* [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT
@ 2020-06-20 10:41 Mike Rapoport
2020-06-24 10:20 ` Mike Rapoport
2020-06-27 22:12 ` Steven Rostedt
0 siblings, 2 replies; 4+ messages in thread
From: Mike Rapoport @ 2020-06-20 10:41 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
Dietmar Eggemann, Steven Rostedt, Ben Segall, Mel Gorman,
Mike Rapoport
From: Mike Rapoport <rppt@linux.ibm.com>
Since the commit a148866489fb ("sched: Replace rq::wake_list")
task_struct and CSD_TYPE_TTWU objects can be on the same queue and this
requires that have "layout similar enough".
This assumption is broken when CONFIG_GCC_PLUGIN_RANDSTRUCT is enabled:
CHK include/generated/compile.h
CC kernel/smp.o
In file included from arch/x86/include/asm/atomic.h:5,
from include/linux/atomic.h:7,
from include/linux/llist.h:51,
from include/linux/irq_work.h:5,
from kernel/smp.c:10:
kernel/smp.c: In function ‘smp_init’:
include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_157’ declared with attribute error: BUILD_BUG_ON failed: offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) != offsetof(struct __call_single_data, flags) - offsetof(struct __call_single_data, llist)
392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
373 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
| ^~~~~~~~~~~~~~~~
kernel/smp.c:687:2: note: in expansion of macro ‘BUILD_BUG_ON’
687 | BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) !=
| ^~~~~~~~~~~~
make[2]: *** [scripts/Makefile.build:280: kernel/smp.o] Error 1
make[1]: *** [Makefile:1764: kernel] Error 2
make[1]: *** Waiting for unfinished jobs....
make[1]: Leaving directory '/home/mike/build/kernel'
make: *** [Makefile:185: __sub-make] Error 2
Move 'wake_entry' and 'wake_entry_type' fiels of task_struct out of the
randomized fields to keep their layout intact.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
include/linux/sched.h | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b62e6aaf28f0..c885573669ac 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -641,6 +641,15 @@ struct task_struct {
/* -1 unrunnable, 0 runnable, >0 stopped: */
volatile long state;
+ /*
+ * The layout of these fields must match the layout CSD_TYPE_TTWU
+ * so they can be on the same the @call_single_queue
+ */
+#ifdef CONFIG_SMP
+ struct llist_node wake_entry;
+ unsigned int wake_entry_type;
+#endif
+
/*
* This begins the randomizable portion of task_struct. Only
* scheduling-critical items should be added above here.
@@ -654,8 +663,6 @@ struct task_struct {
unsigned int ptrace;
#ifdef CONFIG_SMP
- struct llist_node wake_entry;
- unsigned int wake_entry_type;
int on_cpu;
#ifdef CONFIG_THREAD_INFO_IN_TASK
/* Current CPU: */
--
2.25.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT
2020-06-20 10:41 [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT Mike Rapoport
@ 2020-06-24 10:20 ` Mike Rapoport
2020-06-27 22:12 ` Steven Rostedt
1 sibling, 0 replies; 4+ messages in thread
From: Mike Rapoport @ 2020-06-24 10:20 UTC (permalink / raw)
To: linux-kernel
Cc: Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
Dietmar Eggemann, Steven Rostedt, Ben Segall, Mel Gorman,
Mike Rapoport
ping?
On Sat, Jun 20, 2020 at 01:41:36PM +0300, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Since the commit a148866489fb ("sched: Replace rq::wake_list")
> task_struct and CSD_TYPE_TTWU objects can be on the same queue and this
> requires that have "layout similar enough".
