. LWN has
good coverage on the motivation behind this work [2] and the typical
cross-tree issues he ran into along the way. The only concrete blocker
issue he ran into was that we should not remove the MODULE_LICENSE()
tags from files which have no SPDX tags yet, even if they can never be
modules. Nick ended up giving up on his efforts due to having to do
this vetting and backlash he ran into from folks who really did *not
understand* the core of the issue nor were providing any alternative /
guidance. I've gone through his changes and dropped the patches which
dropped the module license tags where an SPDX license tag was missing,
it only consisted of 11 drivers. To see if a pull request deals with a
file which lacks SPDX tags you can just use:
./scripts/spdxcheck.py -f \
$(git diff --name-only commid-id | xargs echo)
You'll see a core module file in this pull request for the above, but
that's not related to his changes. WE just need to add the SPDX
license tag for the kernel/module/kmod.c file in the future but it
demonstrates the effectiveness of the script.
Most of Nick's changes were spread out through different trees, and I
just picked up the slack after rc3 for the last kernel was out. Those
changes have been in linux-next for over two weeks.
The cleanups, debug code I added and final fix I added for modules
were motivated by David Hildenbrand's report of boot failing on a
systems with over 400 CPUs when KASAN was enabled due to running out
of virtual memory space. Although the functional change only consists
of 3 lines in the patch "module: avoid allocation if module is already
present and ready", proving that this was the best we can do on the
modules side took quite a bit of effort and new debug code.
The initial cleanups I did on the modules side of things has been in
linux-next since around rc3 of the last kernel, the actual final fix
for and debug code however have only been in linux-next for about a
week or so but I think it is worth getting that code in for this merge
window as it does help fix / prove / evaluate the issues reported with
larger number of CPUs. Userspace is not yet fixed as it is taking a
bit of time for folks to understand the crux of the issue and find a
proper resolution. Worst come to worst, I have a kludge-of-concept [3]
of how to make kernel_read*() calls for modules unique / converge
them, but I'm currently inclined to just see if userspace can fix this
instead"
Link: https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/ [0]
Link: https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com [1]
Link: https://lwn.net/Articles/927569/ [2]
Link: https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org [3]
* tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (121 commits)
module: add debugging auto-load duplicate module support
module: stats: fix invalid_mod_bytes typo
module: remove use of uninitialized variable len
module: fix building stats for 32-bit targets
module: stats: include uapi/linux/module.h
module: avoid allocation if module is already present and ready
module: add debug stats to help identify memory pressure
module: extract patient module check into helper
modules/kmod: replace implementation with a semaphore
Change DEFINE_SEMAPHORE() to take a number argument
module: fix kmemleak annotations for non init ELF sections
module: Ignore L0 and rename is_arm_mapping_symbol()
module: Move is_arm_mapping_symbol() to module_symbol.h
module: Sync code of is_arm_mapping_symbol()
scripts/gdb: use mem instead of core_layout to get the module address
interconnect: remove module-related code
interconnect: remove MODULE_LICENSE in non-modules
zswap: remove MODULE_LICENSE in non-modules
zpool: remove MODULE_LICENSE in non-modules
x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules
...
The L0 symbol is generated when build module on LoongArch, ignore it in
modpost and when looking at module symbols, otherwise we can not see the
expected call trace.
Now is_arm_mapping_symbol() is not only for ARM, in order to reflect the
reality, rename is_arm_mapping_symbol() to is_mapping_symbol().
This is related with commit c17a253870 ("mksysmap: Fix the mismatch of
'L0' symbols in System.map").
(1) Simple test case
[loongson@linux hello]$ cat hello.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
static void test_func(void)
{
pr_info("This is a test\n");
dump_stack();
}
static int __init hello_init(void)
{
pr_warn("Hello, world\n");
test_func();
return 0;
}
static void __exit hello_exit(void)
{
pr_warn("Goodbye\n");
}
module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
[loongson@linux hello]$ cat Makefile
obj-m:=hello.o
ccflags-y += -g -Og
all:
make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) modules
clean:
make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) clean
(2) Test environment
system: LoongArch CLFS 5.5
https://github.com/sunhaiyong1978/CLFS-for-LoongArch/releases/tag/5.0
It needs to update grub to avoid booting error "invalid magic number".
kernel: 6.3-rc1 with loongson3_defconfig + CONFIG_DYNAMIC_FTRACE=y
(3) Test result
Without this patch:
[root@linux hello]# insmod hello.ko
[root@linux hello]# dmesg
...
Hello, world
This is a test
...
Call Trace:
[<9000000000223728>] show_stack+0x68/0x18c
[<90000000013374cc>] dump_stack_lvl+0x60/0x88
[<ffff800002050028>] L0\x01+0x20/0x2c [hello]
[<ffff800002058028>] L0\x01+0x20/0x30 [hello]
[<900000000022097c>] do_one_initcall+0x88/0x288
[<90000000002df890>] do_init_module+0x54/0x200
[<90000000002e1e18>] __do_sys_finit_module+0xc4/0x114
[<90000000013382e8>] do_syscall+0x7c/0x94
[<9000000000221e3c>] handle_syscall+0xbc/0x158
With this patch:
[root@linux hello]# insmod hello.ko
[root@linux hello]# dmesg
...
Hello, world
This is a test
...
Call Trace:
[<9000000000223728>] show_stack+0x68/0x18c
[<90000000013374cc>] dump_stack_lvl+0x60/0x88
[<ffff800002050028>] test_func+0x28/0x34 [hello]
[<ffff800002058028>] hello_init+0x28/0x38 [hello]
[<900000000022097c>] do_one_initcall+0x88/0x288
[<90000000002df890>] do_init_module+0x54/0x200
[<90000000002e1e18>] __do_sys_finit_module+0xc4/0x114
[<90000000013382e8>] do_syscall+0x7c/0x94
[<9000000000221e3c>] handle_syscall+0xbc/0x158
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Tested-by: Youling Tang <tangyouling@loongson.cn> # for LoongArch
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
In order to avoid duplicated code, move is_arm_mapping_symbol() to
include/linux/module_symbol.h, then remove is_arm_mapping_symbol()
in the other places.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
After commit 2e3a10a155 ("ARM: avoid ARM binutils leaking ELF local
symbols") and commit d6b732666a ("modpost: fix undefined behavior of
is_arm_mapping_symbol()"), many differences of is_arm_mapping_symbol()
exist in kernel/module/kallsyms.c and scripts/mod/modpost.c, just sync
the code to keep consistent.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
modpost now reads CRCs from .*.cmd files, parsing them using strtol().
This is inconsistent with its parsing of Module.symvers and with their
definition as *unsigned* 32-bit values.
strtol() clamps values to [LONG_MIN, LONG_MAX], and when building on a
32-bit system this changes all CRCs >= 0x80000000 to be 0x7fffffff.
Change extract_crcs_for_object() to use strtoul() instead.
Cc: stable@vger.kernel.org
Fixes: f292d875d0 ("modpost: extract symbol versions from *.cmd files")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Masahiro Yamada
Linus Torvalds
Tiezhu YangandLuis Chamberlain
Greg Kroah-Hartman
Nipun GuptaandGreg Kroah-Hartman
Ben HutchingsandMasahiro Yamada