JIRA: https://issues.redhat.com/browse/RHEL-30774
commit d4e48e3dd45017abdd69a19285d197de897ef44f
Author: Alan Maguire <alan.maguire@oracle.com>
Date: Thu Jun 20 10:17:29 2024 +0100
module, bpf: Store BTF base pointer in struct module
...as this will allow split BTF modules with a base BTF
representation (rather than the full vmlinux BTF at time of
BTF encoding) to resolve their references to kernel types in a
way that is more resilient to small changes in kernel types.
This will allow modules that are not built every time the kernel
is to provide more resilient BTF, rather than have it invalidated
every time BTF ids for core kernel types change.
Fields are ordered to avoid holes in struct module.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240620091733.1967885-3-alan.maguire@oracle.com
Signed-off-by: Viktor Malik <vmalik@redhat.com>
commit d81f0d7b8b23ec79f80be602ed6129ded27862e8
Author: Rae Moar <rmoar@google.com>
Date: Wed Dec 13 19:44:17 2023 +0000
kunit: add KUNIT_INIT_TABLE to init linker section
Add KUNIT_INIT_TABLE to the INIT_DATA linker section.
Alter the KUnit macros to create init tests:
kunit_test_init_section_suites
Update lib/kunit/executor.c to run both the suites in KUNIT_TABLE and
KUNIT_INIT_TABLE.
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Rae Moar <rmoar@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
JIRA: https://issues.redhat.com/browse/RHEL-39303
Signed-off-by: Nico Pache <npache@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 8f8cd6c0a43ed637e620bbe45a8d0e0c2f4d5130
Author: Changbin Du <changbin.du@huawei.com>
Date: Tue Feb 27 10:35:46 2024 +0800
modules: wait do_free_init correctly
The synchronization here is to ensure the ordering of freeing of a module
init so that it happens before W+X checking. It is worth noting it is not
that the freeing was not happening, it is just that our sanity checkers
raced against the permission checkers which assume init memory is already
gone.
Commit 1a7b7d9220 ("modules: Use vmalloc special flag") moved calling
do_free_init() into a global workqueue instead of relying on it being
called through call_rcu(..., do_free_init), which used to allowed us call
do_free_init() asynchronously after the end of a subsequent grace period.
The move to a global workqueue broke the gaurantees for code which needed
to be sure the do_free_init() would complete with rcu_barrier(). To fix
this callers which used to rely on rcu_barrier() must now instead use
flush_work(&init_free_wq).
Without this fix, we still could encounter false positive reports in W+X
checking since the rcu_barrier() here can not ensure the ordering now.
Even worse, the rcu_barrier() can introduce significant delay. Eric
Chanudet reported that the rcu_barrier introduces ~0.1s delay on a
PREEMPT_RT kernel.
[ 0.291444] Freeing unused kernel memory: 5568K
[ 0.402442] Run /sbin/init as init process
With this fix, the above delay can be eliminated.
Link: https://lkml.kernel.org/r/20240227023546.2490667-1-changbin.du@huawei.com
Fixes: 1a7b7d9220 ("modules: Use vmalloc special flag")
Signed-off-by: Changbin Du <changbin.du@huawei.com>
Tested-by: Eric Chanudet <echanude@redhat.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Xiaoyi Su <suxiaoyi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
Put back the RHEL-only module-signing patch so distinguishable in RHEL
after move of kernel/module-signing.c to kernel/module/signing.c .
JIRA: https://issues.redhat.com/browse/RHEL-28063
Upstream Status: RHEL-only
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit f17f2c13d613cbeef529b03ca17ae2581b2e6cb8
Author: Kevin Hao <haokexin@gmail.com>
Date: Fri Dec 8 16:29:34 2023 +0800
module: Remove redundant TASK_UNINTERRUPTIBLE
TASK_KILLABLE already includes TASK_UNINTERRUPTIBLE, so there is no
need to add a separate TASK_UNINTERRUPTIBLE.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 17fc8084aa8f9d5235f252fc3978db657dd77e92
Author: Andrea Righi <andrea.righi@canonical.com>
Date: Thu Nov 2 09:19:14 2023 +0100
module/decompress: use kvmalloc() consistently
We consistently switched from kmalloc() to vmalloc() in module
decompression to prevent potential memory allocation failures with large
modules, however vmalloc() is not as memory-efficient and fast as
kmalloc().
Since we don't know in general the size of the workspace required by the
decompression algorithm, it is more reasonable to use kvmalloc()
consistently, also considering that we don't have special memory
requirements here.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit ea0b0bcef4917a2640ecc100c768b8e785784834
Author: Kees Cook <keescook@chromium.org>
Date: Fri Sep 22 10:52:53 2023 -0700
module: Annotate struct module_notes_attrs with __counted_by
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
As found with Coccinelle[1], add __counted_by for struct module_notes_attrs.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 3737df782c740b944912ed93420c57344b1cf864
Author: Andrea Righi <andrea.righi@canonical.com>
Date: Wed Aug 30 17:58:20 2023 +0200
module/decompress: use vmalloc() for gzip decompression workspace
Use a similar approach as commit a419beac4a07 ("module/decompress: use
vmalloc() for zstd decompression workspace") and replace kmalloc() with
vmalloc() also for the gzip module decompression workspace.
In this case the workspace is represented by struct inflate_workspace
that can be fairly large for kmalloc() and it can potentially lead to
allocation errors on certain systems:
$ pahole inflate_workspace
struct inflate_workspace {
struct inflate_state inflate_state; /* 0 9544 */
/* --- cacheline 149 boundary (9536 bytes) was 8 bytes ago --- */
unsigned char working_window[32768]; /* 9544 32768 */
/* size: 42312, cachelines: 662, members: 2 */
/* last cacheline: 8 bytes */
};
Considering that there is no need to use continuous physical memory,
simply switch to vmalloc() to provide a more reliable in-kernel module
decompression.
