This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
The linker script scripts/module.lds.S specifies that all input
__klp_objects sections should be consolidated into an output section of
the same name, and start/stop symbols should be created to enable
scripts/livepatch/init.c to locate this data.
This start/stop pattern is not ideal for modules because the symbols are
created even if no __klp_objects input sections are present.
Consequently, a dummy __klp_objects section also appears in the
resulting module. This unnecessarily pollutes non-livepatch modules.
Instead, since modules are relocatable files, the usual method for
locating consolidated data in a module is to read its section table.
This approach avoids the aforementioned problem.
The klp_modinfo already stores a copy of the entire section table with
the final addresses. Introduce a helper function that
scripts/livepatch/init.c can call to obtain the location of the
__klp_objects section from this data.
Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Link: https://patch.msgid.link/20260123102825.3521961-2-petr.pavlu@suse.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Pull livepatching updates from Petr Mladek:
- Support both paths where tracefs is typically mounted in selftests
- Make old_sympos 0 and 1 equal. They both are valid when there is only
one symbol with the given name.
* tag 'livepatching-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
selftests: livepatch: use canonical ftrace path
livepatch: Match old_sympos 0 and 1 in klp_find_func()
When there is only one function of the same name, old_sympos of 0 and 1
are logically identical. Match them in klp_find_func().
This is to avoid a corner case with different toolchain behavior.
In this specific issue, two versions of kpatch-build were used to
build livepatch for the same kernel. One assigns old_sympos == 0 for
unique local functions, the other assigns old_sympos == 1 for unique
local functions. Both versions work fine by themselves. (PS: This
behavior change was introduced in a downstream version of kpatch-build.
This change does not exist in upstream kpatch-build.)
However, during livepatch upgrade (with the replace flag set) from a
patch built with one version of kpatch-build to the same fix built with
the other version of kpatch-build, livepatching fails with errors like:
[ 14.218706] sysfs: cannot create duplicate filename 'xxx/somefunc,1'
...
[ 14.219466] Call Trace:
[ 14.219468] <TASK>
[ 14.219469] dump_stack_lvl+0x47/0x60
[ 14.219474] sysfs_warn_dup.cold+0x17/0x27
[ 14.219476] sysfs_create_dir_ns+0x95/0xb0
[ 14.219479] kobject_add_internal+0x9e/0x260
[ 14.219483] kobject_add+0x68/0x80
[ 14.219485] ? kstrdup+0x3c/0xa0
[ 14.219486] klp_enable_patch+0x320/0x830
[ 14.219488] patch_init+0x443/0x1000 [ccc_0_6]
[ 14.219491] ? 0xffffffffa05eb000
[ 14.219492] do_one_initcall+0x2e/0x190
[ 14.219494] do_init_module+0x67/0x270
[ 14.219496] init_module_from_file+0x75/0xa0
[ 14.219499] idempotent_init_module+0x15a/0x240
[ 14.219501] __x64_sys_finit_module+0x61/0xc0
[ 14.219503] do_syscall_64+0x5b/0x160
[ 14.219505] entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 14.219507] RIP: 0033:0x7f545a4bd96d
...
[ 14.219516] kobject: kobject_add_internal failed for somefunc,1 with
-EEXIST, don't try to register things with the same name ...
This happens because klp_find_func() thinks somefunc with old_sympos==0
is not the same as somefunc with old_sympos==1, and klp_add_object_nops
adds another xxx/func,1 to the list of functions to patch.
Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
[pmladek@suse.com: Fixed some typos.]
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
In preparation for introducing klp-build, add a new CONFIG_KLP_BUILD
option. The initial version will only be supported on x86-64.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add a new klp diff subcommand which performs a binary diff between two
object files and extracts changed functions into a new object which can
then be linked into a livepatch module.
This builds on concepts from the longstanding out-of-tree kpatch [1]
project which began in 2012 and has been used for many years to generate
livepatch modules for production kernels. However, this is a complete
rewrite which incorporates hard-earned lessons from 12+ years of
maintaining kpatch.
Key improvements compared to kpatch-build:
- Integrated with objtool: Leverages objtool's existing control-flow
graph analysis to help detect changed functions.
- Works on vmlinux.o: Supports late-linked objects, making it
compatible with LTO, IBT, and similar.
- Simplified code base: ~3k fewer lines of code.
- Upstream: No more out-of-tree #ifdef hacks, far less cruft.
- Cleaner internals: Vastly simplified logic for symbol/section/reloc
inclusion and special section extraction.
- Robust __LINE__ macro handling: Avoids false positive binary diffs
caused by the __LINE__ macro by introducing a fix-patch-lines script
(coming in a later patch) which injects #line directives into the
source .patch to preserve the original line numbers at compile time.
Note the end result of this subcommand is not yet functionally complete.
Livepatch needs some ELF magic which linkers don't like:
- Two relocation sections (.rela*, .klp.rela*) for the same text
section.
- Use of SHN_LIVEPATCH to mark livepatch symbols.
Unfortunately linkers tend to mangle such things. To work around that,
klp diff generates a linker-compliant intermediate binary which encodes
the relevant KLP section/reloc/symbol metadata.
After module linking, a klp post-link step (coming soon) will clean up
the mess and convert the linked .ko into a fully compliant livepatch
module.
Note this subcommand requires the diffed binaries to have been compiled
with -ffunction-sections and -fdata-sections, and processed with
'objtool --checksum'. Those constraints will be handled by a klp-build
script introduced in a later patch.
