* [PATCH] random: do not take pool spinlock at boot
@ 2022-02-12 0:28 Jason A. Donenfeld
2022-02-12 5:04 ` kernel test robot
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: Jason A. Donenfeld @ 2022-02-12 0:28 UTC (permalink / raw)
To: linux, linux-kernel; +Cc: Jason A. Donenfeld
Since rand_initialize() is run while interrupts are still off and
nothing else is running, we don't need to repeatedly take and release
the pool spinlock, especially in the RDSEED loop.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
Dominik - I'm still a bit unclear about early boot semantics that you
seem to know well. Is this patch correct?
drivers/char/random.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index d4b692c9de68..8088348190e6 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -966,10 +966,10 @@ int __init rand_initialize(void)
rv = random_get_entropy();
arch_init = false;
}
- mix_pool_bytes(&rv, sizeof(rv));
+ _mix_pool_bytes(&rv, sizeof(rv));
}
- mix_pool_bytes(&now, sizeof(now));
- mix_pool_bytes(utsname(), sizeof(*(utsname())));
+ _mix_pool_bytes(&now, sizeof(now));
+ _mix_pool_bytes(utsname(), sizeof(*(utsname())));
extract_entropy(base_crng.key, sizeof(base_crng.key));
++base_crng.generation;
--
2.35.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] random: do not take pool spinlock at boot
2022-02-12 0:28 [PATCH] random: do not take pool spinlock at boot Jason A. Donenfeld
@ 2022-02-12 5:04 ` kernel test robot
2022-02-12 5:35 ` kernel test robot
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: kernel test robot @ 2022-02-12 5:04 UTC (permalink / raw)
To: kbuild-all
[-- Attachment #1: Type: text/plain, Size: 3196 bytes --]
Hi "Jason,
I love your patch! Perhaps something to improve:
[auto build test WARNING on next-20220211]
[cannot apply to char-misc/char-misc-testing linux/master linus/master v5.17-rc3 v5.17-rc2 v5.17-rc1 v5.17-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
base: 6d9bd4ad4ca08b1114e814c2c42383b8b13be631
config: um-x86_64_defconfig (https://download.01.org/0day-ci/archive/20220212/202202121223.7CKs3pQ3-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/cac377f6ab22a8bfe966643ebe19812e8187de3b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
git checkout cac377f6ab22a8bfe966643ebe19812e8187de3b
# save the config file to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash drivers/char/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
drivers/char/random.c: In function 'rand_initialize':
drivers/char/random.c:162:3: error: implicit declaration of function '_mix_pool_bytes'; did you mean 'mix_pool_bytes'? [-Werror=implicit-function-declaration]
162 | _mix_pool_bytes(&rv, sizeof(rv));
| ^~~~~~~~~~~~~~~
| mix_pool_bytes
drivers/char/random.c: At top level:
>> drivers/char/random.c:822:13: warning: conflicting types for '_mix_pool_bytes'
822 | static void _mix_pool_bytes(const void *in, size_t nbytes)
| ^~~~~~~~~~~~~~~
drivers/char/random.c:822:13: error: static declaration of '_mix_pool_bytes' follows non-static declaration
drivers/char/random.c:162:3: note: previous implicit declaration of '_mix_pool_bytes' was here
162 | _mix_pool_bytes(&rv, sizeof(rv));
| ^~~~~~~~~~~~~~~
drivers/char/random.c:1109:6: warning: no previous prototype for 'add_hwgenerator_randomness' [-Wmissing-prototypes]
1109 | void add_hwgenerator_randomness(const void *buffer, size_t count,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +/_mix_pool_bytes +822 drivers/char/random.c
b980955236922ae Theodore Ts'o 2013-03-04 821
b67959013391e48 Jason A. Donenfeld 2022-02-10 @822 static void _mix_pool_bytes(const void *in, size_t nbytes)
b67959013391e48 Jason A. Donenfeld 2022-02-10 823 {
b67959013391e48 Jason A. Donenfeld 2022-02-10 824 blake2s_update(&input_pool.hash, in, nbytes);
^1da177e4c3f415 Linus Torvalds 2005-04-16 825 }
^1da177e4c3f415 Linus Torvalds 2005-04-16 826
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] random: do not take pool spinlock at boot
2022-02-12 0:28 [PATCH] random: do not take pool spinlock at boot Jason A. Donenfeld
2022-02-12 5:04 ` kernel test robot
@ 2022-02-12 5:35 ` kernel test robot
2022-02-12 10:01 ` Jason A. Donenfeld
2022-02-13 6:55 ` Dominik Brodowski
2022-02-21 5:34 ` Eric Biggers
3 siblings, 1 reply; 7+ messages in thread
From: kernel test robot @ 2022-02-12 5:35 UTC (permalink / raw)
To: kbuild-all
[-- Attachment #1: Type: text/plain, Size: 4290 bytes --]
Hi "Jason,
I love your patch! Yet something to improve:
[auto build test ERROR on next-20220211]
[cannot apply to char-misc/char-misc-testing linux/master linus/master v5.17-rc3 v5.17-rc2 v5.17-rc1 v5.17-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
