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authorDan Williams <dan.j.williams@intel.com>2018-11-03 17:53:09 -0700
committerDan Williams <dan.j.williams@intel.com>2018-11-10 09:54:28 -0800
commit2121db09630113e67b51ae78c18115f1858f648a (patch)
tree4b397bbf46cc95ad8a7d4a76ec28bb298110d015
parent3fa58dcab50a0aa16817f16a8d38aee869eb3fb9 (diff)
Revert "acpi, nfit: Further restrict userspace ARS start requests"
The following lockdep splat results from acquiring the init_mutex in acpi_nfit_clear_to_send(): WARNING: possible circular locking dependency detected lt-daxdev-error/7216 is trying to acquire lock: 00000000f694db15 (&acpi_desc->init_mutex){+.+.}, at: acpi_nfit_clear_to_send+0x27/0x80 [nfit] but task is already holding lock: 00000000182298f2 (&nvdimm_bus->reconfig_mutex){+.+.}, at: __nd_ioctl+0x457/0x610 [libnvdimm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&nvdimm_bus->reconfig_mutex){+.+.}: nvdimm_badblocks_populate+0x41/0x150 [libnvdimm] nd_region_notify+0x95/0xb0 [libnvdimm] nd_device_notify+0x40/0x50 [libnvdimm] ars_complete+0x7f/0xd0 [nfit] acpi_nfit_scrub+0xbb/0x410 [nfit] process_one_work+0x22b/0x5c0 worker_thread+0x3c/0x390 kthread+0x11e/0x140 ret_from_fork+0x3a/0x50 -> #0 (&acpi_desc->init_mutex){+.+.}: __mutex_lock+0x83/0x980 acpi_nfit_clear_to_send+0x27/0x80 [nfit] __nd_ioctl+0x474/0x610 [libnvdimm] nd_ioctl+0xa4/0xb0 [libnvdimm] do_vfs_ioctl+0xa5/0x6e0 ksys_ioctl+0x70/0x80 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x60/0x210 entry_SYSCALL_64_after_hwframe+0x49/0xbe New infrastructure is needed to be able to perform this check without acquiring the lock. Fixes: 594861215c83 ("acpi, nfit: Further restrict userspace ARS start") Cc: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
-rw-r--r--drivers/acpi/nfit/core.c15
1 files changed, 3 insertions, 12 deletions
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 5970b8f5f768..14d9f5bea015 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -3341,8 +3341,6 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
struct nvdimm *nvdimm, unsigned int cmd)
{
struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
- struct nfit_spa *nfit_spa;
- int rc = 0;
if (nvdimm)
return 0;
@@ -3355,17 +3353,10 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
* just needs guarantees that any ARS it initiates are not
* interrupted by any intervening start requests from userspace.
*/
- mutex_lock(&acpi_desc->init_mutex);
- list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
- if (acpi_desc->scrub_spa
- || test_bit(ARS_REQ_SHORT, &nfit_spa->ars_state)
- || test_bit(ARS_REQ_LONG, &nfit_spa->ars_state)) {
- rc = -EBUSY;
- break;
- }
- mutex_unlock(&acpi_desc->init_mutex);
+ if (work_busy(&acpi_desc->dwork.work))
+ return -EBUSY;
- return rc;
+ return 0;
}
int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc,