uuid_kunit currently exercises only guid_parse() and uuid_parse() (plus
their invalid-input paths). The four random generators exported from
lib/uuid.c -- generate_random_uuid(), generate_random_guid(), uuid_gen()
and guid_gen() -- have no direct kunit coverage.
Random output cannot be compared against a fixed expected value, but RFC
4122 section 4.4 specifies two invariants that any version-4 random
UUID/GUID must satisfy:
- version 4 in the high nibble of the version byte
(byte 6 in the wire uuid_t layout, byte 7 in the byte-swapped
guid_t layout);
- variant DCE 1.1 (binary 10x) in the high bits of byte 8.
Add four test cases that invoke each generator several times and verify
these bit patterns hold. The same checks catch a regression in either the
mask/OR sequence in the generators or the layout constants. Run the loop
a handful of times to cover the small but non-zero chance that an unmasked
random byte happens to satisfy the version/variant pattern by accident on
a single call.
Link: https://lore.kernel.org/20260516120915.40544-1-sozdayvek@gmail.com
Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <david@davidgow.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "cleanup the RAID6 P/Q library", v3.
This series cleans up the RAID6 P/Q library to match the recent updates to
the RAID 5 XOR library and other CRC/crypto libraries. This includes
providing properly documented external interfaces, hiding the internals,
using static_call instead of indirect calls and turning the user space
test suite into an in-kernel kunit test which is also extended to improve
coverage.
Note that this changes registration so that non-priority algorithms are
not registered, which greatly helps with the benchmark time at boot time.
I'd like to encourage all architecture maintainers to see if they can
further optimized this by registering as few as possible algorithms when
there is a clear benefit in optimized or more unrolled implementations.
This patch (of 18):
Currently the raid6 code can be compiled as userspace code to run the test
suite. Convert that to be a kunit case with minimal changes to avoid
mutating global state so that we can drop this requirement.
Note that this is not a good kunit test case yet and will need a lot more
work, but that is deferred until the raid6 code is moved to it's new
place, which is easier if the userspace makefile doesn't need adjustments
for the new location first.
Link: https://lore.kernel.org/20260518051804.462141-1-hch@lst.de
Link: https://lore.kernel.org/20260518051804.462141-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org> # kunit only on arm64
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Nan <linan122@huawei.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Song Liu <song@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Improve the overall code quality of lib/bug.c by:
- Reformatting the main documentation block to follow the standard
kernel multi-line comment style.
- Replacing 'unsigned' with the preferred 'unsigned int'.
- Converting legacy printk() calls to modern pr_warn() and pr_info()
macros to include proper facility levels and satisfy checkpatch.
Link: https://lore.kernel.org/20260504201607.56932-1-lucasp.linux@gmail.com
Signed-off-by: Lucas Poupeau <lucasp.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "lib/base64: decode fixes", v2.
Two small fixes for lib/base64.c:
1. base64_decode() writes a decoded byte to the output buffer before
validating the input in the trailing-bytes path. Move the validity
checks before any writes so dst is untouched on invalid input.
2. The @padding kernel-doc for base64_decode() was copy-pasted from
base64_encode() and describes the wrong direction.
This patch (of 2):
The trailing-bytes path in base64_decode() writes a decoded byte to the
output buffer before checking whether the input characters are valid. If
the input is malformed, garbage is written to dst before the function
returns -1.
Move the validity checks before any writes so the output buffer is left
untouched on invalid input.
Link: https://lore.kernel.org/20260324223210.47676-1-objecting@objecting.org
Link: https://lore.kernel.org/20260324223210.47676-2-objecting@objecting.org
Fixes: 9c7d3cf94d ("lib/base64: rework encode/decode for speed and stricter validation")
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull debugobjects fix from Ingo Molnar::
- Fix debugobjects regression on -rt kernels: don't fill the pool
(which uses a coarse lock) if ->pi_blocked_on, because that messes up
the priority inheritance of callers
* tag 'core-urgent-2026-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
debugobjects: Do not fill_pool() if pi_blocked_on
Pull misc fixes from Andrew Morton:
"14 hotfixes. 9 are for MM. 10 are cc:stable and the remainder are for
post-7.1 issues or aren't deemed suitable for backporting.
There's a two-patch MAINTAINERS series from Mike Rapoport which
updates us for the new KEXEC/KDUMP/crash/LUO/etc arrangements. And
another two-patch series from Muchun Song to fix a couple of
memory-hotplug issues. Otherwise singletons, please see the changelogs
for details"
* tag 'mm-hotfixes-stable-2026-05-18-21-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/memory: fix spurious warning when unmapping device-private/exclusive pages
mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()
drivers/base/memory: fix memory block reference leak in poison accounting
mm/memory_hotplug: fix memory block reference leak on remove
lib: kunit_iov_iter: fix test fail on powerpc
mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free
MAINTAINERS: add kexec@ list to LIVE UPDATE ENTRY
MAINTAINERS: add tree for KDUMP and KEXEC
selftests/mm: run_vmtests.sh: fix destructive tests invocation
scripts/gdb: slab: update field names of struct kmem_cache
scripts/gdb: mm: cast untyped symbols in x86_page_ops
mm/damon: fix damos_stat tracepoint format for sz_applied
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
mm/migrate_device: fix spinlock leak in migrate_vma_insert_huge_pmd_page
Pull timer fix from Ingo Molnar:
- Fix potential garbage reads in the vDSO gettimeofday code
(Thomas Weißschuh)
* tag 'timers-urgent-2026-05-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
vdso/gettimeofday: Reload sequence counter after switch to time page in do_aux()
Pull crypto fixes from Herbert Xu:
- Fix potential dead-lock in rhashtable when used by xattr
- Avoid calling kvfree on atomic path in rhashtable
* tag 'v7.1-p4' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
rhashtable: Add bucket_table_free_atomic() helper
mm/slab: Add kvfree_atomic() helper
rhashtable: drop ht->mutex in rhashtable_free_and_destroy()
After switching to the real data pages, the sequence counter needs to be
reloaded from there. The code using vdso_read_begin_timens() assumed
this worked by 'continue' jumping to the *beginning* of the do-while
retry loop. However the 'continue' jumps to the *end* of said loop,
evaluating the exit condition. If the data page has a sequence counter
of '1' it will match the one from the time namespace page and prematurely
exit the retry loop. This would result in garbage returned to the caller.
Reload the sequence counter after switching the pages by using an inner
while loop again, which will loop at most once.
The loop generates slightly better code than an explicit reload through
'seq = vdso_read_begin()'.
Fixes: ed78b7b2c5 ("vdso/gettimeofday: Add a helper to read the sequence lock of a time namespace aware clock")
Reported-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Link: https://patch.msgid.link/20260422-vdso-aux-timens-loop-v1-1-e2dd8c7164cc@linutronix.de
Closes: https://lore.kernel.org/lkml/CANiDSCsOy0P1if-gJZqOM5pTJ0RDcwVfru1B7KFbTOEMqjPKJw@mail.gmail.com/
Pull probes fixes from Masami Hiramatsu:
- kprobes: skip non-symbol addresses in kprobe_add_ksym_blacklist()
Since the ftrace adds its NOPs at .kprobes.text section (which stores
an array), a wrong entry is added when loading a module which uses
"__kprobes" attribute.
To solve this, add "notrace" to __kprobes functions
- test_kprobes: clear kprobes between test runs
Clear all kprobes in the test program after running a test set,
because Kunit test can run several times
- fprobe: Fix unregister_fprobe() to wait for RCU grace period
Since the fprobe data structure is removed with hlist_del_rcu(), it
should wait for the RCU grace period. If the caller waits for RCU, we
can use the async variant (e.g. eBPF)
* tag 'probes-fixes-v7.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
fprobe: Fix unregister_fprobe() to wait for RCU grace period
test_kprobes: clear kprobes between test runs
kprobes: skip non-symbol addresses in kprobe_add_ksym_blacklist()
Pull kunit fixes from Shuah Khan:
"Fix to decouple KUNIT_DEBUGFS and KUNIT_ALL_TESTS options and fix
KUNIT_DEBUGFS dependencies so it depends on DEBUG_FS without which it
will not be useful"
* tag 'linux_kselftest-kunit-fixes-7.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
kunit: config: KUNIT_DEBUGFS should depend on DEBUG_FS
kunit: config: Enable KUNIT_DEBUGFS by default
Running the kprobes sanity tests twice makes all tests fail and
eventually crashes the kernel.
[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run
...
# Totals: pass:5 fail:0 skip:0 total:5
ok 1 kprobes_test
[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run
...
# test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64
Expected 0 == register_kprobe(&kp), but
register_kprobe(&kp) == -22 (0xffffffffffffffea)
...
Unable to handle kernel paging request ...
The testsuite defines several kprobes and kretprobes as static variables
that are preserved across test runs.
After register_kprobe and unregister_kprobe, a kprobe contains some
leftover data that must be cleared before the kprobe can be registered
again. The tests are setting symbol_name to define the probe location.
Address and flags must be cleared.
The existing code clears some of the probes between subsequent tests, but
not between two test runs. The leftover data from a previous test run
makes the registrations fail in the next run.
Move the cleanups for all kprobes into kprobes_test_init, this function
is called before each single test (including the first test of a test
run).