base: 6d9bd4ad4ca08b1114e814c2c42383b8b13be631
config: um-x86_64_defconfig (https://download.01.org/0day-ci/archive/20220212/202202121318.QSBkUcwP-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/cac377f6ab22a8bfe966643ebe19812e8187de3b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
git checkout cac377f6ab22a8bfe966643ebe19812e8187de3b
# save the config file to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
drivers/char/random.c: In function 'rand_initialize':
>> drivers/char/random.c:162:3: error: implicit declaration of function '_mix_pool_bytes'; did you mean 'mix_pool_bytes'? [-Werror=implicit-function-declaration]
162 | _mix_pool_bytes(&rv, sizeof(rv));
| ^~~~~~~~~~~~~~~
| mix_pool_bytes
drivers/char/random.c: At top level:
drivers/char/random.c:822:13: warning: conflicting types for '_mix_pool_bytes'
822 | static void _mix_pool_bytes(const void *in, size_t nbytes)
| ^~~~~~~~~~~~~~~
>> drivers/char/random.c:822:13: error: static declaration of '_mix_pool_bytes' follows non-static declaration
drivers/char/random.c:162:3: note: previous implicit declaration of '_mix_pool_bytes' was here
162 | _mix_pool_bytes(&rv, sizeof(rv));
| ^~~~~~~~~~~~~~~
drivers/char/random.c:1109:6: warning: no previous prototype for 'add_hwgenerator_randomness' [-Wmissing-prototypes]
1109 | void add_hwgenerator_randomness(const void *buffer, size_t count,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +162 drivers/char/random.c
138
139 /*
140 * Note that setup_arch() may call add_device_randomness()
141 * long before we get here. This allows seeding of the pools
142 * with some platform dependent data very early in the boot
143 * process. But it limits our options here. We must use
144 * statically allocated structures that already have all
145 * initializations complete at compile time. We should also
146 * take care not to overwrite the precious per platform data
147 * we were given.
148 */
149 int __init rand_initialize(void)
150 {
151 size_t i;
152 ktime_t now = ktime_get_real();
153 bool arch_init = true;
154 unsigned long rv;
155
156 for (i = BLAKE2S_BLOCK_SIZE; i > 0; i -= sizeof(rv)) {
157 if (!arch_get_random_seed_long_early(&rv) &&
158 !arch_get_random_long_early(&rv)) {
159 rv = random_get_entropy();
160 arch_init = false;
161 }
> 162 _mix_pool_bytes(&rv, sizeof(rv));
163 }
164 _mix_pool_bytes(&now, sizeof(now));
165 _mix_pool_bytes(utsname(), sizeof(*(utsname())));
166
167 extract_entropy(base_crng.key, sizeof(base_crng.key));
168 ++base_crng.generation;
169
170 if (arch_init && trust_cpu && crng_init < 2) {
171 crng_init = 2;
172 pr_notice("crng init done (trusting CPU's manufacturer)\n");
173 }
174
175 if (ratelimit_disable) {
176 urandom_warning.interval = 0;
177 unseeded_warning.interval = 0;
178 }
179 return 0;
180 }
181
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] random: do not take pool spinlock at boot
2022-02-12 5:35 ` kernel test robot
@ 2022-02-12 10:01 ` Jason A. Donenfeld
2022-02-14 6:40 ` Chen, Rong A
0 siblings, 1 reply; 7+ messages in thread
From: Jason A. Donenfeld @ 2022-02-12 10:01 UTC (permalink / raw)
To: kbuild-all
[-- Attachment #1: Type: text/plain, Size: 5056 bytes --]
Hey folks,
Just FYI, this applied to the wrong tree. It should have applied to
https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git
Regards,
Jason
On Sat, Feb 12, 2022, 06:35 kernel test robot <lkp@intel.com> wrote:
> Hi "Jason,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on next-20220211]
> [cannot apply to char-misc/char-misc-testing linux/master linus/master
> v5.17-rc3 v5.17-rc2 v5.17-rc1 v5.17-rc3]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url:
> https://github.com/0day-ci/linux/commits/Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
> base: 6d9bd4ad4ca08b1114e814c2c42383b8b13be631
> config: um-x86_64_defconfig (
> https://download.01.org/0day-ci/archive/20220212/202202121318.QSBkUcwP-lkp(a)intel.com/config
> )
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
> #
> https://github.com/0day-ci/linux/commit/cac377f6ab22a8bfe966643ebe19812e8187de3b
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review
> Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
> git checkout cac377f6ab22a8bfe966643ebe19812e8187de3b
> # save the config file to linux build tree
> mkdir build_dir
> make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
> drivers/char/random.c: In function 'rand_initialize':
> >> drivers/char/random.c:162:3: error: implicit declaration of function
> '_mix_pool_bytes'; did you mean 'mix_pool_bytes'?
