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Subject[PATCH 4.14 028/237] IB/hfi1: Close window for pq and request coliding
Date
From: Mike Marciniszyn <mike.marciniszyn@intel.com>

commit be8638344c70bf492963ace206a9896606b6922d upstream.

Cleaning up a pq can result in the following warning and panic:

WARNING: CPU: 52 PID: 77418 at lib/list_debug.c:53 __list_del_entry+0x63/0xd0
list_del corruption, ffff88cb2c6ac068->next is LIST_POISON1 (dead000000000100)
Modules linked in: mmfs26(OE) mmfslinux(OE) tracedev(OE) 8021q garp mrp ib_isert iscsi_target_mod target_core_mod crc_t10dif crct10dif_generic opa_vnic rpcrdma ib_iser libiscsi scsi_transport_iscsi ib_ipoib(OE) bridge stp llc iTCO_wdt iTCO_vendor_support intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm irqbypass crct10dif_pclmul crct10dif_common crc32_pclmul ghash_clmulni_intel ast aesni_intel ttm lrw gf128mul glue_helper ablk_helper drm_kms_helper cryptd syscopyarea sysfillrect sysimgblt fb_sys_fops drm pcspkr joydev lpc_ich mei_me drm_panel_orientation_quirks i2c_i801 mei wmi ipmi_si ipmi_devintf ipmi_msghandler nfit libnvdimm acpi_power_meter acpi_pad hfi1(OE) rdmavt(OE) rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm ib_core binfmt_misc numatools(OE) xpmem(OE) ip_tables
nfsv3 nfs_acl nfs lockd grace sunrpc fscache igb ahci i2c_algo_bit libahci dca ptp libata pps_core crc32c_intel [last unloaded: i2c_algo_bit]
CPU: 52 PID: 77418 Comm: pvbatch Kdump: loaded Tainted: G OE ------------ 3.10.0-957.38.3.el7.x86_64 #1
Hardware name: HPE.COM HPE SGI 8600-XA730i Gen10/X11DPT-SB-SG007, BIOS SBED1229 01/22/2019
Call Trace:
[<ffffffff90365ac0>] dump_stack+0x19/0x1b
[<ffffffff8fc98b78>] __warn+0xd8/0x100
[<ffffffff8fc98bff>] warn_slowpath_fmt+0x5f/0x80
[<ffffffff8ff970c3>] __list_del_entry+0x63/0xd0
[<ffffffff8ff9713d>] list_del+0xd/0x30
[<ffffffff8fddda70>] kmem_cache_destroy+0x50/0x110
[<ffffffffc0328130>] hfi1_user_sdma_free_queues+0xf0/0x200 [hfi1]
[<ffffffffc02e2350>] hfi1_file_close+0x70/0x1e0 [hfi1]
[<ffffffff8fe4519c>] __fput+0xec/0x260
[<ffffffff8fe453fe>] ____fput+0xe/0x10
[<ffffffff8fcbfd1b>] task_work_run+0xbb/0xe0
[<ffffffff8fc2bc65>] do_notify_resume+0xa5/0xc0
[<ffffffff90379134>] int_signal+0x12/0x17
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffff8fe1f93e>] kmem_cache_close+0x7e/0x300
PGD 2cdab19067 PUD 2f7bfdb067 PMD 0
Oops: 0000 [#1] SMP
Modules linked in: mmfs26(OE) mmfslinux(OE) tracedev(OE) 8021q garp mrp ib_isert iscsi_target_mod target_core_mod crc_t10dif crct10dif_generic opa_vnic rpcrdma ib_iser libiscsi scsi_transport_iscsi ib_ipoib(OE) bridge stp llc iTCO_wdt iTCO_vendor_support intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm irqbypass crct10dif_pclmul crct10dif_common crc32_pclmul ghash_clmulni_intel ast aesni_intel ttm lrw gf128mul glue_helper ablk_helper drm_kms_helper cryptd syscopyarea sysfillrect sysimgblt fb_sys_fops drm pcspkr joydev lpc_ich mei_me drm_panel_orientation_quirks i2c_i801 mei wmi ipmi_si ipmi_devintf ipmi_msghandler nfit libnvdimm acpi_power_meter acpi_pad hfi1(OE) rdmavt(OE) rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm ib_core binfmt_misc numatools(OE) xpmem(OE) ip_tables
nfsv3 nfs_acl nfs lockd grace sunrpc fscache igb ahci i2c_algo_bit libahci dca ptp libata pps_core crc32c_intel [last unloaded: i2c_algo_bit]
CPU: 52 PID: 77418 Comm: pvbatch Kdump: loaded Tainted: G W OE ------------ 3.10.0-957.38.3.el7.x86_64 #1
Hardware name: HPE.COM HPE SGI 8600-XA730i Gen10/X11DPT-SB-SG007, BIOS SBED1229 01/22/2019
task: ffff88cc26db9040 ti: ffff88b5393a8000 task.ti: ffff88b5393a8000
RIP: 0010:[<ffffffff8fe1f93e>] [<ffffffff8fe1f93e>] kmem_cache_close+0x7e/0x300
RSP: 0018:ffff88b5393abd60 EFLAGS: 00010287
RAX: 0000000000000000 RBX: ffff88cb2c6ac000 RCX: 0000000000000003
RDX: 0000000000000400 RSI: 0000000000000400 RDI: ffffffff9095b800
RBP: ffff88b5393abdb0 R08: ffffffff9095b808 R09: ffffffff8ff77c19
R10: ffff88b73ce1f160 R11: ffffddecddde9800 R12: ffff88cb2c6ac000
R13: 000000000000000c R14: ffff88cf3fdca780 R15: 0000000000000000
FS: 00002aaaaab52500(0000) GS:ffff88b73ce00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000002d27664000 CR4: 00000000007607e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
[<ffffffff8fe20d44>] __kmem_cache_shutdown+0x14/0x80
[<ffffffff8fddda78>] kmem_cache_destroy+0x58/0x110
[<ffffffffc0328130>] hfi1_user_sdma_free_queues+0xf0/0x200 [hfi1]
[<ffffffffc02e2350>] hfi1_file_close+0x70/0x1e0 [hfi1]
[<ffffffff8fe4519c>] __fput+0xec/0x260
[<ffffffff8fe453fe>] ____fput+0xe/0x10
[<ffffffff8fcbfd1b>] task_work_run+0xbb/0xe0
[<ffffffff8fc2bc65>] do_notify_resume+0xa5/0xc0
[<ffffffff90379134>] int_signal+0x12/0x17
Code: 00 00 ba 00 04 00 00 0f 4f c2 3d 00 04 00 00 89 45 bc 0f 84 e7 01 00 00 48 63 45 bc 49 8d 04 c4 48 89 45 b0 48 8b 80 c8 00 00 00 <48> 8b 78 10 48 89 45 c0 48 83 c0 10 48 89 45 d0 48 8b 17 48 39
RIP [<ffffffff8fe1f93e>] kmem_cache_close+0x7e/0x300
RSP <ffff88b5393abd60>
CR2: 0000000000000010

