This config option goes way back - it used to be an internal debug
option to random.c (at that point called DEBUG_RANDOM_BOOT), then was
renamed and exposed as a config option as CONFIG_WARN_UNSEEDED_RANDOM,
and then further renamed to the current CONFIG_WARN_ALL_UNSEEDED_RANDOM.
It was all done with the best of intentions: the more limited
rate-limited reports were reporting some cases, but if you wanted to see
all the gory details, you'd enable this "ALL" option.
However, it turns out - perhaps not surprisingly - that when people
don't care about and fix the first rate-limited cases, they most
certainly don't care about any others either, and so warning about all
of them isn't actually helping anything.
And the non-ratelimited reporting causes problems, where well-meaning
people enable debug options, but the excessive flood of messages that
nobody cares about will hide actual real information when things go
wrong.
I just got a kernel bug report (which had nothing to do with randomness)
where two thirds of the the truncated dmesg was just variations of
random: get_random_u32 called from __get_random_u32_below+0x10/0x70 with crng_init=0
and in the process early boot messages had been lost (in addition to
making the messages that _hadn't_ been lost harder to read).
The proper way to find these things for the hypothetical developer that
cares - if such a person exists - is almost certainly with boot time
tracing. That gives you the option to get call graphs etc too, which is
likely a requirement for fixing any problems anyway.
See Documentation/trace/boottime-trace.rst for that option.
And if we for some reason do want to re-introduce actual printing of
these things, it will need to have some uniqueness filtering rather than
this "just print it all" model.
Fixes: cc1e127bfa ("random: remove ratelimiting for in-kernel unseeded randomness")
Acked-by: Jason Donenfeld <Jason@zx2c4.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Pull random number generator updates from Jason Donenfeld:
- Dynamically allocate cpumasks off of the stack if the kernel is
configured for a lot of CPUs, to handle a -Wframe-larger-than case
- The removal of next_pseudo_random32() after the last user was
switched over to the prandom interface
- The removal of get_random_u{8,16,32,64}_wait() functions, as there
were no users of those at all
- Some house keeping changes - a few grammar cleanups in the
comments, system_unbound_wq was renamed to system_dfl_wq, and
static_key_initialized no longer needs to be checked
* tag 'random-6.19-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
random: complete sentence of comment
random: drop check for static_key_initialized
random: remove unused get_random_var_wait functions
random: replace use of system_unbound_wq with system_dfl_wq
random: use offstack cpumask when necessary
prandom: remove next_pseudo_random32
media: vivid: use prandom
random: add missing words in function comments
Commit e871abcda3 ("random: handle creditable entropy from atomic
process context") added the use of workqueues, which meant testing
whether the workqueue is valid, but it did not remove the existing check
of whether static keys have been initialized. This static key check is
unnecessary because workqueues are initialized long after it. And
semantically it doesn't make much sense either, because it's not really
directly calling a static key function in the condition.
Remove the now unnecessary check.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
[Jason: rewrite commit message with different explanation, rebase on
random.git, and update code comment.]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
system_unbound_wq has been renamed to system_dfl_wq in 128ea9f6cc
("workqueue: Add system_percpu_wq and system_dfl_wq"), so update
random.c's usage of it system_unbound_wq to reflect the new change. The
old system_unbound_wq is slated for removal in the next few cycles.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The entropy generation function keeps a local cpu mask on the stack,
which can trigger warnings in configurations with a large number of
CPUs:
drivers/char/random.c:1292:20: error: stack frame size (1288)
exceeds limit (1280) in 'try_to_generate_entropy' [-Werror,-Wframe-larger-than]
Use the cpumask interface to dynamically allocate it in those
configurations.
Fixes: 1c21fe00ed ("random: spread out jitter callback to different CPUs")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
For consistency with the SHA-1, SHA-2, SHA-3 (in development), and MD5
library APIs, rename blake2s_state to blake2s_ctx.
As a refresher, the ctx name:
- Is a bit shorter.
- Avoids confusion with the compression function state, which is also
often called the state (but is just part of the full context).
