From: Devesh Sharma <[email protected]>
If the rdma_create_qp fails to create qp due to device firmware being in invalid state
xprtrdma still tries to destroy the non-existant qp and ends up in a NULL pointer reference
crash.
Adding proper checks for vaidating QP pointer avoids this to happen.
Signed-off-by: Devesh Sharma <[email protected]>
---
net/sunrpc/xprtrdma/verbs.c | 34 ++++++++++++++++++++++++++++------
1 files changed, 28 insertions(+), 6 deletions(-)
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 9372656..c01d91e 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -620,7 +620,7 @@ rpcrdma_ia_close(struct rpcrdma_ia *ia)
__func__, rc);
}
if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) {
- if (ia->ri_id->qp)
+ if (!IS_ERR(ia->ri_id->qp))
rdma_destroy_qp(ia->ri_id);
rdma_destroy_id(ia->ri_id);
ia->ri_id = NULL;
@@ -794,7 +794,7 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
dprintk("RPC: %s: entering, connected is %d\n",
__func__, ep->rep_connected);
- if (ia->ri_id->qp) {
+ if (!IS_ERR(ia->ri_id->qp)) {
rc = rpcrdma_ep_disconnect(ep, ia);
if (rc)
dprintk("RPC: %s: rpcrdma_ep_disconnect"
@@ -831,10 +831,12 @@ rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
if (ep->rep_connected != 0) {
struct rpcrdma_xprt *xprt;
retry:
- rc = rpcrdma_ep_disconnect(ep, ia);
- if (rc && rc != -ENOTCONN)
- dprintk("RPC: %s: rpcrdma_ep_disconnect"
+ if (!IS_ERR(ia->ri_id->qp)) {
+ rc = rpcrdma_ep_disconnect(ep, ia);
+ if (rc && rc != -ENOTCONN)
+ dprintk("RPC: %s: rpcrdma_ep_disconnect"
" status %i\n", __func__, rc);
+ }
rpcrdma_clean_cq(ep->rep_cq);
xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
@@ -859,7 +861,9 @@ retry:
goto out;
}
/* END TEMP */
- rdma_destroy_qp(ia->ri_id);
+ if (!IS_ERR(ia->ri_id->qp)) {
+ rdma_destroy_qp(ia->ri_id);
+ }
rdma_destroy_id(ia->ri_id);
ia->ri_id = id;
}
@@ -1557,6 +1561,13 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,
frmr_wr.wr.fast_reg.rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
DECR_CQCOUNT(&r_xprt->rx_ep);
+ if (IS_ERR(ia->ri_is->qp)) {
+ rc = PTR_ERR(ia->ri_is->qp);
+ while (i--)
+ rpcrdma_unmap_one(ia, --seg);
+ goto out;
+ }
+
rc = ib_post_send(ia->ri_id->qp, post_wr, &bad_wr);
if (rc) {
@@ -1571,6 +1582,7 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,
seg1->mr_len = len;
}
*nsegs = i;
+out:
return rc;
}
@@ -1592,6 +1604,10 @@ rpcrdma_deregister_frmr_external(struct rpcrdma_mr_seg *seg,
invalidate_wr.ex.invalidate_rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
DECR_CQCOUNT(&r_xprt->rx_ep);
+ if (IS_ERR(ia->ri_id->qp)) {
+ return PTR_ERR(ia->ri_id->qp);
+ }
+
rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
if (rc)
dprintk("RPC: %s: failed ib_post_send for invalidate,"
@@ -1923,6 +1939,9 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia,
send_wr.send_flags = IB_SEND_SIGNALED;
}
+ if (IS_ERR(ia->ri_id->qp))
+ return PTR_ERR(ia->ri_id->qp);
+
rc = ib_post_send(ia->ri_id->qp, &send_wr, &send_wr_fail);
if (rc)
dprintk("RPC: %s: ib_post_send returned %i\n", __func__,
@@ -1951,6 +1970,9 @@ rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
rep->rr_iov.addr, rep->rr_iov.length, DMA_BIDIRECTIONAL);
DECR_CQCOUNT(ep);
+
+ if (IS_ERR(ia->ri_id->qp))
+ return PTR_ERR(ia->ri_id->qp);
rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);
if (rc)
--
1.7.1
This is the stack trace seen during one of the test cases where rdma_create_qp() made to fail deliberately and nfs-rdma client ended up in Panic.