>
> This assumption is broken when CONFIG_GCC_PLUGIN_RANDSTRUCT is enabled:
>
> CHK include/generated/compile.h
> CC kernel/smp.o
> In file included from arch/x86/include/asm/atomic.h:5,
> from include/linux/atomic.h:7,
> from include/linux/llist.h:51,
> from include/linux/irq_work.h:5,
> from kernel/smp.c:10:
> kernel/smp.c: In function ‘smp_init’:
> include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_157’ declared with attribute error: BUILD_BUG_ON failed: offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) != offsetof(struct __call_single_data, flags) - offsetof(struct __call_single_data, llist)
> 392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> | ^
> include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
> 373 | prefix ## suffix(); \
> | ^~~~~~
> include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
> 392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> | ^~~~~~~~~~~~~~~~~~~
> include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
> 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> | ^~~~~~~~~~~~~~~~~~
> include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
> 50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
> | ^~~~~~~~~~~~~~~~
> kernel/smp.c:687:2: note: in expansion of macro ‘BUILD_BUG_ON’
> 687 | BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) !=
> | ^~~~~~~~~~~~
> make[2]: *** [scripts/Makefile.build:280: kernel/smp.o] Error 1
> make[1]: *** [Makefile:1764: kernel] Error 2
> make[1]: *** Waiting for unfinished jobs....
> make[1]: Leaving directory '/home/mike/build/kernel'
> make: *** [Makefile:185: __sub-make] Error 2
>
> Move 'wake_entry' and 'wake_entry_type' fiels of task_struct out of the
> randomized fields to keep their layout intact.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> include/linux/sched.h | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index b62e6aaf28f0..c885573669ac 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -641,6 +641,15 @@ struct task_struct {
> /* -1 unrunnable, 0 runnable, >0 stopped: */
> volatile long state;
>
> + /*
> + * The layout of these fields must match the layout CSD_TYPE_TTWU
> + * so they can be on the same the @call_single_queue
> + */
> +#ifdef CONFIG_SMP
> + struct llist_node wake_entry;
> + unsigned int wake_entry_type;
> +#endif
> +
> /*
> * This begins the randomizable portion of task_struct. Only
> * scheduling-critical items should be added above here.
> @@ -654,8 +663,6 @@ struct task_struct {
> unsigned int ptrace;
>
> #ifdef CONFIG_SMP
> - struct llist_node wake_entry;
> - unsigned int wake_entry_type;
> int on_cpu;
> #ifdef CONFIG_THREAD_INFO_IN_TASK
> /* Current CPU: */
> --
> 2.25.4
>
--
Sincerely yours,
Mike.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT
2020-06-20 10:41 [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT Mike Rapoport
2020-06-24 10:20 ` Mike Rapoport
@ 2020-06-27 22:12 ` Steven Rostedt
2020-06-28 6:44 ` Mike Rapoport
1 sibling, 1 reply; 4+ messages in thread
From: Steven Rostedt @ 2020-06-27 22:12 UTC (permalink / raw)
To: Mike Rapoport
Cc: linux-kernel, Ingo Molnar, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Ben Segall, Mel Gorman,
Mike Rapoport, Kees Cook
On Sat, 20 Jun 2020 13:41:36 +0300
Mike Rapoport <rppt@kernel.org> wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Since the commit a148866489fb ("sched: Replace rq::wake_list")
> task_struct and CSD_TYPE_TTWU objects can be on the same queue and this
> requires that have "layout similar enough".
>
> This assumption is broken when CONFIG_GCC_PLUGIN_RANDSTRUCT is enabled:
You forgot to Cc Kees, who's the one that is probably the most
concerned about randomizing structures!
>
> CHK include/generated/compile.h
> CC kernel/smp.o
> In file included from arch/x86/include/asm/atomic.h:5,
> from include/linux/atomic.h:7,
> from include/linux/llist.h:51,
> from include/linux/irq_work.h:5,
> from kernel/smp.c:10:
> kernel/smp.c: In function ‘smp_init’:
> include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_157’ declared with attribute error: BUILD_BUG_ON failed: offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) != offsetof(struct __call_single_data, flags) - offsetof(struct __call_single_data, llist)
> 392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> | ^
> include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
> 373 | prefix ## suffix(); \
> | ^~~~~~
> include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
> 392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> | ^~~~~~~~~~~~~~~~~~~
> include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
> 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> | ^~~~~~~~~~~~~~~~~~
> include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
> 50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
> | ^~~~~~~~~~~~~~~~
> kernel/smp.c:687:2: note: in expansion of macro ‘BUILD_BUG_ON’
> 687 | BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) !=
> | ^~~~~~~~~~~~
> make[2]: *** [scripts/Makefile.build:280: kernel/smp.o] Error 1
> make[1]: *** [Makefile:1764: kernel] Error 2
> make[1]: *** Waiting for unfinished jobs....