- Is consistent with OpenSSL.
Not a big deal, of course. But consistency is nice. With a BLAKE2b
library API about to be added, this is a convenient time to update this.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251018043106.375964-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reorder the parameters of blake2s() from (out, in, key, outlen, inlen,
keylen) to (key, keylen, in, inlen, out, outlen).
This aligns BLAKE2s with the common conventions of pairing buffers and
their lengths, and having outputs follow inputs. This is widely used
elsewhere in lib/crypto/ and crypto/, and even elsewhere in the BLAKE2s
code itself such as blake2s_init_key() and blake2s_final(). So
blake2s() was a bit of an exception.
Notably, this results in the same order as hmac_*_usingrawkey().
Note that since the type signature changed, it's not possible for a
blake2s() call site to be silently missed.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251018043106.375964-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Pull rate-limit updates from Paul McKenney:
"lib/ratelimit: Reduce false-positive and silent misses:
- Reduce open-coded use of ratelimit_state structure fields.
- Convert the ->missed field to atomic_t.
- Count misses that are due to lock contention.
- Eliminate jiffies=0 special case.
- Reduce ___ratelimit() false-positive rate limiting (Petr Mladek).
- Allow zero ->burst to hard-disable rate limiting.
- Optimize away atomic operations when a miss is guaranteed.
- Warn if ->interval or ->burst are negative (Petr Mladek).
- Simplify the resulting code.
A smoke test and stress test have been created, but they are not yet
ready for mainline. With luck, we will offer them for the v6.17 merge
window"
* tag 'ratelimit.2025.05.25a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
ratelimit: Drop redundant accesses to burst
ratelimit: Use nolock_ret restructuring to collapse common case code
ratelimit: Use nolock_ret label to collapse lock-failure code
ratelimit: Use nolock_ret label to save a couple of lines of code
ratelimit: Simplify common-case exit path
ratelimit: Warn if ->interval or ->burst are negative
ratelimit: Avoid atomic decrement under lock if already rate-limited
ratelimit: Avoid atomic decrement if already rate-limited
ratelimit: Don't flush misses counter if RATELIMIT_MSG_ON_RELEASE
ratelimit: Force re-initialization when rate-limiting re-enabled
ratelimit: Allow zero ->burst to disable ratelimiting
ratelimit: Reduce ___ratelimit() false-positive rate limiting
ratelimit: Avoid jiffies=0 special case
ratelimit: Count misses due to lock contention
ratelimit: Convert the ->missed field to atomic_t
drm/amd/pm: Avoid open-coded use of ratelimit_state structure's internals
drm/i915: Avoid open-coded use of ratelimit_state structure's ->missed field
random: Avoid open-coded use of ratelimit_state structure's ->missed field
ratelimit: Create functions to handle ratelimit_state internals
Pull timer cleanups from Thomas Gleixner:
"Another set of timer API cleanups:
- Convert init_timer*(), try_to_del_timer_sync() and
destroy_timer_on_stack() over to the canonical timer_*()
namespace convention.
There is another large conversion pending, which has not been included
because it would have caused a gazillion of merge conflicts in next.
The conversion scripts will be run towards the end of the merge window
and a pull request sent once all conflict dependencies have been
merged"
* tag 'timers-cleanups-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
treewide, timers: Rename destroy_timer_on_stack() as timer_destroy_on_stack()
treewide, timers: Rename try_to_del_timer_sync() as timer_delete_sync_try()
timers: Rename init_timers() as timers_init()
timers: Rename NEXT_TIMER_MAX_DELTA as TIMER_NEXT_MAX_DELTA
timers: Rename __init_timer_on_stack() as __timer_init_on_stack()
timers: Rename __init_timer() as __timer_init()
timers: Rename init_timer_on_stack_key() as timer_init_key_on_stack()
timers: Rename init_timer_key() as timer_init_key()
Now that the ChaCha state matrix is strongly-typed, add a helper
function chacha_zeroize_state() which zeroizes it. Then convert all
applicable callers to use it instead of direct memzero_explicit. No
functional changes.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The ChaCha state matrix is 16 32-bit words. Currently it is represented
in the code as a raw u32 array, or even just a pointer to u32. This
weak typing is error-prone. Instead, introduce struct chacha_state:
struct chacha_state {
u32 x[16];
};
Convert all ChaCha and HChaCha functions to use struct chacha_state.