Fixes: b1ae6dc41eaa ("module: add in-kernel support for decompressing")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 2abcc4b5a64a65a2d2287ba0be5c2871c1552416
Author: James Morse <james.morse@arm.com>
Date: Tue Aug 1 14:54:07 2023 +0000
module: Expose module_init_layout_section()
module_init_layout_section() choses whether the core module loader
considers a section as init or not. This affects the placement of the
exit section when module unloading is disabled. This code will never run,
so it can be free()d once the module has been initialised.
arm and arm64 need to count the number of PLTs they need before applying
relocations based on the section name. The init PLTs are stored separately
so they can be free()d. arm and arm64 both use within_module_init() to
decide which list of PLTs to use when applying the relocation.
Because within_module_init()'s behaviour changes when module unloading
is disabled, both architecture would need to take this into account when
counting the PLTs.
Today neither architecture does this, meaning when module unloading is
disabled there are insufficient PLTs in the init section to load some
modules, resulting in warnings:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
| module_emit_plt_entry+0x184/0x1cc
| apply_relocate_add+0x2bc/0x8e4
| load_module+0xe34/0x1bd4
| init_module_from_file+0x84/0xc0
| __arm64_sys_finit_module+0x1b8/0x27c
| invoke_syscall.constprop.0+0x5c/0x104
| do_el0_svc+0x58/0x160
| el0_svc+0x38/0x110
| el0t_64_sync_handler+0xc0/0xc4
| el0t_64_sync+0x190/0x194
Instead of duplicating module_init_layout_section()s logic, expose it.
Reported-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit c05780ef3c190c2dafbf0be8e65d4f01103ad577
Author: Palmer Dabbelt <palmer@rivosinc.com>
Date: Fri Jul 7 09:00:51 2023 -0700
module: Ignore RISC-V mapping symbols too
RISC-V has an extended form of mapping symbols that we use to encode
the ISA when it changes in the middle of an ELF. This trips up modpost
as a build failure, I haven't yet verified it yet but I believe the
kallsyms difference should result in stacks looking sane again.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit f1962207150c8b602e980616f04b37ea4e64bb9f
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue Jul 4 06:37:32 2023 -0700
module: fix init_module_from_file() error handling
Vegard Nossum pointed out two different problems with the error handling
in init_module_from_file():
(a) the idempotent loading code didn't clean up properly in some error
cases, leaving the on-stack 'struct idempotent' element still in
the hash table
(b) failure to read the module file would nonsensically update the
'invalid_kread_bytes' stat counter with the error value
The first error is quite nasty, in that it can then cause subsequent
idempotent loads of that same file to access stale stack contents of the
previous failure. The case may not happen in any normal situation
(explaining all the "Tested-by's on the original change), and requires
admin privileges, but syzkaller triggers random bad behavior as a
result:
BUG: soft lockup in sys_finit_module
BUG: unable to handle kernel paging request in init_module_from_file
general protection fault in init_module_from_file
INFO: task hung in init_module_from_file
KASAN: out-of-bounds Read in init_module_from_file
KASAN: slab-out-of-bounds Read in init_module_from_file
...
The second error is fairly benign and just leads to nonsensical stats
(and has been around since the debug stats were added).
Vegard also provided a patch for the idempotent loading issue, but I'd
rather re-organize the code and make it more legible using another level
of helper functions than add the usual "goto out" error handling.
Link: https://lore.kernel.org/lkml/20230704100852.23452-1-vegard.nossum@oracle.com/
Fixes: 9b9879fc0327 ("modules: catch concurrent module loads, treat them as idempotent")
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reported-by: syzbot+9c2bdc9d24e4a7abe741@syzkaller.appspotmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 9b9879fc03275ffe0da328cf5b864d9e694167c8
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon May 29 21:39:51 2023 -0400
modules: catch concurrent module loads, treat them as idempotent
This is the new-and-improved attempt at avoiding huge memory load spikes
when the user space boot sequence tries to load hundreds (or even
thousands) of redundant duplicate modules in parallel.
See commit 9828ed3f695a ("module: error out early on concurrent load of
the same module file") for background and an earlier failed attempt that
was reverted.
That earlier attempt just said "concurrently loading the same module is
silly, just open the module file exclusively and return -ETXTBSY if
somebody else is already loading it".
While it is true that concurrent module loads of the same module is
silly, the reason that earlier attempt then failed was that the
concurrently loaded module would often be a prerequisite for another
module.
Thus failing to load the prerequisite would then cause cascading
failures of the other modules, rather than just short-circuiting that
one unnecessary module load.
At the same time, we still really don't want to load the contents of the
same module file hundreds of times, only to then wait for an eventually
successful load, and have everybody else return -EEXIST.
As a result, this takes another approach, and treats concurrent module
loads from the same file as "idempotent" in the inode. So if one module
load is ongoing, we don't start a new one, but instead just wait for the
first one to complete and return the same return value as it did.
So unlike the first attempt, this does not return early: the intent is
not to speed up the boot, but to avoid a thundering herd problem in
allocating memory (both physical and virtual) for a module more than
once.
Also note that this does change behavior: it used to be that when you
had concurrent loads, you'd have one "winner" that would return success,
and everybody else would return -EEXIST.
In contrast, this idempotent logic goes all Oprah on the problem, and
says "You are a winner! And you are a winner! We are ALL winners". But
since there's no possible actual real semantic difference between "you
loaded the module" and "somebody else already loaded the module", this
is more of a feel-good change than an actual honest-to-goodness semantic
change.
Of course, any true Johnny-come-latelies that don't get caught in the
concurrency filter will still return -EEXIST. It's no different from
not even getting a seat at an Oprah taping. That's life.
See the long thread on the kernel mailing list about this all, which
includes some numbers for memory use before and after the patch.
Link: https://lore.kernel.org/lkml/20230524213620.3509138-1-mcgrof@kernel.org/
Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>
Tested-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Rudi Heitbaum <rudi@heitbaum..com>
Tested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 054a73009c22a5fb8bbeee5394980809276bc9fe
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon May 29 20:55:13 2023 -0400
module: split up 'finit_module()' into init_module_from_file() helper
This will simplify the next step, where we can then key off the inode to
do one idempotent module load.
