On 03/20/2015 10:29 AM, Paul E. McKenney wrote: > On Fri, Mar 20, 2015 at 10:15:34AM -0400, Sasha Levin wrote: >> On 03/15/2015 08:02 PM, Paul E. McKenney wrote: >>> On Sun, Mar 15, 2015 at 07:32:32PM -0400, Sasha Levin wrote: >>>>> On 03/15/2015 04:43 PM, Paul E. McKenney wrote: >>>>>>> But I did find a bug that would result in the other warnings, and could >>>>>>> also result in too-short grace periods, which could in turn result in >>>>>>> arbitrarily arbitrary misbehavior. The patch below, which is also on >>>>>>> its way into -next, should fix this. Please let me know how it does >>>>>>> for you. >>>>> >>>>> I've stopped seeing the warnings I've previously reported, but started >>>>> seeing a new one: >>>>> >>>>> [ 788.564596] WARNING: CPU: 12 PID: 9711 at kernel/rcu/tree.c:2201 >>>>> rcu_report_qs_rnp+0x42e/0x5a0() >>>>> [ 788.568123] Modules linked in: >>>>> [ 788.568123] CPU: 12 PID: 9711 Comm: trinity-main Not tainted >>>>> 4.0.0-rc3-next-20150313-sasha-00041-g83a3dc8-dirty #2078 >>>>> [ 788.568123] ffff8803a1ba0000 00000000400df16a ffff880442807cc8 >>>>> ffffffffb1ab01ca >>>>> [ 788.568123] 0000000000000000 0000000000000000 ffff880442807d18 >>>>> ffffffffa71e261a >>>>> [ 788.568123] dffffc0000000000 ffffffffa733d2ee ffff880442807d28 >>>>> ffffffffb4724000 >>>>> [ 788.568123] Call Trace: >>>>> [ 788.568123] <IRQ> dump_stack (lib/dump_stack.c:52) >>>>> [ 788.568123] warn_slowpath_common (kernel/panic.c:447) >>>>> [ 788.568123] ? rcu_report_qs_rnp (kernel/rcu/tree.c:2201 (discriminator >>>>> 3)) >>>>> [ 788.568123] warn_slowpath_null (kernel/panic.c:481) >>>>> [ 788.568123] rcu_report_qs_rnp (kernel/rcu/tree.c:2201 (discriminator >>>>> 3)) >>>>> [ 788.568123] rcu_process_callbacks (kernel/rcu/tree.c:2302 >>>>> kernel/rcu/tree.c:2338 kernel/rcu/tree.c:2824 kernel/rcu/tree.c:2857) >>>>> [ 788.568123] __do_softirq (kernel/softirq.c:273 >>>>> include/linux/jump_label.h:114 include/trace/events/irq.h:126 >>>>> kernel/softirq.c:274) >>>>> [ 788.568123] irq_exit (kernel/softirq.c:350 kernel/softirq.c:391) >>>>> [ 788.568123] smp_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:918) >>>>> [ 788.568123] apic_timer_interrupt (arch/x86/kernel/entry_64.S:920) >>>>> [ 788.568123] <EOI> ? mark_held_locks (kernel/locking/lockdep.c:2525) >>>>> [ 788.568123] finish_task_switch (kernel/sched/core.c:2231) >>>>> [ 788.568123] __schedule (kernel/sched/core.c:2337 >>>>> kernel/sched/core.c:2795) >>>>> [ 788.568123] schedule (./arch/x86/include/asm/bitops.h:311 >>>>> (discriminator 1) kernel/sched/core.c:2824 (discriminator 1)) >>>>> [ 788.568123] schedule_preempt_disabled (kernel/sched/core.c:2856) >>>>> [ 788.568123] mutex_lock_nested (kernel/locking/mutex.c:585 >>>>> kernel/locking/mutex.c:623) >>>>> [ 788.568123] kernfs_iop_permission (fs/kernfs/inode.c:366) >>>>> [ 788.568123] __inode_permission (fs/namei.c:374 fs/namei.c:408) >>>>> [ 788.568123] inode_permission (fs/namei.c:460) >>>>> [ 788.568123] link_path_walk (fs/namei.c:1520 fs/namei.c:1782) >>>>> [ 788.568123] path_init (fs/namei.c:1947) >>>>> [ 788.568123] path_lookupat (fs/namei.c:1989) >>>>> [ 788.568123] filename_lookup (fs/namei.c:2025) >>>>> [ 788.568123] user_path_at_empty (fs/namei.c:2189) >>>>> [ 788.568123] user_path_at (fs/namei.c:2200) >>>>> [ 788.568123] vfs_fstatat (fs/stat.c:106) >>>>> [ 788.568123] SYSC_newfstatat (fs/stat.c:298) >>>>> [ 788.568123] SyS_newfstatat (fs/stat.c:291) >>>>> [ 788.568123] tracesys_phase2 (arch/x86/kernel/entry_64.S:347) >>> OK, I guess it would help to update the WARN_ON()s while I am at it. :-/ >>> >>> Here is an updated patch that replaces the one resulting in the above >>> splat. >> >> That did the trick for me, but I don't think it made it to -next? > > Good to hear! May I add your Tested-by?
Sure. > And thank you for the reminder on -next, pushing it out now. Thanks! Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
