kernel/linux.git/drivers/char/random.c, branch v6.18.21

Remove WARN_ALL_UNSEEDED_RANDOM kernel config option

2026-03-04T12:20:46+00:00

[ Upstream commit 7dff99b354601dd01829e1511711846e04340a69 ] 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: cc1e127bfa95 ("random: remove ratelimiting for in-kernel unseeded randomness") Acked-by: Jason Donenfeld Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

random: use offstack cpumask when necessary

2025-12-18T13:02:44+00:00

[ Upstream commit 5d49f1a5bd358d24e5f88b23b46da833de1dbec8 ] 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: 1c21fe00eda7 ("random: spread out jitter callback to different CPUs") Signed-off-by: Arnd Bergmann Signed-off-by: Jason A. Donenfeld Signed-off-by: Sasha Levin

Merge tag 'ratelimit.2025.05.25a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

2025-05-27T17:48:36+00:00

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

Merge tag 'timers-cleanups-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-05-27T15:31:21+00:00

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()

crypto: lib/chacha - add strongly-typed state zeroization

2025-05-12T05:32:53+00:00

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 Signed-off-by: Herbert Xu

crypto: lib/chacha - strongly type the ChaCha state

2025-05-12T05:32:53+00:00

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 Acked-by: Kent Overstreet Signed-off-by: Herbert Xu

random: Avoid open-coded use of ratelimit_state structure's ->missed field

2025-05-08T23:13:26+00:00

The _credit_init_bits() function directly accesses the ratelimit_state structure's ->missed field, which works, but which also makes it more difficult to change this field. Therefore, make use of the ratelimit_state_get_miss() and ratelimit_state_inc_miss() functions instead of directly accessing the ->missed field. Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/ Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/ Signed-off-by: Paul E. McKenney Reviewed-by: Petr Mladek Cc: "Theodore Ts'o" "Jason A. Donenfeld"

treewide, timers: Rename destroy_timer_on_stack() as timer_destroy_on_stack()

2025-05-08T17:49:33+00:00

Move this API to the canonical timer_*() namespace. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250507175338.672442-10-mingo@kernel.org

treewide, timers: Rename try_to_del_timer_sync() as timer_delete_sync_try()

2025-05-08T17:49:33+00:00

Move this API to the canonical timer_*() namespace. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250507175338.672442-9-mingo@kernel.org

treewide: Switch/rename to timer_delete[_sync]()

2025-04-05T08:30:12+00:00

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 Signed-off-by: Ingo Molnar