<3>ocrdma_mbx_create_qp(0) rq_err
<3>ocrdma_mbx_create_qp(0) sq_err
<3>ocrdma_create_qp(0) error=-22
<1>BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
<1>IP: [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core]
<4>PGD 46427d067 PUD 456244067 PMD 0
<4>Oops: 0000 [#1] SMP
<4>last sysfs file: /sys/kernel/mm/ksm/run
<4>CPU 8
<4>Modules linked in: nfs lockd fscache auth_rpcgss nfs_acl xprtrdma(U) ocrdma(U) be2net(U) ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables bridge stp llc autofs4 des_generic ecb md4 nls_utf8 cifs sunrpc rdma_ucm(U) rdma_cm(U) iw_cm(U) ib_addr(U) ib_ipoib(U) ib_cm(U) ib_sa(U) ipv6 ib_uverbs(U) ib_umad(U) iw_nes(U) libcrc32c iw_cxgb4(U) cxgb4(U) iw_cxgb3(U) cxgb3(U) mdio ib_qib(U) mlx4_en(U) mlx4_ib(U) mlx4_core(U) ib_mthca(U) ib_mad(U) ib_core(U) compat(U) vhost_net macvtap macvlan tun kvm uinput power_meter sg microcode i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support igb ptp pps_core ioatdma dca i7core_edac edac_core ext3 jbd mbcache sr_mod cdrom sd_mod crc_t10dif usb_storage pata_acpi ata_generic ata_piix mptsas mptscsih mptbase scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod [last unloaded: be2net]
<4>
<4>Pid: 1697, comm: events/8 Not tainted 2.6.32-358.el6.x86_64 #1 Cisco Systems Inc R210-2121605W/R210-2121605W
<4>RIP: 0010:[<ffffffffa0265451>] [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core]
<4>RSP: 0018:ffff880467731cb0 EFLAGS: 00010282
<4>RAX: ffff880467730000 RBX: ffff88046811e000 RCX: ffff88046313a040
<4>RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
<4>RBP: ffff880467731ce0 R08: ffff880467731c78 R09: 0000000000000000
<4>R10: 0000000000000000 R11: 0000000000000000 R12: ffff88046811e210
<4>R13: 0000000000000000 R14: ffff880466696400 R15: ffffe8ffffb01d08
<4>FS: 0000000000000000(0000) GS:ffff880036900000(0000) knlGS:0000000000000000
<4>CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
<4>CR2: 0000000000000040 CR3: 00000004624b8000 CR4: 00000000000007e0
<4>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
<4>Process events/8 (pid: 1697, threadinfo ffff880467730000, task ffff88046313a040)
<4>Stack:
<4> ffff8804679cd5b8 ffff88046811e000 ffff88046811e210 0000000000000000
<4><d> ffff880466696400 ffffe8ffffb01d08 ffff880467731d00 ffffffffa0588f51
<4><d> ffff8804679cd5e0 ffff8804679cd598 ffff880467731e10 ffffffffa02e9e75
<4>Call Trace:
<4> [<ffffffffa0588f51>] rdma_destroy_qp+0x31/0x50 [rdma_cm]
<4> [<ffffffffa02e9e75>] rpcrdma_ep_connect+0x135/0x3e0 [xprtrdma]
<4> [<ffffffff8150d6e0>] ? thread_return+0x4e/0x76e
<4> [<ffffffffa05d06ae>] ? rpc_wake_up_task_queue_locked+0x18e/0x270 [sunrpc]
<4> [<ffffffffa02e6ff0>] ? xprt_rdma_connect_worker+0x0/0xc0 [xprtrdma]
<4> [<ffffffffa02e7032>] xprt_rdma_connect_worker+0x42/0xc0 [xprtrdma]
<4> [<ffffffff81090ac0>] worker_thread+0x170/0x2a0
<4> [<ffffffff81096c80>] ? autoremove_wake_function+0x0/0x40
<4> [<ffffffff81090950>] ? worker_thread+0x0/0x2a0
<4> [<ffffffff81096916>] kthread+0x96/0xa0
<4> [<ffffffff8100c0ca>] child_rip+0xa/0x20
<4> [<ffffffff81096880>] ? kthread+0x0/0xa0
<4> [<ffffffff8100c0c0>] ? child_rip+0x0/0x20
<4>Code: 65 f0 4c 8b 6d f8 c9 c3 66 90 55 48 89 e5 48 83 ec 30 48 89 5d d8 4c 89 65 e0 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 0f 1f 44 00 00 <8b> 57 40 b8 f0 ff ff ff 49 89 fe 85 d2 75 39 4c 8b 67 58 49 39
<1>RIP [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core]
<4> RSP <ffff880467731cb0>
<4>CR2: 0000000000000040
-----Original Message-----
From: Trond Myklebust [mailto:[email protected]]
Sent: Tuesday, April 08, 2014 5:31 AM
To: Devesh Sharma
Cc: [email protected]; [email protected]
Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
On Apr 7, 2014, at 19:45, Devesh Sharma <[email protected]> wrote:
> Hi
> Inline Below:
>
> -----Original Message-----
> From: Trond Myklebust [mailto:[email protected]]
> Sent: Tuesday, April 08, 2014 4:58 AM
> To: Devesh Sharma
> Cc: [email protected]; [email protected]
> Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
>
>
> On Apr 7, 2014, at 18:30, [email protected] wrote:
>
>> From: Devesh Sharma <[email protected]>
>>
>> If the rdma_create_qp fails to create qp due to device firmware being
>> in invalid state xprtrdma still tries to destroy the non-existant qp
>> and ends up in a NULL pointer reference crash.
