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320f2dce19
commit36cb649442upstream. There are two deadlock scenarios that need addressing, which cause problems when the computer goes to sleep, the interface is set down, and hwrng_unregister() is called. When the deadlock is hit, sleep is delayed for tens of seconds, causing it to fail. These scenarios are: 1) The hwrng kthread can't be stopped while it's sleeping, because it uses msleep_interruptible() which does not react to kthread_stop. 2) A normal user thread can't be interrupted by hwrng_unregister() while it's sleeping, because hwrng_unregister() is called from elsewhere. We solve both issues by add a completion object called dying that fulfils waiters once we have started the process in hwrng_unregister. At the same time, we should cleanup a common and useless dmesg splat in the same area. Cc: <stable@vger.kernel.org> Reported-by: Gregory Erwin <gregerwin256@gmail.com> Fixes:fcd09c90c3("ath9k: use hw_random API instead of directly dumping into random.c") Link: https://lore.kernel.org/all/CAO+Okf6ZJC5-nTE_EJUGQtd8JiCkiEHytGgDsFGTEjs0c00giw@mail.gmail.com/ Link: https://lore.kernel.org/lkml/CAO+Okf5k+C+SE6pMVfPf-d8MfVPVq4PO7EY8Hys_DVXtent3HA@mail.gmail.com/ Link: https://bugs.archlinux.org/task/75138 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Acked-by: Kalle Valo <kvalo@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
67 lines
2.2 KiB
C
67 lines
2.2 KiB
C
/*
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Hardware Random Number Generator
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Please read Documentation/admin-guide/hw_random.rst for details on use.
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----------------------------------------------------------
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This software may be used and distributed according to the terms
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of the GNU General Public License, incorporated herein by reference.
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*/
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#ifndef LINUX_HWRANDOM_H_
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#define LINUX_HWRANDOM_H_
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#include <linux/completion.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/kref.h>
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/**
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* struct hwrng - Hardware Random Number Generator driver
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* @name: Unique RNG name.
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* @init: Initialization callback (can be NULL).
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* @cleanup: Cleanup callback (can be NULL).
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* @data_present: Callback to determine if data is available
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* on the RNG. If NULL, it is assumed that
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* there is always data available. *OBSOLETE*
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* @data_read: Read data from the RNG device.
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* Returns the number of lower random bytes in "data".
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* Must not be NULL. *OBSOLETE*
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* @read: New API. drivers can fill up to max bytes of data
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* into the buffer. The buffer is aligned for any type
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* and max is a multiple of 4 and >= 32 bytes.
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* @priv: Private data, for use by the RNG driver.
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* @quality: Estimation of true entropy in RNG's bitstream
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* (in bits of entropy per 1024 bits of input;
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* valid values: 1 to 1024, or 0 for unknown).
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*/
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struct hwrng {
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const char *name;
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int (*init)(struct hwrng *rng);
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void (*cleanup)(struct hwrng *rng);
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int (*data_present)(struct hwrng *rng, int wait);
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int (*data_read)(struct hwrng *rng, u32 *data);
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int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
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unsigned long priv;
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unsigned short quality;
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/* internal. */
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struct list_head list;
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struct kref ref;
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struct completion cleanup_done;
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struct completion dying;
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};
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struct device;
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/** Register a new Hardware Random Number Generator driver. */
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extern int hwrng_register(struct hwrng *rng);
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extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
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/** Unregister a Hardware Random Number Generator driver. */
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extern void hwrng_unregister(struct hwrng *rng);
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extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
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extern long hwrng_msleep(struct hwrng *rng, unsigned int msecs);
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#endif /* LINUX_HWRANDOM_H_ */
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