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Subject: Re: [linux-dvb] [DVB] PATCH: Handling failure of dvb_frontend_start in dvb_frontend_open [2.5.69-70] Date: Fri, 6 Jun 2003 15:28:24 +0200 From: Daniele Bellucci <[EMAIL PROTECTED]> To: Johannes Stezenbach <[EMAIL PROTECTED]> On Fri 6 June 2003 15:03, Johannes Stezenbach wrote: > Hi, > > Daniele Bellucci wrote: > > This patch applies both to 2.5.69 and to 2.5.70 > > ... > > > + * Changes: > > + * 03/06/2003: handling failure of dvb_frontend_start in > > dvb_frontend_open + * Daniele Bellucci > > <[EMAIL PROTECTED]>. > > [snip] > > I made similar changes to dvb-frontend.c some weeks ago. It's > unfortunate that it takes so much time until they get merged into > Linus' kernel tree. > > Anyway, I would like to know why dvb_frontend_start() would fail > for you. > > > > The only reason it failed for me was when running the program > that open()s the frontend in the debugger, which leads to > kernel_thread() failure for 2.4.21-rc? since the time the ptrace() exploit > fixes have been merged. > > > Regards, > Johannes Hi Johannes, there are many reason for kernel_thread to fail ... like: the allocation of a new struct task_struct (its descriptor) may fail (look at dup_task_struct in kernel/fork.c) security_task_create (kernel/fork.c: copy_process) can forbid the creation of a new task (in 2.5.x) if the actual number of threads is > of max_threads (kernel/fork.c: copy_process) and so on... kernel_thread call do_fork, then do_fork call copy_process.. there are many cases for copy_process to fail. You should look at copy_process. ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- --- PGP PKEY http://pgp.mit.edu:11371/pks/[EMAIL PROTECTED]&op=index ICQ# 104896040 Netphone/Fax 178.605.7063 Homepage http://web.tiscali.it/bellucda ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- --- Daniele Bellucci ------------------------------------------------------- -- ------------------------------------------------------------------------------------------------------------------------------------------------------------- PGP PKEY http://pgp.mit.edu:11371/pks/[EMAIL PROTECTED]&op=index ICQ# 104896040 Netphone/Fax 178.605.7063 Homepage http://web.tiscali.it/bellucda ------------------------------------------------------------------------------------------------------------------------------------------------------------- Daniele Bellucci -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe linux-dvb" as subject.
