* Fwd: arch/ && tracehook_report_syscall_xxx()
2009-04-29 19:08 ` Fwd: arch/ && tracehook_report_syscall_xxx() Oleg Nesterov
@ 2009-04-29 19:08 ` Oleg Nesterov
2009-04-29 19:17 ` Roland McGrath
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Oleg Nesterov @ 2009-04-29 19:08 UTC (permalink / raw)
To: Christoph Hellwig, chris, cooloney, deller, geert, gerg,
hskinnemoen, jdike, jesper.nilsson, kyle, linux, ralf, rth,
starvik, takata, ysato, zippel
Cc: Roland McGrath, linux-kernel, linux-arch
On 04/27, Christoph Hellwig wrote:
>
> I've poked a few arch maintainers in the past to separate the enter/exit
> path and usually got the desired changes :)
I'd like to try your method!
So. Dear maintainers of
alpha
arm
avr32
blackfin
cris
h8300
m32r
m68k
m68knommu
mips
parisc
um
xtensa
. Could you please convert your syscall trace code to use
tracehook_report_syscall_entry/tracehook_report_syscall_exit ?
For example, let's look at more or less typical arch/alpha/kernel/ptrace.c,
asmlinkage void
syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/* The 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* This isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
it would be really nice to turn it into something like
asmlinkage void
syscall_trace(int entryexit)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (entryexit)
tracehook_report_syscall_entry(task_pt_regs(current));
else
tracehook_report_syscall_exit(task_pt_regs(current), stepping);
}
Also, tracehook_report_syscall_entry() might want to abort this system
call (please see the comment above this helper), it would be great to
take the returned value into account.
arch/* play with ptrace internals which should be changed soon, not good.
Thanks!
Oleg.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Fwd: arch/ && tracehook_report_syscall_xxx()
2009-04-29 19:08 ` Fwd: arch/ && tracehook_report_syscall_xxx() Oleg Nesterov
2009-04-29 19:08 ` Oleg Nesterov
@ 2009-04-29 19:17 ` Roland McGrath
2009-04-29 19:30 ` Ingo Molnar
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Roland McGrath @ 2009-04-29 19:17 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Christoph Hellwig, chris, cooloney, deller, geert, gerg,
hskinnemoen, jdike, jesper.nilsson, kyle, linux, ralf, rth,
starvik, takata, ysato, zippel, linux-kernel, linux-arch
Christoph has already poked everyone, I believe.
> it would be really nice to turn it into something like
>
> asmlinkage void
> syscall_trace(int entryexit)
We recommend replacing this with separate entry/exit paths from the
assembly code, if you are changing arch code anyway.
Thanks,
Roland
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Fwd: arch/ && tracehook_report_syscall_xxx()
2009-04-29 19:08 ` Fwd: arch/ && tracehook_report_syscall_xxx() Oleg Nesterov
2009-04-29 19:08 ` Oleg Nesterov
2009-04-29 19:17 ` Roland McGrath
@ 2009-04-29 19:30 ` Ingo Molnar
2009-04-29 19:44 ` Christoph Hellwig
2009-04-29 19:53 ` Kyle McMartin
4 siblings, 0 replies; 6+ messages in thread
From: Ingo Molnar @ 2009-04-29 19:30 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Christoph Hellwig, chris, cooloney, deller, geert, gerg,
hskinnemoen, jdike, jesper.nilsson, kyle, linux, ralf, rth,
starvik, takata, ysato, zippel, Roland McGrath, linux-kernel,
linux-arch
* Oleg Nesterov <oleg@redhat.com> wrote:
> On 04/27, Christoph Hellwig wrote:
> >
> > I've poked a few arch maintainers in the past to separate the enter/exit
> > path and usually got the desired changes :)
>
> I'd like to try your method!
>
> So. Dear maintainers of
>
> alpha
> arm
> avr32
> blackfin
> cris
> h8300
> m32r
> m68k
> m68knommu
> mips
> parisc
> um
> xtensa
>
> . Could you please convert your syscall trace code to use
> tracehook_report_syscall_entry/tracehook_report_syscall_exit ?