> [-Werror=implicit-function-declaration]
> 162 | _mix_pool_bytes(&rv, sizeof(rv));
> | ^~~~~~~~~~~~~~~
> | mix_pool_bytes
> drivers/char/random.c: At top level:
> drivers/char/random.c:822:13: warning: conflicting types for
> '_mix_pool_bytes'
> 822 | static void _mix_pool_bytes(const void *in, size_t nbytes)
> | ^~~~~~~~~~~~~~~
> >> drivers/char/random.c:822:13: error: static declaration of
> '_mix_pool_bytes' follows non-static declaration
> drivers/char/random.c:162:3: note: previous implicit declaration of
> '_mix_pool_bytes' was here
> 162 | _mix_pool_bytes(&rv, sizeof(rv));
> | ^~~~~~~~~~~~~~~
> drivers/char/random.c:1109:6: warning: no previous prototype for
> 'add_hwgenerator_randomness' [-Wmissing-prototypes]
> 1109 | void add_hwgenerator_randomness(const void *buffer, size_t
> count,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
>
>
> vim +162 drivers/char/random.c
>
> 138
> 139 /*
> 140 * Note that setup_arch() may call add_device_randomness()
> 141 * long before we get here. This allows seeding of the pools
> 142 * with some platform dependent data very early in the boot
> 143 * process. But it limits our options here. We must use
> 144 * statically allocated structures that already have all
> 145 * initializations complete at compile time. We should also
> 146 * take care not to overwrite the precious per platform data
> 147 * we were given.
> 148 */
> 149 int __init rand_initialize(void)
> 150 {
> 151 size_t i;
> 152 ktime_t now = ktime_get_real();
> 153 bool arch_init = true;
> 154 unsigned long rv;
> 155
> 156 for (i = BLAKE2S_BLOCK_SIZE; i > 0; i -= sizeof(rv)) {
> 157 if (!arch_get_random_seed_long_early(&rv) &&
> 158 !arch_get_random_long_early(&rv)) {
> 159 rv = random_get_entropy();
> 160 arch_init = false;
> 161 }
> > 162 _mix_pool_bytes(&rv, sizeof(rv));
> 163 }
> 164 _mix_pool_bytes(&now, sizeof(now));
> 165 _mix_pool_bytes(utsname(), sizeof(*(utsname())));
> 166
> 167 extract_entropy(base_crng.key, sizeof(base_crng.key));
> 168 ++base_crng.generation;
> 169
> 170 if (arch_init && trust_cpu && crng_init < 2) {
> 171 crng_init = 2;
> 172 pr_notice("crng init done (trusting CPU's
> manufacturer)\n");
> 173 }
> 174
> 175 if (ratelimit_disable) {
> 176 urandom_warning.interval = 0;
> 177 unseeded_warning.interval = 0;
> 178 }
> 179 return 0;
> 180 }
> 181
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
>
[-- Attachment #2: attachment.htm --]
[-- Type: text/html, Size: 7081 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] random: do not take pool spinlock at boot
2022-02-12 0:28 [PATCH] random: do not take pool spinlock at boot Jason A. Donenfeld
2022-02-12 5:04 ` kernel test robot
2022-02-12 5:35 ` kernel test robot
@ 2022-02-13 6:55 ` Dominik Brodowski
2022-02-21 5:34 ` Eric Biggers
3 siblings, 0 replies; 7+ messages in thread
From: Dominik Brodowski @ 2022-02-13 6:55 UTC (permalink / raw)
To: Jason A. Donenfeld; +Cc: linux-kernel
Am Sat, Feb 12, 2022 at 01:28:59AM +0100 schrieb Jason A. Donenfeld:
> Since rand_initialize() is run while interrupts are still off and
> nothing else is running, we don't need to repeatedly take and release
> the pool spinlock, especially in the RDSEED loop.
