Pull locking updates from Ingo Molnar:
"Lock debugging:
- Implement compiler-driven static analysis locking context checking,
using the upcoming Clang 22 compiler's context analysis features
(Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context tracking
Sparse warnings, the overwhelming majority of which are false
positives. On an allmodconfig kernel the number of false positive
context tracking Sparse warnings grows to over 5,200... On the plus
side of the balance actual locking bugs found by Sparse context
analysis is also rather ... sparse: I found only 3 such commits in
the last 3 years. So the rate of false positives and the
maintenance overhead is rather high and there appears to be no
active policy in place to achieve a zero-warnings baseline to move
the annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive in
trying to find bugs, at least in principle. Plus it has a different
model to enabling it: it's enabled subsystem by subsystem, which
results in zero warnings on all relevant kernel builds (as far as
our testing managed to cover it). Which allowed us to enable it by
default, similar to other compiler warnings, with the expectation
that there are no warnings going forward. This enforces a
zero-warnings baseline on clang-22+ builds (Which are still limited
in distribution, admittedly)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more subsystems
and drivers enabling the feature. Context tracking can be enabled
for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional function
calls
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John
Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
Duberstein)"
* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
rcu: Mark lockdep_assert_rcu_helper() __always_inline
compiler-context-analysis: Remove __assume_ctx_lock from initializers
tomoyo: Use scoped init guard
crypto: Use scoped init guard
kcov: Use scoped init guard
compiler-context-analysis: Introduce scoped init guards
cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
seqlock: fix scoped_seqlock_read kernel-doc
tools: Update context analysis macros in compiler_types.h
rust: sync: Replace `kernel::c_str!` with C-Strings
rust: sync: Inline various lock related methods
rust: helpers: Move #define __rust_helper out of atomic.c
rust: wait: Add __rust_helper to helpers
rust: time: Add __rust_helper to helpers
rust: task: Add __rust_helper to helpers
rust: sync: Add __rust_helper to helpers
rust: refcount: Add __rust_helper to helpers
rust: rcu: Add __rust_helper to helpers
rust: processor: Add __rust_helper to helpers
...
Enable context analysis for crypto subsystem.
This demonstrates a larger conversion to use Clang's context
analysis. The benefit is additional static checking of locking rules,
along with better documentation.
Note the use of the __acquire_ret macro how to define an API where a
function returns a pointer to an object (struct scomp_scratch) with a
lock held. Additionally, the analysis only resolves aliases where the
analysis unambiguously sees that a variable was not reassigned after
initialization, requiring minor code changes.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-36-elver@google.com
Replace the for loop with a call to crypto_unregister_scomps(). Return
'ret' immediately and remove the goto statement to simplify the error
handling code. No functional changes.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add the __maybe_unused attribute to the crypto_scomp_show() definition
and remove the now-unnecessary forward declaration.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As chaining has been removed, all that remains of REQ_CHAIN is
just virtual address support. Rename it before the reintroduction
of batching creates confusion.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Commit ddd0a42671 only increments scomp_scratch_users when it was 0,
causing a panic when using ipcomp:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 619 Comm: ping Tainted: G N 6.15.0-rc3-net-00032-ga79be02bba5c #41 PREEMPT(full)
Tainted: [N]=TEST
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
RIP: 0010:inflate_fast+0x5a2/0x1b90
[...]
Call Trace:
<IRQ>
zlib_inflate+0x2d60/0x6620
deflate_sdecompress+0x166/0x350
scomp_acomp_comp_decomp+0x45f/0xa10
scomp_acomp_decompress+0x21/0x120
acomp_do_req_chain+0x3e5/0x4e0
ipcomp_input+0x212/0x550
xfrm_input+0x2de2/0x72f0
[...]
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: disabled
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Instead, let's keep the old increment, and decrement back to 0 if the
scratch allocation fails.
Fixes: ddd0a42671 ("crypto: scompress - Fix scratch allocation failure handling")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Merge crypto tree to pick up scompress off-by-one patch. The
merge resolution is non-trivial as the dst handling code has been
moved in front of the src.
Fix off-by-one bug in the last page calculation for src and dst.
Reported-by: Nhat Pham <nphamcs@gmail.com>
Fixes: 2d3553ecb4 ("crypto: scomp - Remove support for some non-trivial SG lists")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
If the bit CRYPTO_ALG_DUP_FIRST is set, an algorithm will be
duplicated by kmemdup before registration. This is inteded for
hardware-based algorithms that may be unplugged at will.
Do not use this if the algorithm data structure is embedded in a
bigger data structure. Perform the duplication in the driver
instead.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Rather than storing the folio as is and handling it later, convert
it to a scatterlist right away.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In order to use scomp_free_streams to free the partially allocted
streams in the allocation error path, move the alg->stream assignment
to the beginning. Also check for error pointers in scomp_free_streams
before freeing the ctx.
Finally set alg->stream to NULL to not break subsequent attempts
to allocate the streams.
Fixes: 3d72ad46a2 ("crypto: acomp - Move stream management into scomp layer")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Co-developed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Co-developed-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As the scomp streams are freed when an algorithm is unregistered,
it is possible that the algorithm has never been used at all (e.g.,
an algorithm that does not have a self-test). So test whether the
streams exist before freeing them.
Reported-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Fixes: 3d72ad46a2 ("crypto: acomp - Move stream management into scomp layer")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As deflate has been converted over to acomp, and cavium zip has been
removed, there are no longer any scomp algorithms that can be used
by IPsec.
Since IPsec was the only user of the dst scratch buffer, remove it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Move the dynamic stream allocation code into acomp and make it
available as a helper for acomp algorithms.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Per-cpu buffers can be wasteful when the number of CPUs is large,
especially if the buffer itself is likely to never be used. Reduce
such wastage by only allocating them on first use of a particular
CPU.
On start-up allocate a single buffer on the first possible CPU.
For every other CPU a work struct will be scheduled on first use
to allocate the buffer for that CPU. Until the allocation succeeds
simply use the first CPU's buffer which is protected under a spin
lock.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
If the scratch allocation fails, all subsequent allocations will
silently succeed without actually allocating anything. Fix this
by only incrementing users when the allocation succeeds.
Fixes: 6a8487a1f2 ("crypto: scompress - defer allocation of scratch buffer to first use")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
For many users, it's easier to supply a folio rather than an SG
list since they already have them. Add support for folios to the
acomp interface.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As the only user of acomp/scomp uses a trivial single-page SG
list, remove support for everything else in preprataion for the
addition of virtual address support.
However, keep support for non-trivial source SG lists as that
user is currently jumping through hoops in order to linearise
the source data.
Limit the source SG linearisation buffer to a single page as
that user never goes over that. The only other potential user
is also unlikely to exceed that (IPComp) and it can easily do
its own linearisation if necessary.
Also keep the destination SG linearisation for IPComp.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Disable BH when taking per-cpu spin locks. This isn't an issue
right now because the only user zswap calls scomp from process
context. However, if scomp is called from softirq context the
spin lock may dead-lock.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Rather than allocating the stream memory in the request object,
move it into a per-cpu buffer managed by scomp. This takes the
stress off the user from having to manage large request objects
and setting up their own per-cpu buffers in order to do so.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Linus Torvalds
Marco ElverandPeter Zijlstra
Thorsten BlumandHerbert Xu
David HildenbrandandAndrew Morton
Sabrina DubrocaandHerbert Xu