UPSTREAM: random: fix soft lockup when trying to read from an uninitialized blocking pool
Fixes: eb9d1bf079bb: "random: only read from /dev/random after its pool has received 128 bits" Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> (cherry picked from commit 58be0106c5306b939b07b4b8bf00669a20593f4b) Signed-off-by: Mark Salyzyn <salyzyn@google.com> Bug: 148665638 Change-Id: I87df025423848df2e8ff2ccb6856da073a385750
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1 changed files with 13 additions and 3 deletions
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@ -772,8 +772,11 @@ retry:
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if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
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goto retry;
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if (has_initialized)
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if (has_initialized) {
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r->initialized = 1;
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wake_up_interruptible(&random_read_wait);
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kill_fasync(&fasync, SIGIO, POLL_IN);
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}
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trace_credit_entropy_bits(r->name, nbits,
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entropy_count >> ENTROPY_SHIFT, _RET_IP_);
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@ -789,6 +792,13 @@ retry:
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entropy_bits = r->entropy_count >> ENTROPY_SHIFT;
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}
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/* initialize the blocking pool if necessary */
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if (entropy_bits >= random_read_wakeup_bits &&
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!other->initialized) {
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schedule_work(&other->push_work);
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return;
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}
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/* should we wake readers? */
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if (entropy_bits >= random_read_wakeup_bits &&
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wq_has_sleeper(&random_read_wait)) {
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@ -1996,8 +2006,8 @@ _random_read(int nonblock, char __user *buf, size_t nbytes)
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return -EAGAIN;
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wait_event_interruptible(random_read_wait,
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ENTROPY_BITS(&input_pool) >=
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random_read_wakeup_bits);
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blocking_pool.initialized &&
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(ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits));
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if (signal_pending(current))
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return -ERESTARTSYS;
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}
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