Let's do the obvious re-organization in one step, and then the new code
in another.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
Conflicts:
(1) Dropped patches for check-local-export; that script was temporarily
replacing modpost, but abanadoned and modpost resumed with simpler
addition and-or bug fixes, so skip it here.
(2) Drop ia64 patches since RHEL doesn't support ia64, and didn't apply cleanly.
(3) Made cmd_gensymversions genksyms exec same as cmd_gensymtypes;
cmd_gensymversions appears to be a rhel-ism, and it has no callers/users
under script hierarchy.
commit ddb5cdbafaaad6b99d7007ae1740403124502d03
Author: Masahiro Yamada <masahiroy@kernel.org>
Date: Mon Jun 12 00:50:52 2023 +0900
kbuild: generate KSYMTAB entries by modpost
Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPORT_SYMBOL() is placed in *.c or *.S.
For further cleanups, this commit applies a similar approach to the
entire data structure of EXPORT_SYMBOL().
The EXPORT_SYMBOL() compilation is split into two stages.
When a source file is compiled, EXPORT_SYMBOL() will be converted into
a dummy symbol in the .export_symbol section.
For example,
EXPORT_SYMBOL(foo);
EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE);
will be encoded into the following assembly code:
.section ".export_symbol","a"
__export_symbol_foo:
.asciz "" /* license */
.asciz "" /* name space */
.balign 8
.quad foo /* symbol reference */
.previous
.section ".export_symbol","a"
__export_symbol_bar:
.asciz "GPL" /* license */
.asciz "BAR_NAMESPACE" /* name space */
.balign 8
.quad bar /* symbol reference */
.previous
They are mere markers to tell modpost the name, license, and namespace
of the symbols. They will be dropped from the final vmlinux and modules
because the *(.export_symbol) will go into /DISCARD/ in the linker script.
Then, modpost extracts all the information about EXPORT_SYMBOL() from the
.export_symbol section, and generates the final C code:
KSYMTAB_FUNC(foo, "", "");
KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE");
KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct
kernel_symbol that will be linked to the vmlinux or a module.
With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S
files, providing the following benefits.
[1] Deprecate EXPORT_DATA_SYMBOL()
In the old days, EXPORT_SYMBOL() was only available in C files. To export
a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file.
arch/arm/kernel/armksyms.c is one example written in the classic manner.
Commit 22823ab419 ("EXPORT_SYMBOL() for asm") removed this limitation.
Since then, EXPORT_SYMBOL() can be placed close to the symbol definition
in *.S files. It was a nice improvement.
However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL()
for data objects on some architectures.
In the new approach, modpost checks symbol's type (STT_FUNC or not),
and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly.
There are only two users of EXPORT_DATA_SYMBOL:
EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S)
EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S)
They are transformed as follows and output into .vmlinux.export.c
KSYMTAB_DATA(empty_zero_page, "_gpl", "");
KSYMTAB_DATA(ia64_ivt, "", "");
The other EXPORT_SYMBOL users in ia64 assembly are output as
KSYMTAB_FUNC().
EXPORT_DATA_SYMBOL() is now deprecated.
[2] merge <linux/export.h> and <asm-generic/export.h>
There are two similar header implementations:
include/linux/export.h for .c files
include/asm-generic/export.h for .S files
Ideally, the functionality should be consistent between them, but they
tend to diverge.
Commit 8651ec01da ("module: add support for symbol namespaces.") did
not support the namespace for *.S files.
This commit shifts the essential implementation part to C, which supports
EXPORT_SYMBOL_NS() for *.S files.
<asm/export.h> and <asm-generic/export.h> will remain as a wrapper of
<linux/export.h> for a while.
They will be removed after #include <asm/export.h> directives are all
replaced with #include <linux/export.h>.
[3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit)
When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.
We can do this better now; modpost can selectively emit KSYMTAB entries
that are really used by modules.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit fadb74f9f2f609238070c7ca1b04933dc9400e4a
Author: Lucas De Marchi <lucas.demarchi@intel.com>
Date: Thu Jun 1 14:23:31 2023 -0700
module/decompress: Fix error checking on zstd decompression
While implementing support for in-kernel decompression in kmod,
finit_module() was returning a very suspicious value:
finit_module(3, "", MODULE_INIT_COMPRESSED_FILE) = 18446744072717407296
It turns out the check for module_get_next_page() failing is wrong,
and hence the decompression was not really taking place. Invert
the condition to fix it.
Fixes: 169a58ad824d ("module/decompress: Support zstd in-kernel decompression")
Cc: stable@kernel.org
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit cb0b50b813f6198b7d44ae8e169803440333577a
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue May 9 15:49:02 2023 +0200
module: Remove preempt_disable() from module reference counting.
The preempt_disable() section in module_put() was added in commit
e1783a240f ("module: Use this_cpu_xx to dynamically allocate counters")
while the per-CPU counter were switched to another API. The API requires
that during the RMW operation the CPU remained the same.
This counting API was later replaced with atomic_t in commit
2f35c41f58 ("module: Replace module_ref with atomic_t refcnt")
Since this atomic_t replacement there is no need to keep preemption
disabled while the reference counter is modified.
Remove preempt_disable() from module_put(), __module_get() and
try_module_get().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit d36f6efbe0cb422fe1e4475717d75f3737088832
Author: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Date: Thu Apr 27 22:59:33 2023 -0700
module: Fix use-after-free bug in read_file_mod_stats()
Smatch warns:
kernel/module/stats.c:394 read_file_mod_stats()
warn: passing freed memory 'buf'
We are passing 'buf' to simple_read_from_buffer() after freeing it.
Fix this by changing the order of 'simple_read_from_buffer' and 'kfree'.