The panic is the result of slab entries being freed during the destruction
of the pq slab.

The code attempts to quiesce the pq, but looking for n_req == 0 doesn't
account for new requests.

Fix the issue by using SRCU to get a pq pointer and adjust the pq free
logic to NULL the fd pq pointer prior to the quiesce.

Fixes: e87473bc1b6c ("IB/hfi1: Only set fd pointer when base context is completely initialized")
Link: https://lore.kernel.org/r/20200210131033.87408.81174.stgit@awfm-01.aw.intel.com
Reviewed-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/hw/hfi1/file_ops.c | 52 ++++++++++++++++++------------
drivers/infiniband/hw/hfi1/hfi.h | 5 ++
drivers/infiniband/hw/hfi1/user_exp_rcv.c | 3 -
drivers/infiniband/hw/hfi1/user_sdma.c | 17 ++++++---
4 files changed, 48 insertions(+), 29 deletions(-)

--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -195,23 +195,24 @@ static int hfi1_file_open(struct inode *

fd = kzalloc(sizeof(*fd), GFP_KERNEL);

- if (fd) {
- fd->rec_cpu_num = -1; /* no cpu affinity by default */
- fd->mm = current->mm;
- mmgrab(fd->mm);
- fd->dd = dd;
- kobject_get(&fd->dd->kobj);
- fp->private_data = fd;
- } else {
- fp->private_data = NULL;
-
- if (atomic_dec_and_test(&dd->user_refcount))
- complete(&dd->user_comp);
-
- return -ENOMEM;
- }
-
+ if (!fd || init_srcu_struct(&fd->pq_srcu))
+ goto nomem;
+ spin_lock_init(&fd->pq_rcu_lock);
+ spin_lock_init(&fd->tid_lock);
+ spin_lock_init(&fd->invalid_lock);
+ fd->rec_cpu_num = -1; /* no cpu affinity by default */
+ fd->mm = current->mm;
+ mmgrab(fd->mm);
+ fd->dd = dd;
+ kobject_get(&fd->dd->kobj);
+ fp->private_data = fd;
return 0;
+nomem:
+ kfree(fd);
+ fp->private_data = NULL;
+ if (atomic_dec_and_test(&dd->user_refcount))
+ complete(&dd->user_comp);
+ return -ENOMEM;
}

static long hfi1_file_ioctl(struct file *fp, unsigned int cmd,
@@ -417,21 +418,30 @@ static long hfi1_file_ioctl(struct file
static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from)
{
struct hfi1_filedata *fd = kiocb->ki_filp->private_data;
- struct hfi1_user_sdma_pkt_q *pq = fd->pq;
+ struct hfi1_user_sdma_pkt_q *pq;
struct hfi1_user_sdma_comp_q *cq = fd->cq;
int done = 0, reqs = 0;
unsigned long dim = from->nr_segs;
+ int idx;

