Fix a deadlock if a panic happens during request handling #6920
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During request handling, if a panic is created, deferred functions are run but otherwise execution stops. #5889 changed some locks to non-defers but had the side effect of causing the read lock to not be released if the request panicked. This fixes that and addresses a few other potential places where things could go wrong: 1) In sealInitCommon we always now defer a function that unlocks the read lock if it hasn't been unlocked already 2) In StepDown we defer the RUnlock but we also had two error cases that were calling it manually. These are unlikely to be hit but if they were I believe would cause a panic.
briankassouf
previously approved these changes
Jun 19, 2019
vishalnayak
reviewed
Jun 19, 2019
| @@ -261,14 +262,12 @@ func (c *Core) StepDown(httpCtx context.Context, req *logical.Request) (retErr e | |||
| if entity != nil && entity.Disabled { | |||
| c.logger.Warn("permission denied as the entity on the token is disabled") | |||
| retErr = multierror.Append(retErr, logical.ErrPermissionDenied) | |||
| c.stateLock.RUnlock() | |||
kalafut
previously approved these changes
Jun 19, 2019
vishalnayak
previously approved these changes
Jun 19, 2019
jefferai
dismissed stale reviews from vishalnayak, kalafut, and briankassouf
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* Fix a deadlock if a panic happens during request handling During request handling, if a panic is created, deferred functions are run but otherwise execution stops. #5889 changed some locks to non-defers but had the side effect of causing the read lock to not be released if the request panicked. This fixes that and addresses a few other potential places where things could go wrong: 1) In sealInitCommon we always now defer a function that unlocks the read lock if it hasn't been unlocked already 2) In StepDown we defer the RUnlock but we also had two error cases that were calling it manually. These are unlikely to be hit but if they were I believe would cause a panic. * Add panic recovery test
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During request handling, if a panic is created, deferred functions are
run but otherwise execution stops. #5889 changed some locks to
non-defers but had the side effect of causing the read lock to not be
released if the request panicked. This fixes that and addresses a few
other potential places where things could go wrong:
read lock if it hasn't been unlocked already
were calling it manually. These are unlikely to be hit but if they were
I believe would cause a panic.