Fixes: df3e764d8e5c ("module: add debug stats to help identify memory pressure")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 0b891c83d8c54cb70e186456c2191adb5fd98c56
Author: Arnd Bergmann <arnd@arndb.de>
Date: Sat Apr 29 22:36:04 2023 +0200
module: include internal.h in module/dups.c
Two newly introduced functions are declared in a header that is not
included before the definition, causing a warning with sparse or
'make W=1':
kernel/module/dups.c:118:6: error: no previous prototype for 'kmod_dup_request_exists_wait' [-Werror=missing-prototypes]
118 | bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/module/dups.c:220:6: error: no previous prototype for 'kmod_dup_request_announce' [-Werror=missing-prototypes]
220 | void kmod_dup_request_announce(char *module_name, int ret)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
Add an explicit include to ensure the prototypes match.
Fixes: 8660484ed1cf ("module: add debugging auto-load duplicate module support")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202304141440.DYO4NAzp-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 8660484ed1cf3261e89e0bad94c6395597e87599
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Thu Apr 13 22:28:39 2023 -0700
module: add debugging auto-load duplicate module support
The finit_module() system call can in the worst case use up to more than
twice of a module's size in virtual memory. Duplicate finit_module()
system calls are non fatal, however they unnecessarily strain virtual
memory during bootup and in the worst case can cause a system to fail
to boot. This is only known to currently be an issue on systems with
larger number of CPUs.
To help debug this situation we need to consider the different sources for
finit_module(). Requests from the kernel that rely on module auto-loading,
ie, the kernel's *request_module() API, are one source of calls. Although
modprobe checks to see if a module is already loaded prior to calling
finit_module() there is a small race possible allowing userspace to
trigger multiple modprobe calls racing against modprobe and this not
seeing the module yet loaded.
This adds debugging support to the kernel module auto-loader (*request_module()
calls) to easily detect duplicate module requests. To aid with possible bootup
failure issues incurred by this, it will converge duplicates requests to a
single request. This avoids any possible strain on virtual memory during
bootup which could be incurred by duplicate module autoloading requests.
Folks debugging virtual memory abuse on bootup can and should enable
this to see what pr_warn()s come on, to see if module auto-loading is to
blame for their wores. If they see duplicates they can further debug this
by enabling the module.enable_dups_trace kernel parameter or by enabling
CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS_TRACE.
Current evidence seems to point to only a few duplicates for module
auto-loading. And so the source for other duplicates creating heavy
virtual memory pressure due to larger number of CPUs should becoming
from another place (likely udev).
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit a81b1fc8ea639e03326c1d0dcde041986bc11500
Author: Arnd Bergmann <arnd@arndb.de>
Date: Tue Apr 18 09:17:51 2023 +0200
module: stats: fix invalid_mod_bytes typo
This was caught by randconfig builds but does not show up in
build testing without CONFIG_MODULE_DECOMPRESS:
kernel/module/stats.c: In function 'mod_stat_bump_invalid':
kernel/module/stats.c:229:42: error: 'invalid_mod_byte' undeclared (first use in this function); did you mean 'invalid_mod_bytes'?
229 | atomic_long_add(info->compressed_len, &invalid_mod_byte);
| ^~~~~~~~~~~~~~~~
| invalid_mod_bytes
Fixes: df3e764d8e5c ("module: add debug stats to help identify memory pressure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 9f5cab173e19201eebeaca853ff664a9a269fed0
Author: Tom Rix <trix@redhat.com>
Date: Mon Apr 17 19:09:57 2023 -0400
module: remove use of uninitialized variable len
clang build reports
kernel/module/stats.c:307:34: error: variable
'len' is uninitialized when used here [-Werror,-Wuninitialized]
len = scnprintf(buf + 0, size - len,
^~~
At the start of this sequence, neither the '+ 0', nor the '- len' are needed.
So remove them and fix using 'len' uninitalized.
Fixes: df3e764d8e5c ("module: add debug stats to help identify memory pressure")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 719ccd803ed5bd1ad92b0b46fc095b8fe266827e
Author: Arnd Bergmann <arnd@arndb.de>
Date: Tue Apr 18 00:48:04 2023 +0200
module: fix building stats for 32-bit targets
The new module statistics code mixes 64-bit types and wordsized 'long'
variables, which leads to build failures on 32-bit architectures:
kernel/module/stats.c: In function 'read_file_mod_stats':
kernel/module/stats.c:291:29: error: passing argument 1 of 'atomic64_read' from incompatible pointer type [-Werror=incompatible-pointer-types]
291 | total_size = atomic64_read(&total_mod_size);
x86_64-linux-ld: kernel/module/stats.o: in function `read_file_mod_stats':
stats.c:(.text+0x2b2): undefined reference to `__udivdi3'
To fix this, the code has to use one of the two types consistently.
Change them all to word-size types here.
Fixes: df3e764d8e5c ("module: add debug stats to help identify memory pressure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 635dc38314c75c5727711d896d4c71ec92f6f20b
Author: Arnd Bergmann <arnd@arndb.de>
Date: Tue Apr 18 00:02:46 2023 +0200
module: stats: include uapi/linux/module.h
MODULE_INIT_COMPRESSED_FILE is defined in the uapi header, which
is not included indirectly from the normal linux/module.h, but
has to be pulled in explicitly:
kernel/module/stats.c: In function 'mod_stat_bump_invalid':
kernel/module/stats.c:227:14: error: 'MODULE_INIT_COMPRESSED_FILE' undeclared (first use in this function)
227 | if (flags & MODULE_INIT_COMPRESSED_FILE)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 064f4536d13939b6e8cdb71298ff5d657f4f8caa
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Fri Mar 10 20:48:03 2023 -0800
module: avoid allocation if module is already present and ready
The finit_module() system call can create unnecessary virtual memory
pressure for duplicate modules. This is because load_module() can in
the worse case allocate more than twice the size of a module in virtual
memory. This saves at least a full size of the module in wasted vmalloc
space memory by trying to avoid duplicates as soon as we can validate
the module name in the read module structure.
This can only be an issue if a system is getting hammered with userspace
loading modules. There are two ways to load modules typically on systems,
one is the kernel moduile auto-loading (*request_module*() calls in-kernel)
and the other is things like udev. The auto-loading is in-kernel, but that
pings back to userspace to just call modprobe. We already have a way to
restrict the amount of concurrent kernel auto-loads in a given time, however
that still allows multiple requests for the same module to go through
and force two threads in userspace racing to call modprobe for the same
exact module. Even though libkmod which both modprobe and udev does check
if a module is already loaded prior calling finit_module() races are
still possible and this is clearly evident today when you have multiple
CPUs.