>
> Cc: Dominik Brodowski <linux@dominikbrodowski.net>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> Dominik - I'm still a bit unclear about early boot semantics that you
> seem to know well. Is this patch correct?
It seems to be.
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Thanks,
Dominik
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] random: do not take pool spinlock at boot
2022-02-12 10:01 ` Jason A. Donenfeld
@ 2022-02-14 6:40 ` Chen, Rong A
0 siblings, 0 replies; 7+ messages in thread
From: Chen, Rong A @ 2022-02-14 6:40 UTC (permalink / raw)
To: kbuild-all
[-- Attachment #1: Type: text/plain, Size: 6856 bytes --]
Hi Jason,
Thanks for the explanation, we'll take a look.
Best Regards,
Rong Chen
On 2/12/2022 6:01 PM, Jason A. Donenfeld wrote:
> Hey folks,
>
> Just FYI, this applied to the wrong tree. It should have applied to
> https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git
> <https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git>
>
> Regards,
> Jason
>
>
> On Sat, Feb 12, 2022, 06:35 kernel test robot <lkp@intel.com
> <mailto:lkp@intel.com>> wrote:
>
> Hi "Jason,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on next-20220211]
> [cannot apply to char-misc/char-misc-testing linux/master
> linus/master v5.17-rc3 v5.17-rc2 v5.17-rc1 v5.17-rc3]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch
> <https://git-scm.com/docs/git-format-patch>]
>
> url:
> https://github.com/0day-ci/linux/commits/Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
> <https://github.com/0day-ci/linux/commits/Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131>
> base: 6d9bd4ad4ca08b1114e814c2c42383b8b13be631
> config: um-x86_64_defconfig
> (https://download.01.org/0day-ci/archive/20220212/202202121318.QSBkUcwP-lkp(a)intel.com/config
> <https://download.01.org/0day-ci/archive/20220212/202202121318.QSBkUcwP-lkp@intel.com/config>)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
> #
> https://github.com/0day-ci/linux/commit/cac377f6ab22a8bfe966643ebe19812e8187de3b
> <https://github.com/0day-ci/linux/commit/cac377f6ab22a8bfe966643ebe19812e8187de3b>
> git remote add linux-review
> https://github.com/0day-ci/linux <https://github.com/0day-ci/linux>
> git fetch --no-tags linux-review
> Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131
> git checkout cac377f6ab22a8bfe966643ebe19812e8187de3b
> # save the config file to linux build tree
> mkdir build_dir
> make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp(a)intel.com <mailto:lkp@intel.com>>
>
> All errors (new ones prefixed by >>):
>
> drivers/char/random.c: In function 'rand_initialize':
> >> drivers/char/random.c:162:3: error: implicit declaration of
> function '_mix_pool_bytes'; did you mean 'mix_pool_bytes'?
> [-Werror=implicit-function-declaration]
> 162 | _mix_pool_bytes(&rv, sizeof(rv));
> | ^~~~~~~~~~~~~~~
> | mix_pool_bytes
> drivers/char/random.c: At top level:
> drivers/char/random.c:822:13: warning: conflicting types for
> '_mix_pool_bytes'
> 822 | static void _mix_pool_bytes(const void *in, size_t nbytes)
> | ^~~~~~~~~~~~~~~
> >> drivers/char/random.c:822:13: error: static declaration of
> '_mix_pool_bytes' follows non-static declaration
> drivers/char/random.c:162:3: note: previous implicit declaration
> of '_mix_pool_bytes' was here
> 162 | _mix_pool_bytes(&rv, sizeof(rv));
> | ^~~~~~~~~~~~~~~
> drivers/char/random.c:1109:6: warning: no previous prototype for
> 'add_hwgenerator_randomness' [-Wmissing-prototypes]
> 1109 | void add_hwgenerator_randomness(const void *buffer,
> size_t count,
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
>
>
> vim +162 drivers/char/random.c
>
> 138
> 139 /*
> 140 * Note that setup_arch() may call add_device_randomness()
> 141 * long before we get here. This allows seeding of the pools
> 142 * with some platform dependent data very early in the boot
> 143 * process. But it limits our options here. We must use
> 144 * statically allocated structures that already have all
> 145 * initializations complete at compile time. We should also
> 146 * take care not to overwrite the precious per platform data
> 147 * we were given.