> make[1]: Leaving directory '/home/mike/build/kernel'
> make: *** [Makefile:185: __sub-make] Error 2
Seems the dependency is that the offsets between wake_entry and
wake_entry_type doesn't change.
>
> Move 'wake_entry' and 'wake_entry_type' fiels of task_struct out of
> the randomized fields to keep their layout intact.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> include/linux/sched.h | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index b62e6aaf28f0..c885573669ac 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -641,6 +641,15 @@ struct task_struct {
> /* -1 unrunnable, 0 runnable, >0 stopped: */
> volatile long state;
>
> + /*
> + * The layout of these fields must match the layout
> CSD_TYPE_TTWU
> + * so they can be on the same the @call_single_queue
> + */
> +#ifdef CONFIG_SMP
> + struct llist_node wake_entry;
> + unsigned int wake_entry_type;
> +#endif
> +
> /*
> * This begins the randomizable portion of task_struct. Only
> * scheduling-critical items should be added above here.
> @@ -654,8 +663,6 @@ struct task_struct {
> unsigned int ptrace;
>
> #ifdef CONFIG_SMP
> - struct llist_node wake_entry;
> - unsigned int wake_entry_type;
What about instead just create an anonymous structure of the two. That
way they can still be randomized within the task struct and not be a
target of attacks?
struct {
struct llist_node wake_entry;
unsigned int wake_entry_type;
};
Would that work?
-- Steve
> int on_cpu;
> #ifdef CONFIG_THREAD_INFO_IN_TASK
> /* Current CPU: */
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT
2020-06-27 22:12 ` Steven Rostedt
@ 2020-06-28 6:44 ` Mike Rapoport
0 siblings, 0 replies; 4+ messages in thread
From: Mike Rapoport @ 2020-06-28 6:44 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, Ingo Molnar, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Ben Segall, Mel Gorman,
Mike Rapoport, Kees Cook
On Sat, Jun 27, 2020 at 06:12:14PM -0400, Steven Rostedt wrote:
> On Sat, 20 Jun 2020 13:41:36 +0300
> Mike Rapoport <rppt@kernel.org> wrote:
>
> > From: Mike Rapoport <rppt@linux.ibm.com>
> >
> > Since the commit a148866489fb ("sched: Replace rq::wake_list")
> > task_struct and CSD_TYPE_TTWU objects can be on the same queue and this
> > requires that have "layout similar enough".
> >
> > This assumption is broken when CONFIG_GCC_PLUGIN_RANDSTRUCT is enabled:
>
> You forgot to Cc Kees, who's the one that is probably the most
> concerned about randomizing structures!
I was not concerned about randomizing, I was troubled by failing
allyesconfig builds :)
> > /*
> > * This begins the randomizable portion of task_struct. Only
> > * scheduling-critical items should be added above here.
> > @@ -654,8 +663,6 @@ struct task_struct {
> > unsigned int ptrace;
> >
> > #ifdef CONFIG_SMP
> > - struct llist_node wake_entry;
> > - unsigned int wake_entry_type;
>
> What about instead just create an anonymous structure of the two. That
> way they can still be randomized within the task struct and not be a
> target of attacks?
>
> struct {
> struct llist_node wake_entry;
> unsigned int wake_entry_type;
> };
>
> Would that work?
Yep, thanks, this works.
Will send v2 soon.
> -- Steve
>
>
> > int on_cpu;
> > #ifdef CONFIG_THREAD_INFO_IN_TASK
> > /* Current CPU: */
>
--
Sincerely yours,
Mike.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-06-28 6:46 UTC | newest]
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2020-06-20 10:41 [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT Mike Rapoport
2020-06-24 10:20 ` Mike Rapoport
2020-06-27 22:12 ` Steven Rostedt
2020-06-28 6:44 ` Mike Rapoport
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