To avoid memory pressure for such stupid cases put a stop gap for them.
The *earliest* we can detect duplicates from the modules side of things
is once we have blessed the module name, sadly after the first vmalloc
allocation. We can check for the module being present *before* a secondary
vmalloc() allocation.
There is a linear relationship between wasted virtual memory bytes and
the number of CPU counts. The reason is that udev ends up racing to call
tons of the same modules for each of the CPUs.
We can see the different linear relationships between wasted virtual
memory and CPU count during after boot in the following graph:
+----------------------------------------------------------------------------+
14GB |-+ + + + + *+ +-|
| **** |
| *** |
| ** |
12GB |-+ ** +-|
| ** |
| ** |
| ** |
| ** |
10GB |-+ ** +-|
| ** |
| ** |
| ** |
8GB |-+ ** +-|
waste | ** ### |
| ** #### |
| ** ####### |
6GB |-+ **** #### +-|
| * #### |
| * #### |
| ***** #### |
4GB |-+ ** #### +-|
| ** #### |
| ** #### |
| ** #### |
2GB |-+ ** ##### +-|
| * #### |
| * #### Before ******* |
| **## + + + + After ####### |
+----------------------------------------------------------------------------+
0 50 100 150 200 250 300
CPUs count
On the y-axis we can see gigabytes of wasted virtual memory during boot
due to duplicate module requests which just end up failing. Trying to
infer the slope this ends up being about ~463 MiB per CPU lost prior
to this patch. After this patch we only loose about ~230 MiB per CPU, for
a total savings of about ~233 MiB per CPU. This is all *just on bootup*!
On a 8vcpu 8 GiB RAM system using kdevops and testing against selftests
kmod.sh -t 0008 I see a saving in the *highest* side of memory
consumption of up to ~ 84 MiB with the Linux kernel selftests kmod
test 0008. With the new stress-ng module test I see a 145 MiB difference
in max memory consumption with 100 ops. The stress-ng module ops tests can be
pretty pathalogical -- it is not realistic, however it was used to
finally successfully reproduce issues which are only reported to happen on
system with over 400 CPUs [0] by just usign 100 ops on a 8vcpu 8 GiB RAM
system. Running out of virtual memory space is no surprise given the
above graph, since at least on x86_64 we're capped at 128 MiB, eventually
we'd hit a series of errors and once can use the above graph to
guestimate when. This of course will vary depending on the features
you have enabled. So for instance, enabling KASAN seems to make this
much worse.
The results with kmod and stress-ng can be observed and visualized below.
The time it takes to run the test is also not affected.
The kmod tests 0008:
The gnuplot is set to a range from 400000 KiB (390 Mib) - 580000 (566 Mib)
given the tests peak around that range.
cat kmod.plot
set term dumb
set output fileout
set yrange [400000:580000]
plot filein with linespoints title "Memory usage (KiB)"
Before:
root@kmod ~ # /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > log-0008-before.txt ^C
root@kmod ~ # sort -n -r log-0008-before.txt | head -1
528732
So ~516.33 MiB
After:
root@kmod ~ # /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > log-0008-after.txt ^C
root@kmod ~ # sort -n -r log-0008-after.txt | head -1
442516
So ~432.14 MiB
That's about 84 ~MiB in savings in the worst case. The graphs:
root@kmod ~ # gnuplot -e "filein='log-0008-before.txt'; fileout='graph-0008-before.txt'" kmod.plot
root@kmod ~ # gnuplot -e "filein='log-0008-after.txt'; fileout='graph-0008-after.txt'" kmod.plot
root@kmod ~ # cat graph-0008-before.txt
580000 +-----------------------------------------------------------------+
| + + + + + + + |
560000 |-+ Memory usage (KiB) ***A***-|
| |
540000 |-+ +-|
| |
| *A *AA*AA*A*AA *A*AA A*A*A *AA*A*AA*A A |
520000 |-+A*A*AA *AA*A *A*AA*A*AA *A*A A *A+-|
|*A |
500000 |-+ +-|
| |
480000 |-+ +-|
| |
460000 |-+ +-|
| |
| |
440000 |-+ +-|
| |
420000 |-+ +-|
| + + + + + + + |
400000 +-----------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
root@kmod ~ # cat graph-0008-after.txt
580000 +-----------------------------------------------------------------+
| + + + + + + + |
560000 |-+ Memory usage (KiB) ***A***-|
| |
540000 |-+ +-|
| |
| |
520000 |-+ +-|
| |
500000 |-+ +-|
| |
480000 |-+ +-|
| |
460000 |-+ +-|
| |
| *A *A*A |
440000 |-+A*A*AA*A A A*A*AA A*A*AA*A*AA*A*AA*A*AA*AA*A*AA*A*AA-|
|*A *A*AA*A |
420000 |-+ +-|
| + + + + + + + |
400000 +-----------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
The stress-ng module tests:
This is used to run the test to try to reproduce the vmap issues
reported by David:
echo 0 > /proc/sys/vm/oom_dump_tasks
./stress-ng --module 100 --module-name xfs
Prior to this commit:
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > baseline-stress-ng.txt
root@kmod ~ # sort -n -r baseline-stress-ng.txt | head -1
5046456
After this commit:
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > after-stress-ng.txt
root@kmod ~ # sort -n -r after-stress-ng.txt | head -1
4896972
5046456 - 4896972
149484
149484/1024
145.98046875000000000000
So this commit using stress-ng reveals saving about 145 MiB in memory
using 100 ops from stress-ng which reproduced the vmap issue reported.
