Date: Sun, 2 Nov 2014 21:20:57 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Adrian Chadd <adrian@freebsd.org> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, Ian Lepore <ian@freebsd.org>, Mark R V Murray <mark@grondar.org> Subject: Re: svn commit: r273958 - head/sys/dev/random Message-ID: <20141102192057.GB53947@kib.kiev.ua> In-Reply-To: <CAJ-VmomeOwE3LOpehhJ__G=FCoBDRXrrn%2BSfjwPFODts6YYHNQ@mail.gmail.com> References: <201411020201.sA221unt091493@svn.freebsd.org> <720EB74E-094A-43F3-8B1C-47BC7F6FECC3@grondar.org> <1414934579.17308.248.camel@revolution.hippie.lan> <6FB65828-6A79-4BDE-A9F7-BC472BA538CE@grondar.org> <CAJ-VmomeOwE3LOpehhJ__G=FCoBDRXrrn%2BSfjwPFODts6YYHNQ@mail.gmail.com>
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On Sun, Nov 02, 2014 at 11:05:27AM -0800, Adrian Chadd wrote: > [snip all the conversation] > > Ok. There's still a problem that I can trigger by trying to Ctrl-C a > process that's blocked reading for randomness. I'll try to chase up > more details about and file a PR about it. > > The unfortunate part is that the kernel side stack trace of the > offending / hung process isn't currently helpful. :( > >From what I see, signals are essentially ignored in the read code. See random_adaptors.c:random_adaptor_read(): /* Sleep instead of going into a spin-frenzy */ tsleep(&random_adaptor, PUSER | PCATCH, "block", hz/10); The error which would indicate the signal catch, is dropped. Also, unbound sleep does not drop random_adaptor_lock, which means that you cannot module which could provide some more randomness for you, while any thread is stuck in read loop.
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