From a3e9af95f794d000debc2a5ba3186ba85a6e115f Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 1 May 2017 10:00:02 -0700 Subject: libnvdimm: restore "libnvdimm: band aid btt vs clear poison locking" This continues the 4.11 status quo of disabling of error clearing from the BTT I/O path. Toshi found that even though we have eliminated all the libnvdimm sources of sleeping-while-atomic triggers, we still have sleeping operations that will occur in the path to send the ACPI DSM to the DIMM to clear the error: BUG: sleeping function called from invalid context at mm/slab.h:432 in_atomic(): 1, irqs_disabled(): 0, pid: 13353, name: dd Call Trace: dump_stack+0x86/0xc3 ___might_sleep+0x17d/0x250 __might_sleep+0x4a/0x80 __kmalloc+0x1c0/0x2e0 acpi_os_allocate_zeroed+0x2d/0x2f acpi_evaluate_object+0x59/0x3b1 acpi_evaluate_dsm+0xbd/0x10c acpi_nfit_ctl+0x1ef/0x7c0 [nfit] ? nsio_rw_bytes+0x152/0x280 nvdimm_clear_poison+0x77/0x140 nsio_rw_bytes+0x18f/0x280 btt_write_pg+0x1d4/0x3d0 [nd_btt] btt_make_request+0x119/0x2d0 [nd_btt] A solution for tracking and handling media errors natively in the BTT is needed. Cc: Jeff Moyer Cc: Dave Jiang Cc: Vishal Verma Reported-by: Toshi Kani Signed-off-by: Dan Williams --- drivers/nvdimm/claim.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'drivers/nvdimm') diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c index 35b210dc1e56..6945e35058bf 100644 --- a/drivers/nvdimm/claim.c +++ b/drivers/nvdimm/claim.c @@ -250,7 +250,16 @@ 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 the ACPI DSM path for + * clearing the error takes sleeping locks and allocates + * memory. An explicit error clearing path, and support + * for tracking badblocks in BTT metadata is needed to + * work around this collision. + */ + if (IS_ALIGNED(offset, 512) && IS_ALIGNED(size, 512) + && (!ndns->claim || !is_nd_btt(ndns->claim))) { long cleared; cleared = nvdimm_clear_poison(&ndns->dev, -- cgit v1.2.3-59-g8ed1b