cat kmod.plot
set term dumb
set output fileout
set yrange [4700000:5070000]
plot filein with linespoints title "Memory usage (KiB)"
root@kmod ~ # gnuplot -e "filein='baseline-stress-ng.txt'; fileout='graph-stress-ng-before.txt'" kmod-simple-stress-ng.plot
root@kmod ~ # gnuplot -e "filein='after-stress-ng.txt'; fileout='graph-stress-ng-after.txt'" kmod-simple-stress-ng.plot
root@kmod ~ # cat graph-stress-ng-before.txt
+---------------------------------------------------------------+
5.05e+06 |-+ + A + + + + + + +-|
| * Memory usage (KiB) ***A*** |
| * A |
5e+06 |-+ ** ** +-|
| ** * * A |
4.95e+06 |-+ * * A * A* +-|
| * * A A * * * * A |
| * * * * * * *A * * * A * |
4.9e+06 |-+ * * * A*A * A*AA*A A *A **A **A*A *+-|
| A A*A A * A * * A A * A * ** |
| * ** ** * * * * * * * |
4.85e+06 |-+ A A A ** * * ** *-|
| * * * * ** * |
| * A * * * * |
4.8e+06 |-+ * * * A A-|
| * * * |
4.75e+06 |-+ * * * +-|
| * ** |
| * + + + + + + ** + |
4.7e+06 +---------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
root@kmod ~ # cat graph-stress-ng-after.txt
+---------------------------------------------------------------+
5.05e+06 |-+ + + + + + + + +-|
| Memory usage (KiB) ***A*** |
| |
5e+06 |-+ +-|
| |
4.95e+06 |-+ +-|
| |
| |
4.9e+06 |-+ *AA +-|
| A*AA*A*A A A*AA*AA*A*AA*A A A A*A *AA*A*A A A*AA*AA |
| * * ** * * * ** * *** * |
4.85e+06 |-+* *** * * * * *** A * * +-|
| * A * * ** * * A * * |
| * * * * ** * * |
4.8e+06 |-+* * * A * * * +-|
| * * * A * * |
4.75e+06 |-* * * * * +-|
| * * * * * |
| * + * *+ + + + + * *+ |
4.7e+06 +---------------------------------------------------------------+
0 5 10 15 20 25 30 35 40
[0] https://lkml.kernel.org/r/20221013180518.217405-1-david@redhat.com
Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
Conflicts:
Adding RHEL-only MODULE_STATS set to n for now. Possibly
add in future -debug kernels, to be determined.
Add rest of commit(s) to enable clean backport for further commits.
commit df3e764d8e5cd416efee29e0de3c93917dff5d33
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Tue Mar 28 20:03:19 2023 -0700
module: add debug stats to help identify memory pressure
Loading modules with finit_module() can end up using vmalloc(), vmap()
and vmalloc() again, for a total of up to 3 separate allocations in the
worst case for a single module. We always kernel_read*() the module,
that's a vmalloc(). Then vmap() is used for the module decompression,
and if so the last read buffer is freed as we use the now decompressed
module buffer to stuff data into our copy module. The last allocation is
specific to each architectures but pretty much that's generally a series
of vmalloc() calls or a variation of vmalloc to handle ELF sections with
special permissions.
Evaluation with new stress-ng module support [1] with just 100 ops
is proving that you can end up using GiBs of data easily even with all
care we have in the kernel and userspace today in trying to not load modules
which are already loaded. 100 ops seems to resemble the sort of pressure a
system with about 400 CPUs can create on module loading. Although issues
relating to duplicate module requests due to each CPU inucurring a new
module reuest is silly and some of these are being fixed, we currently lack
proper tooling to help diagnose easily what happened, when it happened
and who likely is to blame -- userspace or kernel module autoloading.
Provide an initial set of stats which use debugfs to let us easily scrape
post-boot information about failed loads. This sort of information can
be used on production worklaods to try to optimize *avoiding* redundant
memory pressure using finit_module().
There's a few examples that can be provided:
A 255 vCPU system without the next patch in this series applied:
Startup finished in 19.143s (kernel) + 7.078s (userspace) = 26.221s
graphical.target reached after 6.988s in userspace
And 13.58 GiB of virtual memory space lost due to failed module loading:
root@big ~ # cat /sys/kernel/debug/modules/stats
Mods ever loaded 67
Mods failed on kread 0
Mods failed on decompress 0
Mods failed on becoming 0
Mods failed on load 1411
Total module size 11464704
Total mod text size 4194304
Failed kread bytes 0
Failed decompress bytes 0
Failed becoming bytes 0
Failed kmod bytes 14588526272
Virtual mem wasted bytes 14588526272
Average mod size 171115
Average mod text size 62602
Average fail load bytes 10339140
Duplicate failed modules:
module-name How-many-times Reason
kvm_intel 249 Load
kvm 249 Load
irqbypass 8 Load
crct10dif_pclmul 128 Load
ghash_clmulni_intel 27 Load
sha512_ssse3 50 Load
sha512_generic 200 Load
aesni_intel 249 Load
crypto_simd 41 Load
cryptd 131 Load
evdev 2 Load
serio_raw 1 Load
virtio_pci 3 Load
nvme 3 Load
nvme_core 3 Load
virtio_pci_legacy_dev 3 Load
virtio_pci_modern_dev 3 Load
t10_pi 3 Load
virtio 3 Load
crc32_pclmul 6 Load
crc64_rocksoft 3 Load
crc32c_intel 40 Load
virtio_ring 3 Load
crc64 3 Load
The following screen shot, of a simple 8vcpu 8 GiB KVM guest with the
next patch in this series applied, shows 226.53 MiB are wasted in virtual
memory allocations which due to duplicate module requests during boot.
It also shows an average module memory size of 167.10 KiB and an an
average module .text + .init.text size of 61.13 KiB. The end shows all
modules which were detected as duplicate requests and whether or not
they failed early after just the first kernel_read*() call or late after
we've already allocated the private space for the module in
layout_and_allocate(). A system with module decompression would reveal
more wasted virtual memory space.
