12:05 p.m.
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(a)intel.com>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
---
drivers/acpi/nfit/core.c | 15 +++------------
1 file 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,