Tomas Glozar wrote:
> čt 14. 9. 2023 v 22:18 odesílatel Ira Weiny <ira.we...@intel.com> napsal:
> > Is the bug in 1 of 2 places?
> >
> > 1) When btt_write_pg()->lock_map() (when the number of lanes is < number
> > of cpus) and the lane is acquired is called?
> >
> > *or*
> >
> > 2) When nd_region_acquire_lane() internally trys to take it's lock?
> >
> > A copy/paste of the BUG observed would have been more clear I think.
> >
>
> The BUG was observed on btt_write_pg()->lock_map(), but I assume the
> BUG will also happen on the lock in nd_region_acquire_lane, since that
> is also a spin lock, i.e. a sleeping lock on RT.
>
> BUG observed in dmesg when running ndctl tests on RT kernel without the patch:
Thanks for clarifying. Could you respin the patch with the text below?
That would have saved me a lot of time digging to see what the code path
was.
...
BUG: sleeping function called from invalid context at
kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4903, name:
libndctl
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
1 lock held by libndctl/4903:
#0: ffff8c184a270060 (&arena->map_locks[i].lock){+.+.}-{2:2}, at:
btt_write_pg+0x2d7/0x500 [nd_btt]
Preemption disabled at:
[<ffffffffc1313db5>] nd_region_acquire_lane+0x15/0x90 [libnvdimm]
Call Trace:
<TASK>
dump_stack_lvl+0x8e/0xb0
__might_resched+0x19b/0x250
rt_spin_lock+0x4c/0x100
? btt_write_pg+0x2d7/0x500 [nd_btt]
btt_write_pg+0x2d7/0x500 [nd_btt]
? local_clock_noinstr+0x9/0xc0
btt_submit_bio+0x16d/0x270 [nd_btt]
__submit_bio+0x48/0x80
__submit_bio_noacct+0x7e/0x1e0
submit_bio_wait+0x58/0xb0
__blkdev_direct_IO_simple+0x107/0x240
? inode_set_ctime_current+0x51/0x110
? __pfx_submit_bio_wait_endio+0x10/0x10
blkdev_write_iter+0x1d8/0x290
vfs_write+0x237/0x330
...
With a respin including this trace:
Reviewed-by: Ira Weiny <ira.we...@intel.com>