No functional changes.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Extend the generic vDSO data storage with a page for the random state data.
The random state data is stored in a dedicated page, as the existing
storage page is only meant for time-related, time-namespace-aware data.
This simplifies to access logic to not need to handle time namespaces
anymore and also frees up more space in the time-related page.
In case further generic vDSO data store is required it can be added to
the random state page.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-6-13a4669dfc8c@linutronix.de
Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.
Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25c ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.
Created this by running an spatch followed by a sed command:
Spatch:
virtual patch
@
depends on !(file in "net")
disable optional_qualifier
@
identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@
+ const
struct ctl_table table_name [] = { ... };
sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c
Reviewed-by: Song Liu <song@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> # for kernel/trace/
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> # SCSI
Reviewed-by: Darrick J. Wong <djwong@kernel.org> # xfs
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Acked-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
_vdso_data is specific to x86 and __arch_get_k_vdso_data() is provided
so that all architectures can provide the requested pointer.
Do the same with _vdso_rng_data, provide __arch_get_k_vdso_rng_data()
and don't use x86 _vdso_rng_data directly.
Until now vdso/vsyscall.h was only included by time/vsyscall.c but now
it will also be included in char/random.c, leading to a duplicate
declaration of _vdso_data and _vdso_rng_data.
To fix this issue, move the declaration in a C file. vma.c looks like
the most appropriate candidate. We don't need to replace the definitions
in vsyscall.h by declarations as declarations are already in asm/vvar.h.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Performing SMP atomic operations on u64 fails on powerpc32:
CC drivers/char/random.o
In file included from <command-line>:
drivers/char/random.c: In function 'crng_reseed':
././include/linux/compiler_types.h:510:45: error: call to '__compiletime_assert_391' declared with attribute error: Need native word sized stores/loads for atomicity.
510 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
././include/linux/compiler_types.h:491:25: note: in definition of macro '__compiletime_assert'
491 | prefix ## suffix(); \
| ^~~~~~
././include/linux/compiler_types.h:510:9: note: in expansion of macro '_compiletime_assert'
510 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
././include/linux/compiler_types.h:513:9: note: in expansion of macro 'compiletime_assert'
513 | compiletime_assert(__native_word(t), \
| ^~~~~~~~~~~~~~~~~~
./arch/powerpc/include/asm/barrier.h:74:9: note: in expansion of macro 'compiletime_assert_atomic_type'
74 | compiletime_assert_atomic_type(*p); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/asm-generic/barrier.h:172:55: note: in expansion of macro '__smp_store_release'
172 | #define smp_store_release(p, v) do { kcsan_release(); __smp_store_release(p, v); } while (0)
| ^~~~~~~~~~~~~~~~~~~
drivers/char/random.c:286:9: note: in expansion of macro 'smp_store_release'
286 | smp_store_release(&__arch_get_k_vdso_rng_data()->generation, next_gen + 1);
| ^~~~~~~~~~~~~~~~~
The kernel-side generation counter in the random driver is handled as an
unsigned long, not as a u64, in base_crng and struct crng.
But on the vDSO side, it needs to be an u64, not just an unsigned long,
in order to support a 32-bit vDSO atop a 64-bit kernel.
On kernel side, however, it is an unsigned long, hence a 32-bit value on
32-bit architectures, so just cast it to unsigned long for the
smp_store_release(). A side effect is that on big endian architectures
the store will be performed in the upper 32 bits. It is not an issue on
its own because the vDSO site doesn't mind the value, as it only checks
differences. Just make sure that the vDSO side checks the full 64 bits.
For that, the local current_generation has to be u64 as well.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