Link: https://lore.kernel.org/all/20260507134615.1010905-1-martin@kaiser.cx/
Fixes: e44e81c5b9 ("kprobes: convert tests to kunit")
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Pull fbdev fixes from Helge Deller:
"Four small patches for fbdev, of which two are important: One fixes
the bitmap font generation and the other prevents a possible
use-after-free in udlfb:
- Fix rotating fonts by 180 degrees (Thomas Zimmermann)
- Drop duplicate include of linux/module.h in fb_defio (Chen Ni)
- Add vm_ops in udlfb to prevent use-after-free (Rajat Gupta)
- ipu-v3: clean up kernel-doc warnings (Randy Dunlap)"
* tag 'fbdev-for-7.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free
lib/fonts: Fix bit position when rotating by 180 degrees
fbdev: defio: Remove duplicate include of linux/module.h
fbdev: ipu-v3: clean up kernel-doc warnings
rhashtable_insert_rehash() allocates a new bucket table
with GFP_ATOMIC, as it is called from an RCU read-side
critical section.
If rhashtable_rehash_attach() then fails, the new table
is freed via kvfree(). This is unsafe, since kvfree() may
fall back to vfree() for vmalloc-backed allocations, which
can sleep and trigger:
BUG: sleeping function called from invalid context
Add bucket_table_free_atomic(), which uses kvfree_atomic()
so the table can be freed safely from non-sleeping context.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
rhashtable_free_and_destroy() is a single-shot teardown routine:
cancel_work_sync() has already quiesced the deferred rehash worker, and
the function's documented contract requires the caller to guarantee no
other concurrent access to the rhashtable. Under those conditions
ht->mutex is not protecting anything -- taking it is a leftover from
the original teardown path.
That leftover is actively harmful: it closes a circular lock-class
dependency with fs_reclaim. The deferred rehash worker takes ht->mutex
and then allocates GFP_KERNEL memory in bucket_table_alloc(),
establishing
&ht->mutex -> fs_reclaim
After commit b32c4a2136 ("xattr: add rhashtable-based simple_xattr
infrastructure") introduced simple_xattr_ht_free(), which calls
rhashtable_free_and_destroy(), the simple_xattrs teardown became
reachable from evict() under the dcache shrinker. The subsequent
per-subsystem adaptations made the reverse edge concrete in three
independent code paths:
* commit 52b364fed6 ("shmem: adapt to rhashtable-based simple_xattrs with lazy allocation")
* commit 5bd97f5c5f ("kernfs: adapt to rhashtable-based simple_xattrs with lazy allocation")
* commit 50704c391f ("pidfs: adapt to rhashtable-based simple_xattrs")
Any of the three closes the cycle
fs_reclaim -> &ht->mutex
which lockdep reports as follows. This particular splat was observed
organically on a workstation kernel built from vfs-7.1-rc1.xattr at
~35h uptime under normal mixed workload, with CONFIG_PROVE_LOCKING=y.
The path happens to go through kernfs:
WARNING: possible circular locking dependency detected
7.0.0-faeab166167f-with-fixes-v1+ #191 Tainted: G U
kswapd0/243 is trying to acquire lock:
ffff8882e475c0f8 (&ht->mutex){+.+.}-{4:4},
at: rhashtable_free_and_destroy+0x36/0x740
but task is already holding lock:
ffffffffa8ad1d00 (fs_reclaim){+.+.}-{0:0},
at: balance_pgdat+0x995/0x1600
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
__lock_acquire+0x506/0xbf0
lock_acquire.part.0+0xc7/0x280
fs_reclaim_acquire+0xd9/0x130
__kvmalloc_node_noprof+0xcd/0xb40
bucket_table_alloc.isra.0+0x5a/0x440
rhashtable_rehash_alloc+0x4e/0xd0
rht_deferred_worker+0x14b/0x440
process_one_work+0x8fd/0x16a0
worker_thread+0x601/0xff0
kthread+0x36b/0x470
ret_from_fork+0x5bf/0x910
ret_from_fork_asm+0x1a/0x30
-> #0 (&ht->mutex){+.+.}-{4:4}:
check_prev_add+0xdb/0xce0
validate_chain+0x554/0x780
__lock_acquire+0x506/0xbf0
lock_acquire.part.0+0xc7/0x280
__mutex_lock+0x1b2/0x2550
rhashtable_free_and_destroy+0x36/0x740
kernfs_put.part.0+0x119/0x570
evict+0x3b6/0x9c0
__dentry_kill+0x181/0x540
shrink_dentry_list+0x135/0x440
prune_dcache_sb+0xdb/0x150
super_cache_scan+0x2ff/0x520
do_shrink_slab+0x35a/0xee0
shrink_slab_memcg+0x457/0x950
shrink_slab+0x43b/0x550
shrink_one+0x31a/0x6f0
shrink_many+0x31e/0xc80
shrink_node+0xeb3/0x14a0
balance_pgdat+0x8ed/0x1600
kswapd+0x2f3/0x530
kthread+0x36b/0x470
ret_from_fork+0x5bf/0x910
ret_from_fork_asm+0x1a/0x30
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&ht->mutex);
lock(fs_reclaim);
lock(&ht->mutex);
Note that lockdep tracks lock classes, not instances: the two
&ht->mutex sites are on different rhashtable objects (the deferred
worker was triggered by some unrelated rhashtable growth), but because
rhashtable_init() uses a single static lockdep key for all rhashtables,
this is a real class-level cycle. Once reported, lockdep disables
itself for the remainder of the boot, masking any subsequent locking
bugs.
