* Re: [uml-devel] [patch 094/241] uml: fix error output during early boot [not found] <200702100944.l1A9iSEp008813@shell0.pdx.osdl.net> @ 2007-02-10 12:31 ` Blaisorblade 2007-02-10 22:21 ` Jeff Dike 0 siblings, 1 reply; 3+ messages in thread From: Blaisorblade @ 2007-02-10 12:31 UTC (permalink / raw) To: user-mode-linux-devel; +Cc: Jeff Dike On Saturday 10 February 2007 10:44, akpm@linux-foundation.org wrote: > From: Jeff Dike <jdike@addtoit.com> > > The startup code panics a lot if anything goes wrong early on. This is > wrong for several reasons, like the kernel isn't running, so you can't > really be calling into it yet, but the harm comes from useful error > messages being trapped in the printk ring where no one will ever see them. > > This patch changes these panics to perror and printf in wrappers which also > exit. Normal, informational, prints are also wrapped so that > fflush(stdout) is called after each one. This is so the output appears in > the correct sequence in the event of an error. libc's printf has an enormous stack usage, so that my_printf is used for direct output instead of printf; if this is ok because it's bootup code, then *fatal* should be marked as "bootup code only"; otherwise we may reuse vsprintf() and write() or fputs(); this should match what happens in my_printf, to avoid any unlikely problem with libc's buffering. -- Inform me of my mistakes, so I can add them to my list! Paolo Giarrusso, aka Blaisorblade http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [uml-devel] [patch 094/241] uml: fix error output during early boot 2007-02-10 12:31 ` [uml-devel] [patch 094/241] uml: fix error output during early boot Blaisorblade @ 2007-02-10 22:21 ` Jeff Dike 2007-02-12 18:59 ` Blaisorblade 0 siblings, 1 reply; 3+ messages in thread From: Jeff Dike @ 2007-02-10 22:21 UTC (permalink / raw) To: Blaisorblade; +Cc: user-mode-linux-devel On Sat, Feb 10, 2007 at 01:31:20PM +0100, Blaisorblade wrote: > libc's printf has an enormous stack usage, so that my_printf is used for > direct output instead of printf; if this is ok because it's bootup > code, It is bootup code only. > then *fatal* should be marked as "bootup code only"; OK. > otherwise > we may reuse vsprintf() and write() or fputs(); this should match > what happens in my_printf, to avoid any unlikely problem with libc's > buffering. Offhand, I would say that if we are on a kernel stack, printk is safe to use, and should be used, so there's no need for things like my_printf. Maybe there are some exceptions in early boot when the kernel is running, but before the console is working, but I can't think of any problems we've had like that. Jeff -- Work email - jdike at linux dot intel dot com ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [uml-devel] [patch 094/241] uml: fix error output during early boot 2007-02-10 22:21 ` Jeff Dike @ 2007-02-12 18:59 ` Blaisorblade 0 siblings, 0 replies; 3+ messages in thread From: Blaisorblade @ 2007-02-12 18:59 UTC (permalink / raw) To: Jeff Dike; +Cc: user-mode-linux-devel On Saturday 10 February 2007 23:21, Jeff Dike wrote: > On Sat, Feb 10, 2007 at 01:31:20PM +0100, Blaisorblade wrote: > > libc's printf has an enormous stack usage, so that my_printf is used for > > direct output instead of printf; if this is ok because it's bootup > > code, > > It is bootup code only. > > > then *fatal* should be marked as "bootup code only"; > > OK. > > > otherwise > > we may reuse vsprintf() and write() or fputs(); this should match > > what happens in my_printf, to avoid any unlikely problem with libc's > > buffering. > > Offhand, I would say that if we are on a kernel stack, printk is safe > to use, and should be used, so there's no need for things like > my_printf. Maybe there are some exceptions in early boot when the > kernel is running, but before the console is working, but I can't > think of any problems we've had like that. It's for no_config_chan (don't recall the right name), i.e. for when the console will never work because of a misconfiguration. Indeed it's static (and otherwise it ought to have a better name!). -- Inform me of my mistakes, so I can add them to my list! Paolo Giarrusso, aka Blaisorblade http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-02-12 18:59 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <200702100944.l1A9iSEp008813@shell0.pdx.osdl.net> 2007-02-10 12:31 ` [uml-devel] [patch 094/241] uml: fix error output during early boot Blaisorblade 2007-02-10 22:21 ` Jeff Dike 2007-02-12 18:59 ` Blaisorblade
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