- if (!cq || !pq)
+ idx = srcu_read_lock(&fd->pq_srcu);
+ pq = srcu_dereference(fd->pq, &fd->pq_srcu);
+ if (!cq || !pq) {
+ srcu_read_unlock(&fd->pq_srcu, idx);
return -EIO;
+ }

- if (!iter_is_iovec(from) || !dim)
+ if (!iter_is_iovec(from) || !dim) {
+ srcu_read_unlock(&fd->pq_srcu, idx);
return -EINVAL;
+ }

trace_hfi1_sdma_request(fd->dd, fd->uctxt->ctxt, fd->subctxt, dim);

- if (atomic_read(&pq->n_reqs) == pq->n_max_reqs)
+ if (atomic_read(&pq->n_reqs) == pq->n_max_reqs) {
+ srcu_read_unlock(&fd->pq_srcu, idx);
return -ENOSPC;
+ }

while (dim) {
int ret;
@@ -449,6 +459,7 @@ static ssize_t hfi1_write_iter(struct ki
reqs++;
}

+ srcu_read_unlock(&fd->pq_srcu, idx);
return reqs;
}

@@ -824,6 +835,7 @@ done:
if (atomic_dec_and_test(&dd->user_refcount))
complete(&dd->user_comp);

+ cleanup_srcu_struct(&fdata->pq_srcu);
kfree(fdata);
return 0;
}
--- a/drivers/infiniband/hw/hfi1/hfi.h
+++ b/drivers/infiniband/hw/hfi1/hfi.h
@@ -1353,10 +1353,13 @@ struct mmu_rb_handler;

/* Private data for file operations */
struct hfi1_filedata {
+ struct srcu_struct pq_srcu;
struct hfi1_devdata *dd;
struct hfi1_ctxtdata *uctxt;
struct hfi1_user_sdma_comp_q *cq;
- struct hfi1_user_sdma_pkt_q *pq;
+ /* update side lock for SRCU */
+ spinlock_t pq_rcu_lock;
+ struct hfi1_user_sdma_pkt_q __rcu *pq;
u16 subctxt;
/* for cpu affinity; -1 if none */
int rec_cpu_num;
--- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -90,9 +90,6 @@ int hfi1_user_exp_rcv_init(struct hfi1_f
struct hfi1_devdata *dd = uctxt->dd;
int ret = 0;

- spin_lock_init(&fd->tid_lock);
- spin_lock_init(&fd->invalid_lock);
-
fd->entry_to_rb = kcalloc(uctxt->expected_count,
sizeof(struct rb_node *),
GFP_KERNEL);
--- a/drivers/infiniband/hw/hfi1/user_sdma.c
+++ b/drivers/infiniband/hw/hfi1/user_sdma.c
@@ -179,7 +179,6 @@ int hfi1_user_sdma_alloc_queues(struct h
pq = kzalloc(sizeof(*pq), GFP_KERNEL);
if (!pq)
return -ENOMEM;
-
pq->dd = dd;
pq->ctxt = uctxt->ctxt;
pq->subctxt = fd->subctxt;
@@ -236,7 +235,7 @@ int hfi1_user_sdma_alloc_queues(struct h
goto pq_mmu_fail;
}

- fd->pq = pq;
+ rcu_assign_pointer(fd->pq, pq);
fd->cq = cq;

return 0;
@@ -264,8 +263,14 @@ int hfi1_user_sdma_free_queues(struct hf

trace_hfi1_sdma_user_free_queues(uctxt->dd, uctxt->ctxt, fd->subctxt);

- pq = fd->pq;
+ spin_lock(&fd->pq_rcu_lock);
+ pq = srcu_dereference_check(fd->pq, &fd->pq_srcu,
+ lockdep_is_held(&fd->pq_rcu_lock));
if (pq) {
+ rcu_assign_pointer(fd->pq, NULL);
+ spin_unlock(&fd->pq_rcu_lock);
+ synchronize_srcu(&fd->pq_srcu);
+ /* at this point there can be no more new requests */
if (pq->handler)
hfi1_mmu_rb_unregister(pq->handler);
iowait_sdma_drain(&pq->busy);
@@ -277,7 +282,8 @@ int hfi1_user_sdma_free_queues(struct hf
kfree(pq->req_in_use);
kmem_cache_destroy(pq->txreq_cache);
kfree(pq);
- fd->pq = NULL;
+ } else {
+ spin_unlock(&fd->pq_rcu_lock);
}
if (fd->cq) {
vfree(fd->cq->comps);
@@ -321,7 +327,8 @@ int hfi1_user_sdma_process_request(struc
{
int ret = 0, i;
struct hfi1_ctxtdata *uctxt = fd->uctxt;
- struct hfi1_user_sdma_pkt_q *pq = fd->pq;
+ struct hfi1_user_sdma_pkt_q *pq =
+ srcu_dereference(fd->pq, &fd->pq_srcu);
struct hfi1_user_sdma_comp_q *cq = fd->cq;
struct hfi1_devdata *dd = pq->dd;
unsigned long idx = 0;

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