> 148 */
> 149 int __init rand_initialize(void)
> 150 {
> 151 size_t i;
> 152 ktime_t now = ktime_get_real();
> 153 bool arch_init = true;
> 154 unsigned long rv;
> 155
> 156 for (i = BLAKE2S_BLOCK_SIZE; i > 0; i -= sizeof(rv)) {
> 157 if (!arch_get_random_seed_long_early(&rv) &&
> 158 !arch_get_random_long_early(&rv)) {
> 159 rv = random_get_entropy();
> 160 arch_init = false;
> 161 }
> > 162 _mix_pool_bytes(&rv, sizeof(rv));
> 163 }
> 164 _mix_pool_bytes(&now, sizeof(now));
> 165 _mix_pool_bytes(utsname(), sizeof(*(utsname())));
> 166
> 167 extract_entropy(base_crng.key, sizeof(base_crng.key));
> 168 ++base_crng.generation;
> 169
> 170 if (arch_init && trust_cpu && crng_init < 2) {
> 171 crng_init = 2;
> 172 pr_notice("crng init done (trusting CPU's
> manufacturer)\n");
> 173 }
> 174
> 175 if (ratelimit_disable) {
> 176 urandom_warning.interval = 0;
> 177 unseeded_warning.interval = 0;
> 178 }
> 179 return 0;
> 180 }
> 181
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
> <https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org>
>
>
> _______________________________________________
> kbuild-all mailing list -- kbuild-all(a)lists.01.org
> To unsubscribe send an email to kbuild-all-leave(a)lists.01.org
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] random: do not take pool spinlock at boot
2022-02-12 0:28 [PATCH] random: do not take pool spinlock at boot Jason A. Donenfeld
` (2 preceding siblings ...)
2022-02-13 6:55 ` Dominik Brodowski
@ 2022-02-21 5:34 ` Eric Biggers
3 siblings, 0 replies; 7+ messages in thread
From: Eric Biggers @ 2022-02-21 5:34 UTC (permalink / raw)
To: Jason A. Donenfeld; +Cc: linux, linux-kernel
On Sat, Feb 12, 2022 at 01:28:59AM +0100, Jason A. Donenfeld wrote:
> Since rand_initialize() is run while interrupts are still off and
> nothing else is running, we don't need to repeatedly take and release
> the pool spinlock, especially in the RDSEED loop.
>
> Cc: Dominik Brodowski <linux@dominikbrodowski.net>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> Dominik - I'm still a bit unclear about early boot semantics that you
> seem to know well. Is this patch correct?
>
> drivers/char/random.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index d4b692c9de68..8088348190e6 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -966,10 +966,10 @@ int __init rand_initialize(void)
> rv = random_get_entropy();
> arch_init = false;
> }
> - mix_pool_bytes(&rv, sizeof(rv));
> + _mix_pool_bytes(&rv, sizeof(rv));
> }
> - mix_pool_bytes(&now, sizeof(now));
> - mix_pool_bytes(utsname(), sizeof(*(utsname())));
> + _mix_pool_bytes(&now, sizeof(now));
> + _mix_pool_bytes(utsname(), sizeof(*(utsname())));
>
> extract_entropy(base_crng.key, sizeof(base_crng.key));
> ++base_crng.generation;
> --
> 2.35.0
Reviewed-by: Eric Biggers <ebiggers@google.com>
- Eric
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-02-21 5:35 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-12 0:28 [PATCH] random: do not take pool spinlock at boot Jason A. Donenfeld
2022-02-12 5:04 ` kernel test robot
2022-02-12 5:35 ` kernel test robot
2022-02-12 10:01 ` Jason A. Donenfeld
2022-02-14 6:40 ` Chen, Rong A
2022-02-13 6:55 ` Dominik Brodowski
2022-02-21 5:34 ` Eric Biggers
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