From 4aa5615e080a9855e607accc75b07ab79b252dde Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 7 Apr 2017 12:25:52 -0700 Subject: [PATCH] libnvdimm: band aid btt vs clear poison locking The following warning results from holding a lane spinlock, preempt_disable(), or the btt map spinlock and then trying to take the reconfig_mutex to walk the poison list and potentially add new entries. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747 in_atomic(): 1, irqs_disabled(): 0, pid: 17159, name: dd [..] Call Trace: dump_stack+0x85/0xc8 ___might_sleep+0x184/0x250 __might_sleep+0x4a/0x90 __mutex_lock+0x58/0x9b0 ? nvdimm_bus_lock+0x21/0x30 [libnvdimm] ? __nvdimm_bus_badblocks_clear+0x2f/0x60 [libnvdimm] ? acpi_nfit_forget_poison+0x79/0x80 [nfit] ? _raw_spin_unlock+0x27/0x40 mutex_lock_nested+0x1b/0x20 nvdimm_bus_lock+0x21/0x30 [libnvdimm] nvdimm_forget_poison+0x25/0x50 [libnvdimm] nvdimm_clear_poison+0x106/0x140 [libnvdimm] nsio_rw_bytes+0x164/0x270 [libnvdimm] btt_write_pg+0x1de/0x3e0 [nd_btt] ? blk_queue_enter+0x30/0x290 btt_make_request+0x11a/0x310 [nd_btt] ? blk_queue_enter+0xb7/0x290 ? blk_queue_enter+0x30/0x290 generic_make_request+0x118/0x3b0 As a minimal fix, disable error clearing when the BTT is enabled for the namespace. For the final fix a larger rework of the poison list locking is needed. Note that this is not a problem in the blk case since that path never calls nvdimm_clear_poison(). Cc: Fixes: 82bf1037f2ca ("libnvdimm: check and clear poison before writing to pmem") Cc: Dave Jiang [jeff: dynamically disable error clearing in the btt case] Suggested-by: Jeff Moyer Reviewed-by: Jeff Moyer Reported-by: Vishal Verma Signed-off-by: Dan Williams --- drivers/nvdimm/claim.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c index b3323c0697f6..ca6d572c48fc 100644 --- a/drivers/nvdimm/claim.c +++ b/drivers/nvdimm/claim.c @@ -243,7 +243,15 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns, } if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) { - if (IS_ALIGNED(offset, 512) && IS_ALIGNED(size, 512)) { + /* + * FIXME: nsio_rw_bytes() may be called from atomic + * context in the btt case and nvdimm_clear_poison() + * takes a sleeping lock. Until the locking can be + * reworked this capability requires that the namespace + * is not claimed by btt. + */ + if (IS_ALIGNED(offset, 512) && IS_ALIGNED(size, 512) + && (!ndns->claim || !is_nd_btt(ndns->claim))) { long cleared; cleared = nvdimm_clear_poison(&ndns->dev, offset, size); -- 2.30.2