Hello, Jan.
Thank you for your reply.
On Mon, May 03, 2004 at 23:09:38 +0200, Jan Hudec wrote:
> Every function in fs/*.c has known calling rules that state, whether it
> can be called in interrupt (either (1) or (2)) context or not. If it
> can, it must never use current.
I made hooks (that refer to 'current') inside the following functions.
fs/exec.c
do_execve()
sys_uselib()
fs/open.c
filp_open()
do_sys_truncate()
sys_chroot()
fs/namei.c
open_namei()
sys_mknod()
sys_mkdir()
sys_rmdir()
sys_unlink()
sys_symlink()
sys_link()
do_rename()
link_path_walk()
fs/namespace.c
sys_mount()
sys_pivot_root()
I have LXR(linux cross references) of kernel source 2.4.26,
so I can check from where the functions listed above are called.
But I can't determine the caller function is a interrupt handler or not.
If there is a rule (for example, functions with suffix "_no_current"
must not refer to current, and functions without suffix "_no_current" may
refer to current), I can determine.
I think functions with prefix "sys_" may refer to current.
Also, I think functions which use semaphore operations may refer to current,
but I'm not sure.
> Either the function should do something with current -- and must not be
> called in interrupt context (which you may check, if you want to be sure
> -- BUG_ON(in_interrupt())), or it does not do anything to current (nor
> any other things forbidden in interrupt) and can be called there.
If in_interrupt() always returns 0 even when interrupts are disabled by
spin_lock_irqsave() (or something else) during the state (3), I can manage
by "Just leave from the hook functions if in_interrupt() returns non-zero".
Thank you.
--
Tetsuo (a5497108 _at_ anet.ne.jp)
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