We should put effort now into identifying the source of these duplicate
module requests and trimming these down as much possible. Larger systems
will obviously show much more wasted virtual memory allocations.
root@kmod ~ # cat /sys/kernel/debug/modules/stats
Mods ever loaded 67
Mods failed on kread 0
Mods failed on decompress 0
Mods failed on becoming 83
Mods failed on load 16
Total module size 11464704
Total mod text size 4194304
Failed kread bytes 0
Failed decompress bytes 0
Failed becoming bytes 228959096
Failed kmod bytes 8578080
Virtual mem wasted bytes 237537176
Average mod size 171115
Average mod text size 62602
Avg fail becoming bytes 2758544
Average fail load bytes 536130
Duplicate failed modules:
module-name How-many-times Reason
kvm_intel 7 Becoming
kvm 7 Becoming
irqbypass 6 Becoming & Load
crct10dif_pclmul 7 Becoming & Load
ghash_clmulni_intel 7 Becoming & Load
sha512_ssse3 6 Becoming & Load
sha512_generic 7 Becoming & Load
aesni_intel 7 Becoming
crypto_simd 7 Becoming & Load
cryptd 3 Becoming & Load
evdev 1 Becoming
serio_raw 1 Becoming
nvme 3 Becoming
nvme_core 3 Becoming
t10_pi 3 Becoming
virtio_pci 3 Becoming
crc32_pclmul 6 Becoming & Load
crc64_rocksoft 3 Becoming
crc32c_intel 3 Becoming
virtio_pci_modern_dev 2 Becoming
virtio_pci_legacy_dev 1 Becoming
crc64 2 Becoming
virtio 2 Becoming
virtio_ring 2 Becoming
[0] https://github.com/ColinIanKing/stress-ng.git
[1] echo 0 > /proc/sys/vm/oom_dump_tasks
./stress-ng --module 100 --module-name xfs
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit f71afa6a420111da90657fe999a8e32c42d5c7d6
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Fri Mar 10 20:05:52 2023 -0800
module: extract patient module check into helper
The patient module check inside add_unformed_module() is large
enough as we need it. It is a bit hard to read too, so just
move it to a helper and do the inverse checks first to help
shift the code and make it easier to read. The new helper then
is module_patient_check_exists().
To make this work we need to mvoe the finished_loading() up,
we do that without making any functional changes to that routine.
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
Conflicts: RHEL9 does not have upstrema 48380368dec148 which
changed DEFINE_SEMAPHORE to take a number argument.
Implement the RHEL9 single arg version that open-codes
the initialization.
commit 25a1b5b518f4336bff934ac8348da6c57158363a
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Fri Mar 24 18:38:00 2023 -0700
modules/kmod: replace implementation with a semaphore
Simplify the concurrency delimiter we use for kmod with the semaphore.
I had used the kmod strategy to try to implement a similar concurrency
delimiter for the kernel_read*() calls from the finit_module() path
so to reduce vmalloc() memory pressure. That effort didn't provide yet
conclusive results, but one thing that became clear is we can use
the suggested alternative solution with semaphores which Linus hinted
at instead of using the atomic / wait strategy.
I've stress tested this with kmod test 0008:
time /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
And I get only a *slight* delay. That delay however is small, a few
seconds for a full test loop run that runs 150 times, for about ~30-40
seconds. The small delay is worth the simplfication IMHO.
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 430bb0d1c3376c988982f14bcbe71f917c89e1ab
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Tue Apr 4 18:52:47 2023 -0700
module: fix kmemleak annotations for non init ELF sections
Commit ac3b43283923 ("module: replace module_layout with module_memory")
reworked the way to handle memory allocations to make it clearer. But it
lost in translation how we handled kmemleak_ignore() or kmemleak_not_leak()
for different ELF sections.
Fix this and clarify the comments a bit more. Contrary to the old way
of using kmemleak_ignore() for init.* ELF sections we stick now only to
kmemleak_not_leak() as per suggestion by Catalin Marinas so to avoid
any false positives and simplify the code.
Fixes: ac3b43283923 ("module: replace module_layout with module_memory")
Reported-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 0a3bf86092c38f7b72c56c6901c78dd302411307
Author: Tiezhu Yang <yangtiezhu@loongson.cn>
Date: Fri Mar 31 17:15:53 2023 +0800
module: Ignore L0 and rename is_arm_mapping_symbol()
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>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
Conflict: Slight context diff but patch changes are the same.
commit 987d2e0aaa55de40938435be760aa96428470fd6
Author: Tiezhu Yang <yangtiezhu@loongson.cn>
Date: Fri Mar 31 17:15:52 2023 +0800
module: Move is_arm_mapping_symbol() to module_symbol.h
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>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 87e5b1e8f257023ac5c4d2b8f07716a7f3dcc8ea
Author: Tiezhu Yang <yangtiezhu@loongson.cn>
Date: Fri Mar 31 17:15:51 2023 +0800
module: Sync code of is_arm_mapping_symbol()
After commit 2e3a10a155 ("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>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 33c951f62920d144ca89daa0560180a49afb6f1e
Author: Jim Cromie <jim.cromie@gmail.com>
Date: Tue Mar 21 19:36:23 2023 -0600
module: already_uses() - reduce pr_debug output volume
already_uses() is unnecessarily chatty.
`modprobe i915` yields 491 messages like:
[ 64.108744] i915 uses drm!
This is a normal situation, and isn't worth all the log entries.
NOTE: I've preserved the "does not use %s" messages, which happens
less often, but does happen. Its not clear to me what it tells a
reader, or what info might improve the pr_debug's utility.
[ 6847.584999] main:already_uses:569: amdgpu does not use ttm!
[ 6847.585001] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585014] main:already_uses:569: amdgpu does not use drm!
[ 6847.585016] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585024] main:already_uses:569: amdgpu does not use drm_display_helper!
[ 6847.585025] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585084] main:already_uses:569: amdgpu does not use drm_kms_helper!
[ 6847.585086] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585175] main:already_uses:569: amdgpu does not use drm_buddy!
[ 6847.585176] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585202] main:already_uses:569: amdgpu does not use i2c_algo_bit!
[ 6847.585204] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585249] main:already_uses:569: amdgpu does not use gpu_sched!
[ 6847.585250] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585314] main:already_uses:569: amdgpu does not use video!
[ 6847.585315] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585409] main:already_uses:569: amdgpu does not use iommu_v2!
