On Thu, Jun 4, 2015 at 1:34 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Thu, Jun 04, 2015 at 01:11:48PM +0530, Navin P wrote: >> On Thu, Jun 4, 2015 at 10:47 AM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: >> > On Thu, Jun 04, 2015 at 09:52:08AM +0530, Navin P wrote: >> >> Hi, >> >> >> >> I want to change the cmdline of a process to support 8096 . It works >> >> well on ppc where the page size is 65k. >> >> But when i try to increase it on x86 (i686) >> >> >> >> http://lxr.free-electrons.com/source/fs/proc/base.c by doing >> >> 6*PAGE_SIZE, i get kernel panic after some time >> >> >> >> 199 static int proc_pid_cmdline(struct seq_file *m, struct pid_namespace *ns, >> >> 200 struct pid *pid, struct task_struct *task) >> >> 201 { >> >> 202 /* >> >> 203 * Rely on struct seq_operations::show() being called once >> >> 204 * per internal buffer allocation. See single_open(), traverse(). >> >> 205 */ >> >> 206 BUG_ON(m->size < PAGE_SIZE); >> >> 207 m->count += get_cmdline(task, m->buf, 6*PAGE_SIZE); >> >> 208 return 0; >> >> 209 } >> >> 210 >> > >> > That shows you that this will not work, sorry. >> >> Can you please help me and guide me into achieving this ? > > Why do you want this? What problem are you trying to solve that you > have come to the conclusion that increasing the size of the command line > is the solution? > I'm trying to learn things so that default cmd linux across all distributions for ia64 and ppc which has PAGE_SIZE has 64k works . We have this 3rd party application with deeply mounted dir that runs as a testcase more than 5k chars . We can change it , i thought if that was the problem ? So just trying to learn. I tried changing the PAGE_SHIFT but that made the kernel non-bootable or stuck at booting. This panics only when you access the pid with more than 4k chars. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
