[openib-general] problem report: uninterruptible sleep in ib_uverbs

[Michael S. Tsirkin]

Hi!
With recent git code, an application that allocated a huge number of PDs got
blocked during cleanup.  Here's part of the sysrq dump:

gen2_basic    D ffff8100d9e9be58     0  4977   4846                     (NOTLB)
 ffff8100d9e9be58 ffff81011f0901e0 ffff81000000e400 ffff81000102fed8
 0000000000000002 000000020000000a ffff81011bf32730 ffff81011bf32908
 0000000000009372 000138bb2a26cb8a ffff81011c0dc0c0 0000000000000000
Call Trace:
 [<ffffffff80515e30>] __down_write_nested+0x82/0x9a
 [<ffffffff8802c236>] :ib_uverbs:idr_write_uobj+0x19/0x2e
 [<ffffffff8802cabb>] :ib_uverbs:ib_uverbs_dealloc_pd+0x41/0xd2
 [<ffffffff8802b98d>] :ib_uverbs:ib_uverbs_write+0xc4/0xd3
 [<000000000000000c>]

I didn't observe this before the locking changes in core.

-- 
MST