Without '-ffunction-sections -fdata-sections', reliable object diffing
would be infeasible due to toolchain limitations:
- For intra-file+intra-section references, the compiler might
occasionally generated hard-coded instruction offsets instead of
relocations.
- Section-symbol-based references can be ambiguous:
- Overlapping or zero-length symbols create ambiguity as to which
symbol is being referenced.
- A reference to the end of a symbol (e.g., checking array bounds)
can be misinterpreted as a reference to the next symbol, or vice
versa.
A potential future alternative to '-ffunction-sections -fdata-sections'
would be to introduce a toolchain option that forces symbol-based
(non-section) relocations.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Add the section number and reloc index to relocation error messages to
help find the faulty relocation.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Pull modules updates from Petr Pavlu:
- Use RCU instead of RCU-sched
The mix of rcu_read_lock(), rcu_read_lock_sched() and
preempt_disable() in the module code and its users has
been replaced with just rcu_read_lock()
- The rest of changes are smaller fixes and updates
* tag 'modules-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux: (32 commits)
MAINTAINERS: Update the MODULE SUPPORT section
module: Remove unnecessary size argument when calling strscpy()
module: Replace deprecated strncpy() with strscpy()
params: Annotate struct module_param_attrs with __counted_by()
bug: Use RCU instead RCU-sched to protect module_bug_list.
static_call: Use RCU in all users of __module_text_address().
kprobes: Use RCU in all users of __module_text_address().
bpf: Use RCU in all users of __module_text_address().
jump_label: Use RCU in all users of __module_text_address().
jump_label: Use RCU in all users of __module_address().
x86: Use RCU in all users of __module_address().
cfi: Use RCU while invoking __module_address().
powerpc/ftrace: Use RCU in all users of __module_text_address().
LoongArch: ftrace: Use RCU in all users of __module_text_address().
LoongArch/orc: Use RCU in all users of __module_address().
arm64: module: Use RCU in all users of __module_text_address().
ARM: module: Use RCU in all users of __module_text_address().
module: Use RCU in all users of __module_text_address().
module: Use RCU in all users of __module_address().
module: Use RCU in search_module_extables().
...
Add "stack_order" sysfs attribute which holds the order in which a live
patch module was loaded into the system. A user can then determine an
active live patched version of a function.
cat /sys/kernel/livepatch/livepatch_1/stack_order -> 1
means that livepatch_1 is the first live patch applied
cat /sys/kernel/livepatch/livepatch_module/stack_order -> N
means that livepatch_module is the Nth live patch applied
Suggested-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Miroslav Benes <mbenes@suse.cz>
Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Wardenjohn <zhangwarden@gmail.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20241008014856.3729-2-zhangwarden@gmail.com
[pmladek@suse.com: Updated kernel version and date in the ABI documentation.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
There are situations when it might make sense to combine livepatches
with and without the atomic replace on the same system. For example,
the livepatch without the atomic replace might provide a hotfix
or extra tuning.
Managing livepatches on such systems might be challenging. And the
information which of the installed livepatches do not use the atomic
replace would be useful.
Add new sysfs interface 'replace'. It works as follows:
$ cat /sys/kernel/livepatch/livepatch-non_replace/replace
0
$ cat /sys/kernel/livepatch/livepatch-replace/replace
1
[ commit log improved by Petr ]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20240625151123.2750-2-laoar.shao@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull scheduler updates from Ingo Molnar:
- Allow unprivileged PSI poll()ing
- Fix performance regression introduced by mm_cid
- Improve livepatch stalls by adding livepatch task switching to
cond_resched(). This resolves livepatching busy-loop stalls with
certain CPU-bound kthreads
- Improve sched_move_task() performance on autogroup configs
- On core-scheduling CPUs, avoid selecting throttled tasks to run
- Misc cleanups, fixes and improvements
* tag 'sched-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/clock: Fix local_clock() before sched_clock_init()
sched/rt: Fix bad task migration for rt tasks
sched: Fix performance regression introduced by mm_cid
sched/core: Make sched_dynamic_mutex static
sched/psi: Allow unprivileged polling of N*2s period
sched/psi: Extract update_triggers side effect
sched/psi: Rename existing poll members in preparation
sched/psi: Rearrange polling code in preparation
sched/fair: Fix inaccurate tally of ttwu_move_affine
vhost: Fix livepatch timeouts in vhost_worker()
livepatch,sched: Add livepatch task switching to cond_resched()
livepatch: Skip task_call_func() for current task
livepatch: Convert stack entries array to percpu
sched: Interleave cfs bandwidth timers for improved single thread performance at low utilization
sched/core: Reduce cost of sched_move_task when config autogroup
sched/core: Avoid selecting the task that is throttled to run when core-sched enable
sched/topology: Make sched_energy_mutex,update static
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 entries array in klp_check_stack() is static local because it's too
big to be reasonably allocated on the stack. Serialized access is
enforced by the klp_mutex.
In preparation for calling klp_check_stack() without the mutex (from
cond_resched), convert it to a percpu variable.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230313233346.kayh4t2lpicjkpsv@treble
Linus Torvalds
Kees Cook
Petr PavluandJosh Poimboeuf
Song LiuandPetr Mladek
Peter Zijlstra
Sebastian Andrzej SiewiorandPetr Pavlu
Yafang ShaoandPetr Mladek
WardenjohnandPetr Mladek
Zheng YejianandPetr Mladek
Zhen LeiandLuis Chamberlain
Thomas WeißschuhandPetr Mladek