Drop the mutex. After cancel_work_sync() the rehash worker is quiesced
and, per this function's contract, no other concurrent access is
possible; the tables are therefore owned exclusively by this function
and can be walked without any lock held.
Switch the table walks from rht_dereference() (which requires
ht->mutex to be held under CONFIG_PROVE_RCU) to rcu_dereference_raw(),
which has no lockdep annotation. rht_ptr_exclusive() already uses
rcu_dereference_protected(p, 1) and needs no change.
This is the only place in lib/rhashtable.c where &ht->mutex is
acquired from a path reachable under fs_reclaim; the deferred worker
is the only other site and it is the forward edge. Removing the
acquisition here therefore eliminates the class cycle for all three
subsystems that use simple_xattrs, not just the one in the splat
above. No locking-semantics change is introduced for correct users;
incorrect users would already be racing with rehash worker completion
regardless of the mutex.
Synthetic reproduction of the splat within a few-minute window was
unsuccessful across several attempts (tmpfs and kernfs zombies via
cgroupfs with open-fd-through-rmdir, with and without swap, up to
~60k reclaim-path executions of simple_xattr_ht_free() in a single
run), consistent with the rare coincidence-of-edges profile of the
bug: the forward edge is already registered in /proc/lockdep on any
idle system via rht_deferred_worker, but the reverse edge requires
evict() to complete kernfs_put()'s final release inside the fs_reclaim
critical section, which in my attempts was ordered against rather than
interleaved with the worker.
Fixes: b32c4a2136 ("xattr: add rhashtable-based simple_xattr infrastructure")
Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The KUNIT_DEBUGFS option is currently enabled based on the value of
KUNIT_ALL_TESTS, but it really doesn't have anything to do with the set of
enabled tests, so just enable it by default anyway. In particular, this
shouldn't be only visible if KUNIT_ALL_TESTS is set, which is quite
confusing.
Link: https://lore.kernel.org/r/20260425034155.53913-1-david@davidgow.net
Fixes: beaed42c42 ("kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS")
Signed-off-by: David Gow <david@davidgow.net>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Pull MM fixes from Andrew Morton:
"20 hotfixes. All are for MM (and for MMish maintainers). 9 are
cc:stable and the remainder are for post-7.0 issues or aren't deemed
suitable for backporting.
There are two DAMON series from SeongJae Park which address races
which could lead to use-after-free errors, and avoid the possibility
of presenting stale parameter values to users"
* tag 'mm-hotfixes-stable-2026-04-30-15-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm: memcontrol: fix rcu unbalance in get_non_dying_memcg_end()
mm/userfaultfd: detect VMA type change after copy retry in mfill_copy_folio_retry()
MAINTAINERS: remove stale kdump project URL
mm/damon/stat: detect and use fresh enabled value
mm/damon/lru_sort: detect and use fresh enabled and kdamond_pid values
mm/damon/reclaim: detect and use fresh enabled and kdamond_pid values
selftests/mm: specify requirement for PROC_MEM_ALWAYS_FORCE=y
mm/damon/sysfs-schemes: protect path kfree() with damon_sysfs_lock
mm/damon/sysfs-schemes: protect memcg_path kfree() with damon_sysfs_lock
MAINTAINERS: update Li Wang's email address
MAINTAINERS, mailmap: update email address for Qi Zheng
MAINTAINERS: update Liam's email address
mm/hugetlb_cma: round up per_node before logging it
MAINTAINERS: fix regex pattern in CORE MM category
mm/vma: do not try to unmap a VMA if mmap_prepare() invoked from mmap()
mm: start background writeback based on per-wb threshold for strictlimit BDIs
kho: fix error handling in kho_add_subtree()
liveupdate: fix return value on session allocation failure
mailmap: update entry for Dan Carpenter
vmalloc: fix buffer overflow in vrealloc_node_align()
