Rework r276532 a bit. Always avoid recursing into the console drivers
clients, hence they might not handle it very well. This change allows debugging mutex problems with kernel console drivers when "debug.witness.skipspin=0" is set in the boot environment. MFC after: 1 week
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parent
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commit
04a8159ddf
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=276626
@ -512,6 +512,13 @@ cnputs(char *p)
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int unlock_reqd = 0;
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if (use_cnputs_mtx) {
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/*
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* NOTE: Debug prints and/or witness printouts in
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* console driver clients can cause the "cnputs_mtx"
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* mutex to recurse. Simply return if that happens.
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*/
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if (mtx_owned(&cnputs_mtx))
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return;
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mtx_lock_spin(&cnputs_mtx);
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unlock_reqd = 1;
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}
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@ -601,13 +608,7 @@ static void
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cn_drvinit(void *unused)
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{
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/*
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* NOTE: Debug prints and/or witness printouts in console
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* driver clients can cause the "cnputs_mtx" mutex to
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* recurse. Make sure the "MTX_RECURSE" flags is set!
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*/
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mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN |
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MTX_NOWITNESS | MTX_RECURSE);
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mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
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use_cnputs_mtx = 1;
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}
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