[ 6847.585410] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585816] main:already_uses:569: amdgpu does not use drm_ttm_helper!
[ 6847.585818] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6848.762268] dyndbg: add-module: amdgpu.2533 sites
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 66a2301edf313d630c2ece4f3721c5b3402653ee
Author: Jim Cromie <jim.cromie@gmail.com>
Date: Tue Mar 21 19:36:22 2023 -0600
module: add section-size to move_module pr_debug
move_module() pr_debug's "Final section addresses for $modname".
Add section addresses to the message, for anyone looking at these.
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit b10addf37bbcaee66672eb54c15532266c8daea6
Author: Jim Cromie <jim.cromie@gmail.com>
Date: Tue Mar 21 19:36:21 2023 -0600
module: add symbol-name to pr_debug Absolute symbol
The pr_debug("Absolute symbol" ..) reports value, (which is usually
0), but not the name, which is more informative. So add it.
no functional changes
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 6ed81802d4d1b037ad2d1657511ff0c2e9aeda14
Author: Jim Cromie <jim.cromie@gmail.com>
Date: Tue Mar 21 19:36:20 2023 -0600
module: in layout_sections, move_module: add the modname
layout_sections() and move_module() each issue ~50 messages for each
module loaded. Add mod-name into their 2 header lines, to help the
reader find his module.
no functional changes.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
Conflict: Dropped MAINTAINERS hunk because it wouldn't apply cleanly
and not needed.
commit 25be451aa4c0e9a96c59a626ab0e93d5cb7f6f48
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:35:42 2023 -0700
module: fold usermode helper kmod into modules directory
The kernel/kmod.c is already only built if we enabled modules, so
just stuff it under kernel/module/kmod.c and unify the MAINTAINERS
file for it.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 3d40bb903ed1f654707d34bdd61ee2c332000e4b
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:35:41 2023 -0700
module: merge remnants of setup_load_info() to elf validation
The setup_load_info() was actually had ELF validation checks of its
own. To later cache useful variables as an secondary step just means
looping again over the ELF sections we just validated. We can simply
keep tabs of the key sections of interest as we validate the module
ELF section in one swoop, so do that and merge the two routines
together.
Expand a bit on the documentation / intent / goals.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 1bb49db9919a4d4186cba288930e7026d8f7ec96
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:35:40 2023 -0700
module: move more elf validity checks to elf_validity_check()
The symbol and strings section validation currently happen in
setup_load_info() but since they are also doing validity checks
move this to elf_validity_check().
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit c7ee8aebf6c0588c0aab76538aff395c3abf811c
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:35:39 2023 -0700
module: add stop-grap sanity check on module memcpy()
The integrity of the struct module we load is important, and although
our ELF validator already checks that the module section must match
struct module, add a stop-gap check before we memcpy() the final minted
module. This also makes those inspecting the code what the goal is.
While at it, clarify the goal behind updating the sh_addr address.
The current comment is pretty misleading.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 46752820f9abc013b6bd8172562b642376723313
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:35:38 2023 -0700
module: add sanity check for ELF module section
The ELF ".gnu.linkonce.this_module" section is special, it is what we
use to construct the struct module __this_module, which THIS_MODULE
points to. When userspace loads a module we always deal first with a
copy of the userspace buffer, and twiddle with the userspace copy's
version of the struct module. Eventually we allocate memory to do a
memcpy() of that struct module, under the assumption that the module
size is right. But we have no validity checks against the size or
the requirements for the section.
Add some validity checks for the special module section early and while
at it, cache the module section index early, so we don't have to do that
later.
While at it, just move over the assigment of the info->mod to make the
code clearer. The validity checker also adds an explicit size check to
ensure the module section size matches the kernel's run time size for
sizeof(struct module). This should prevent sloppy loads of modules
which are built today *without* actually increasing the size of
the struct module. A developer today can for example expand the size
of struct module, rebuild a directoroy 'make fs/xfs/' for example and
then try to insmode the driver there. That module would in effect have
an incorrect size. This new size check would put a stop gap against such
mistakes.
This also makes the entire goal of ".gnu.linkonce.this_module" pretty
clear. Before this patch verification of the goal / intent required some
Indian Jones whips, torches and cleaning up big old spider webs.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 419e1a20f7bdef5380fde5ed73f05c98c28a598b
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:27:46 2023 -0700
module: rename check_module_license_and_versions() to check_export_symbol_versions()
This makes the routine easier to understand what the check its checking for.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 72f08b3cc631f4ebcaa9f373d18fc0b877fb6458
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:27:45 2023 -0700
module: converge taint work together
Converge on a compromise: so long as we have a module hit our linked
list of modules we taint. That is, the module was about to become live.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit c3bbf62ebf8c9e87cea875cfa146f44f46af4145
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:27:44 2023 -0700
module: move signature taint to module_augment_kernel_taints()
Just move the signature taint into the helper:
module_augment_kernel_taints()
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit a12b94511cf36855cd731c16005bd535e2007552
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:27:43 2023 -0700
module: move tainting until after a module hits our linked list
It is silly to have taints spread out all over, we can just compromise
and add them if the module ever hit our linked list. Our sanity checkers
should just prevent crappy drivers / bogus ELF modules / etc and kconfig
options should be enough to let you *not* load things you don't want.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-28063
commit 437c1f9cc61fd37829eaf12d8ae2f7dcc5dddce0
Author: Luis Chamberlain <mcgrof@kernel.org>
Date: Sun Mar 19 14:27:42 2023 -0700
module: split taint adding with info checking
check_modinfo() actually does two things:
a) sanity checks, some of which are fatal, and so we
prevent the user from completing trying to load a module
b) taints the kernel
The taints are pretty heavy handed because we're tainting the kernel
*before* we ever even get to load the module into the modules linked
list. That is, it it can fail for other reasons later as we review the
module's structure.
But this commit makes no functional changes, it just makes the intent
clearer and splits the code up where needed to make that happen.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Donald Dutile <ddutile@redhat.com>
Viktor Malik
Nico Pache
Donald Dutile