On Thu, Aug 11, 2011 at 1:50 PM, Jeff Haran <jharan@xxxxxxxxxxxxxx> wrote: >> -----Original Message----- >> From: kernelnewbies-bounces@xxxxxxxxxxxxxxxxx [mailto:kernelnewbies- >> bounces@xxxxxxxxxxxxxxxxx] On Behalf Of william douglas >> Sent: Thursday, August 11, 2011 1:23 PM >> To: kernelnewbies@xxxxxxxxxxxxxxxxx >> Subject: SYSLOG_ACTION_READ_ALL question >> >> Hello all, >> >> I'm trying to figure out why the do_syslog code in kernel/printk.c is >> using put_user instead of copy_to_user. >> > > I *THINK* this has something to do with copy_to_user not being > well-behaved in other than process context and since printk() gets > called in all contexts, it wouldn't be a safe operation. > But don't take my word for it. > > Well from what I understand, copy_to_user doesn't work in interrupt context for example as there is no user space necessarily to copy to. In this case we have a __user buffer to copy back to and __copy_to_user looks sane for the work load so I'm still unsure. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
