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with commit '7878c231dae0 ("slab: remove /proc/slab_allocators")'
lookup_symbol_attrs usage is removed.
Thus removing redundant API.
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
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
8b41fc4454e ("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
...
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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 c17a2538704f ("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>
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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>
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After commit 2e3a10a1551d ("ARM: avoid ARM binutils leaking ELF local
symbols") and commit d6b732666a1b ("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>
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Artem reported suspicious RCU usage [1]. The reason is that verifier
calls find_kallsyms_symbol_value with preemption enabled which will
trigger suspicious RCU usage warning in rcu_dereference_sched call.
Disabling preemption in find_kallsyms_symbol_value and adding
__find_kallsyms_symbol_value function.
Fixes: 31bf1dbccfb0 ("bpf: Fix attaching fentry/fexit/fmod_ret/lsm to modules")
Reported-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/bpf/20230403220254.2191240-1-jolsa@kernel.org
[1] https://lore.kernel.org/bpf/ZBrPMkv8YVRiWwCR@samus.usersys.redhat.com/
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{module_}kallsyms_on_each_symbol()
The parameter 'struct module *' in the hook function associated with
{module_}kallsyms_on_each_symbol() is no longer used. Delete it.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:
1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
obvious how these data are used (are they RO, RX, or RW?)
Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:
MOD_TEXT,
MOD_DATA,
MOD_RODATA,
MOD_RO_AFTER_INIT,
MOD_INIT_TEXT,
MOD_INIT_DATA,
MOD_INIT_RODATA,
and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.
Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.
module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.
Signed-off-by: Song Liu <song@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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Currently we traverse all symbols of all modules to find the specified
function for the specified module. But in reality, we just need to find
the given module and then traverse all the symbols in it.
Let's add a new parameter 'const char *modname' to function
module_kallsyms_on_each_symbol(), then we can compare the module names
directly in this function and call hook 'fn' after matching. If 'modname'
is NULL, the symbols of all modules are still traversed for compatibility
with other usage cases.
Phase1: mod1-->mod2..(subsequent modules do not need to be compared)
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Phase2: -->f1-->f2-->f3
Assuming that there are m modules, each module has n symbols on average,
then the time complexity is reduced from O(m * n) to O(m) + O(n).
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230116101009.23694-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Making module_kallsyms_on_each_symbol generally available, so it
can be used outside CONFIG_LIVEPATCH option in following changes.
Rather than adding another ifdef option let's make the function
generally available (when CONFIG_KALLSYMS and CONFIG_MODULES
options are defined).
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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module_kallsyms_lookup_name() has several exit conditions but
can't return immediately due to preempt_disable().
Refactor module_kallsyms_lookup_name() to allow returning from
anywhere, and reduce depth.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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Checkpatch reports following errors:
ERROR: do not use assignment in if condition
+ if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
ERROR: do not use assignment in if condition
+ if ((mod = find_module_all(name, colon - name, false)) != NULL)
ERROR: do not use assignment in if condition
+ if ((ret = find_kallsyms_symbol_value(mod, name)) != 0)
ERROR: do not initialise globals to 0
+int modules_disabled = 0;
Fix them.
The following one has to remain, because the condition has to be evaluated
multiple times by the macro wait_event_interruptible_timeout().
ERROR: do not use assignment in if condition
+ if (wait_event_interruptible_timeout(module_wq,
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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The commit 08126db5ff73 ("module: kallsyms: Fix suspicious rcu usage")
under PREEMPT_RT=y, disabling preemption introduced an unbounded
latency since the loop is not fixed. This change caused a regression
since previously preemption was not disabled and we would dereference
RCU-protected pointers explicitly. That being said, these pointers
cannot change.
Before kallsyms-specific data is prepared/or set-up, we ensure that
the unformed module is known to be unique i.e. does not already exist
(see load_module()). Therefore, we can fix this by using the common and
more appropriate RCU flavour as this section of code can be safely
preempted.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 08126db5ff73 ("module: kallsyms: Fix suspicious rcu usage")
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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The commit 91fb02f31505 ("module: Move kallsyms support into a separate
file") changed from using strlcpy() to using strscpy() which created a
buffer overflow. That happened because:
1) an incorrect value was passed as the buffer length
2) strscpy() (unlike strlcpy()) may copy beyond the length of the
input string when copying word-by-word.
The assumption was that because it was already known that the strings
being copied would fit in the space available, it was not necessary
to correctly set the buffer length. strscpy() breaks that assumption
because although it will not touch bytes beyond the given buffer length
it may write bytes beyond the input string length when writing
word-by-word.
The result of the buffer overflow is to corrupt the symbol type
information that follows. e.g.
$ sudo cat -v /proc/kallsyms | grep '\^' | head
ffffffffc0615000 ^@ rfcomm_session_get [rfcomm]
ffffffffc061c060 ^@ session_list [rfcomm]
ffffffffc06150d0 ^@ rfcomm_send_frame [rfcomm]
ffffffffc0615130 ^@ rfcomm_make_uih [rfcomm]
ffffffffc07ed58d ^@ bnep_exit [bnep]
ffffffffc07ec000 ^@ bnep_rx_control [bnep]
ffffffffc07ec1a0 ^@ bnep_session [bnep]
ffffffffc07e7000 ^@ input_leds_event [input_leds]
ffffffffc07e9000 ^@ input_leds_handler [input_leds]
ffffffffc07e7010 ^@ input_leds_disconnect [input_leds]
Notably, the null bytes (represented above by ^@) can confuse tools.
Fix by correcting the buffer length.
Fixes: 91fb02f31505 ("module: Move kallsyms support into a separate file")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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In order to allow separation of data from text, add another layout,
called data_layout. For architectures requesting separation of text
and data, only text will go in core_layout and data will go in
data_layout.
For architectures which keep text and data together, make data_layout
an alias of core_layout, that way data_layout can be used for all
data manipulations, regardless of whether data is in core_layout or
data_layout.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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debug_align() was added by commit 84e1c6bb38eb ("x86: Add RO/NX
protection for loadable kernel modules")
At that time the config item was CONFIG_DEBUG_SET_MODULE_RONX.
But nowadays it has changed to CONFIG_STRICT_MODULE_RWX and
debug_align() is confusing because it has nothing to do with
DEBUG.
Rename it strict_align()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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No functional change.
The purpose of this patch is to address the various Sparse warnings
due to the incorrect dereference/or access of an __rcu pointer.
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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No functional change.
This patch migrates kallsyms code out of core module
code kernel/module/kallsyms.c
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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