>> Adding proper checks for vaidating QP pointer avoids this to happen.
>>
>
> As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing?
> [DS]: If you focus on rpcrdma_ep_connect() function and assume that rdma_create_qp() has failed with some valid error code, then this callback function will return ep->rep_connected = some non-zero.
> Eventually xprt_rdma_connect_worker() will call rpcrdma_ep_connect()
> again and rpcrdma_ep_connect will try to free-up all the resources, now rdma_destroy_qp() will be called with invalid QP (which is NULL) pointer And hence kernel will panic. Please correct me if I am worng.
>
AFAICS your patch does nothing to address that problem. Instead it adds tests for IS_ERR(ia->ri_id->qp), which can never happen because ia->ri_id->qp is either NULL or points to a valid structure.
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData [email protected]
On Apr 7, 2014, at 19:45, Devesh Sharma <[email protected]> wrote:
> Hi
> Inline Below:
>
> -----Original Message-----
> From: Trond Myklebust [mailto:[email protected]]
> Sent: Tuesday, April 08, 2014 4:58 AM
> To: Devesh Sharma
> Cc: [email protected]; [email protected]
> Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
>
>
> On Apr 7, 2014, at 18:30, [email protected] wrote:
>
>> From: Devesh Sharma <[email protected]>
>>
>> If the rdma_create_qp fails to create qp due to device firmware being
>> in invalid state xprtrdma still tries to destroy the non-existant qp
>> and ends up in a NULL pointer reference crash.
>> Adding proper checks for vaidating QP pointer avoids this to happen.
>>
>
> As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing?
> [DS]: If you focus on rpcrdma_ep_connect() function and assume that rdma_create_qp() has failed with some valid error code, then this callback function will return ep->rep_connected = some non-zero.
> Eventually xprt_rdma_connect_worker() will call rpcrdma_ep_connect() again and rpcrdma_ep_connect will try to free-up all the resources, now rdma_destroy_qp() will be called with invalid QP (which is NULL) pointer
> And hence kernel will panic. Please correct me if I am worng.
>
AFAICS your patch does nothing to address that problem. Instead it adds tests for IS_ERR(ia->ri_id->qp), which can never happen because ia->ri_id->qp is either NULL or points to a valid structure.
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData
[email protected]
Yes, This is correct, I should check for a NULL pointer instead of IS_ERR(). I will send a V1 for this.
-----Original Message-----
From: Trond Myklebust [mailto:[email protected]]
Sent: Tuesday, April 08, 2014 5:43 AM
To: Devesh Sharma
Cc: [email protected]; [email protected]
Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
On Apr 7, 2014, at 20:07, Devesh Sharma <[email protected]> wrote:
> This is the stack trace seen during one of the test cases where rdma_create_qp() made to fail deliberately and nfs-rdma client ended up in Panic.
>
> <3>ocrdma_mbx_create_qp(0) rq_err
> <3>ocrdma_mbx_create_qp(0) sq_err
> <3>ocrdma_create_qp(0) error=-22
> <1>BUG: unable to handle kernel NULL pointer dereference at
> 0000000000000040
> <1>IP: [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core] <4>PGD
> 46427d067 PUD 456244067 PMD 0
> <4>Oops: 0000 [#1] SMP
> <4>last sysfs file: /sys/kernel/mm/ksm/run <4>CPU 8 <4>Modules linked
> in: nfs lockd fscache auth_rpcgss nfs_acl xprtrdma(U) ocrdma(U)
> be2net(U) ip6table_filter ip6_tables ebtable_nat ebtables
> ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4
> xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle
> iptable_filter ip_tables bridge stp llc autofs4 des_generic ecb md4
> nls_utf8 cifs sunrpc rdma_ucm(U) rdma_cm(U) iw_cm(U) ib_addr(U)
> ib_ipoib(U) ib_cm(U) ib_sa(U) ipv6 ib_uverbs(U) ib_umad(U) iw_nes(U)
> libcrc32c iw_cxgb4(U) cxgb4(U) iw_cxgb3(U) cxgb3(U) mdio ib_qib(U)
> mlx4_en(U) mlx4_ib(U) mlx4_core(U) ib_mthca(U) ib_mad(U) ib_core(U)
> compat(U) vhost_net macvtap macvlan tun kvm uinput power_meter sg
> microcode i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support igb ptp
> pps_core ioatdma dca i7core_edac edac_core ext3 jbd mbcache sr_mod
> cdrom sd_mod crc_t10dif usb_storage pata_acpi ata_generic ata_piix
> mptsas mptscsih mptbase scsi_transport_sas dm_mirror dm_region_hash
> dm_log dm_mod [last unloaded: be2net] <4>
> <4>Pid: 1697, comm: events/8 Not tainted 2.6.32-358.el6.x86_64 #1
> Cisco Systems Inc R210-2121605W/R210-2121605W
> <4>RIP: 0010:[<ffffffffa0265451>] [<ffffffffa0265451>]
> ib_destroy_qp+0x21/0x120 [ib_core]
Sure, but that is a NULL pointer dereference. Why are you adding these tests for IS_ERR(), which won't catch NULL pointers, and are instead testing for conditions that can never happen?
