| Message ID | 20140916023736.49db964e@as (mailing list archive) |
|---|---|
| State | Awaiting Upstream, archived |
| Headers | show |
Hi Chuck, On 16/09/14 08:37, Chuck Ebbert wrote: > static inline unsigned long *end_of_stack(struct task_struct *p) > { > +#ifdef CONFIG_STACK_GROWSUP > + return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1; Nit: this line should probably be wrapped to 80 columns. Other than that, I've tested this on metag and can confirm that it fixes the following BUG which you would otherwise get during boot with Aaron's patches: BUG: failure at kernel/sched/core.c:2664/schedule_debug()! Kernel panic - not syncing: BUG! Tested-by: James Hogan <james.hogan@imgtec.com> [metag] Acked-by: James Hogan <james.hogan@imgtec.com> Aaron: please can you try to get this patch applied before your patch series. Thanks James -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Sep 19, 2014 at 12:21:37PM +0100, James Hogan wrote: > Hi Chuck, > > On 16/09/14 08:37, Chuck Ebbert wrote: > > static inline unsigned long *end_of_stack(struct task_struct *p) > > { > > +#ifdef CONFIG_STACK_GROWSUP > > + return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1; > > Nit: this line should probably be wrapped to 80 columns. > > Other than that, I've tested this on metag and can confirm that it fixes > the following BUG which you would otherwise get during boot with Aaron's > patches: > > BUG: failure at kernel/sched/core.c:2664/schedule_debug()! > Kernel panic - not syncing: BUG! > > Tested-by: James Hogan <james.hogan@imgtec.com> [metag] > Acked-by: James Hogan <james.hogan@imgtec.com> OK. Acked-by: Aaron Tomlin <atomlin@redhat.com> > Aaron: please can you try to get this patch applied before your patch > series. Ingo, I hope it's not too late to get this patch in (once the nit has been addressed) for CONFIG_STACK_GROWSUP? Regards,
diff a/include/linux/sched.h b/include/linux/sched.h --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2610,7 +2610,11 @@ static inline void setup_thread_stack(struct task_struct *p, struct task_struct static inline unsigned long *end_of_stack(struct task_struct *p) { +#ifdef CONFIG_STACK_GROWSUP + return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1; +#else return (unsigned long *)(task_thread_info(p) + 1); +#endif } #endif
Aaron Tomlin recently posted patches [1] to enable checking the stack canary on every task switch. Looking at the canary code, I realized that every arch (except ia64, which adds some space for register spill above the stack) shares a definition of end_of_stack() that makes it the first long after the threadinfo. For stacks that grow down, this low address is correct because the stack starts at the end of the thread area and grows toward lower addresses. However, for stacks that grow up, toward higher addresses, this is wrong. (The stack actually grows away from the canary.) On these archs end_of_stack() should return the address of the last long, at the highest possible address for the stack. [1] http://lkml.org/lkml/2014/9/12/293 Signed-off-by: Chuck Ebbert <cebbert.lkml@gmail.com> --- Compile tested only, with Aaron's patches applied and the new option CONFIG_SCHED_STACK_END_CHECK they add enabled. I have no way to test this any further. -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html