>
>
> For example, let's look at more or less typical arch/alpha/kernel/ptrace.c,
>
> asmlinkage void
> syscall_trace(void)
> {
> if (!test_thread_flag(TIF_SYSCALL_TRACE))
> return;
> if (!(current->ptrace & PT_PTRACED))
> return;
> /* The 0x80 provides a way for the tracing parent to distinguish
> between a syscall stop and SIGTRAP delivery */
> ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
> ? 0x80 : 0));
>
> /*
> * This isn't the same as continuing with a signal, but it will do
> * for normal use. strace only continues with a signal if the
> * stopping signal is not SIGTRAP. -brl
> */
> if (current->exit_code) {
> send_sig(current->exit_code, current, 1);
> current->exit_code = 0;
> }
> }
>
> it would be really nice to turn it into something like
>
> asmlinkage void
> syscall_trace(int entryexit)
> {
> if (!test_thread_flag(TIF_SYSCALL_TRACE))
> return;
>
> if (entryexit)
> tracehook_report_syscall_entry(task_pt_regs(current));
> else
> tracehook_report_syscall_exit(task_pt_regs(current), stepping);
> }
>
> Also, tracehook_report_syscall_entry() might want to abort this system
> call (please see the comment above this helper), it would be great to
> take the returned value into account.
>
> arch/* play with ptrace internals which should be changed soon, not good.
And there's upstream examples in:
arch/ia64/kernel/ptrace.c
arch/powerpc/kernel/ptrace.c
arch/s390/kernel/ptrace.c
arch/sh/kernel/ptrace_32.c
arch/sh/kernel/ptrace_64.c
arch/sparc/kernel/ptrace_32.c
arch/sparc/kernel/ptrace_64.c
arch/x86/kernel/ptrace.c
as well, for tracehook usage. Chances are that your architecture's
syscall entry/exit ptrace hooks look quite similar to one of the
architectures above!
Ingo
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Fwd: arch/ && tracehook_report_syscall_xxx()
2009-04-29 19:08 ` Fwd: arch/ && tracehook_report_syscall_xxx() Oleg Nesterov
` (2 preceding siblings ...)
2009-04-29 19:30 ` Ingo Molnar
@ 2009-04-29 19:44 ` Christoph Hellwig
2009-04-29 19:53 ` Kyle McMartin
4 siblings, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2009-04-29 19:44 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Christoph Hellwig, chris, cooloney, deller, geert, gerg,
hskinnemoen, jdike, jesper.nilsson, kyle, linux, ralf, rth,
starvik, takata, ysato, zippel, Roland McGrath, linux-kernel,
linux-arch
On Wed, Apr 29, 2009 at 09:08:52PM +0200, Oleg Nesterov wrote:
> . Could you please convert your syscall trace code to use
> tracehook_report_syscall_entry/tracehook_report_syscall_exit ?
This is part of Roland's step by step cookbook for new-style ptrace,
so we should have most done. Is there anything that makes this more
urgent than the others steps for you?
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Fwd: arch/ && tracehook_report_syscall_xxx()
2009-04-29 19:08 ` Fwd: arch/ && tracehook_report_syscall_xxx() Oleg Nesterov
` (3 preceding siblings ...)
2009-04-29 19:44 ` Christoph Hellwig
@ 2009-04-29 19:53 ` Kyle McMartin
4 siblings, 0 replies; 6+ messages in thread
From: Kyle McMartin @ 2009-04-29 19:53 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Christoph Hellwig, chris, cooloney, deller, geert, gerg,
hskinnemoen, jdike, jesper.nilsson, kyle, linux, ralf, rth,
starvik, takata, ysato, zippel, Roland McGrath, linux-kernel,
linux-arch
On Wed, Apr 29, 2009 at 09:08:52PM +0200, Oleg Nesterov wrote:
> So. Dear maintainers of
>
> parisc
>
> . Could you please convert your syscall trace code to use
> tracehook_report_syscall_entry/tracehook_report_syscall_exit ?
>
I've got this mostly completed and working on parisc (at least, gdb
and strace continue working, so I'm happy with that result... :)
I'll probably push it for .30 since it seems harmless.
--Kyle
^ permalink raw reply [flat|nested] 6+ messages in thread