> <4>RSP: 0018:ffff880467731cb0 EFLAGS: 00010282
> <4>RAX: ffff880467730000 RBX: ffff88046811e000 RCX: ffff88046313a040
> <4>RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> <4>RBP: ffff880467731ce0 R08: ffff880467731c78 R09: 0000000000000000
> <4>R10: 0000000000000000 R11: 0000000000000000 R12: ffff88046811e210
> <4>R13: 0000000000000000 R14: ffff880466696400 R15: ffffe8ffffb01d08
> <4>FS: 0000000000000000(0000) GS:ffff880036900000(0000)
> knlGS:0000000000000000
> <4>CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> <4>CR2: 0000000000000040 CR3: 00000004624b8000 CR4: 00000000000007e0
> <4>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> <4>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> <4>Process events/8 (pid: 1697, threadinfo ffff880467730000, task
> ffff88046313a040)
> <4>Stack:
> <4> ffff8804679cd5b8 ffff88046811e000 ffff88046811e210
> 0000000000000000 <4><d> ffff880466696400 ffffe8ffffb01d08
> ffff880467731d00 ffffffffa0588f51 <4><d> ffff8804679cd5e0
> ffff8804679cd598 ffff880467731e10 ffffffffa02e9e75 <4>Call Trace:
> <4> [<ffffffffa0588f51>] rdma_destroy_qp+0x31/0x50 [rdma_cm] <4>
> [<ffffffffa02e9e75>] rpcrdma_ep_connect+0x135/0x3e0 [xprtrdma] <4>
> [<ffffffff8150d6e0>] ? thread_return+0x4e/0x76e <4>
> [<ffffffffa05d06ae>] ? rpc_wake_up_task_queue_locked+0x18e/0x270
> [sunrpc] <4> [<ffffffffa02e6ff0>] ? xprt_rdma_connect_worker+0x0/0xc0
> [xprtrdma] <4> [<ffffffffa02e7032>] xprt_rdma_connect_worker+0x42/0xc0
> [xprtrdma] <4> [<ffffffff81090ac0>] worker_thread+0x170/0x2a0 <4>
> [<ffffffff81096c80>] ? autoremove_wake_function+0x0/0x40 <4>
> [<ffffffff81090950>] ? worker_thread+0x0/0x2a0 <4>
> [<ffffffff81096916>] kthread+0x96/0xa0 <4> [<ffffffff8100c0ca>]
> child_rip+0xa/0x20 <4> [<ffffffff81096880>] ? kthread+0x0/0xa0 <4>
> [<ffffffff8100c0c0>] ? child_rip+0x0/0x20
> <4>Code: 65 f0 4c 8b 6d f8 c9 c3 66 90 55 48 89 e5 48 83 ec 30 48 89
> 5d d8 4c 89 65 e0 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 0f 1f 44 00 00
> <8b> 57 40 b8 f0 ff ff ff 49 89 fe 85 d2 75 39 4c 8b 67 58 49 39
> <1>RIP [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core] <4>
> RSP <ffff880467731cb0>
> <4>CR2: 0000000000000040
>
> -----Original Message-----
> From: Trond Myklebust [mailto:[email protected]]
> Sent: Tuesday, April 08, 2014 5:31 AM
> To: Devesh Sharma
> Cc: [email protected]; [email protected]
> Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
>
>
> On Apr 7, 2014, at 19:45, Devesh Sharma <[email protected]> wrote:
>
>> Hi
>> Inline Below:
>>
>> -----Original Message-----
>> From: Trond Myklebust [mailto:[email protected]]
>> Sent: Tuesday, April 08, 2014 4:58 AM
>> To: Devesh Sharma
>> Cc: [email protected]; [email protected]
>> Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
>>
>>
>> On Apr 7, 2014, at 18:30, [email protected] wrote:
>>
>>> From: Devesh Sharma <[email protected]>
>>>
>>> If the rdma_create_qp fails to create qp due to device firmware
>>> being in invalid state xprtrdma still tries to destroy the
>>> non-existant qp and ends up in a NULL pointer reference crash.
>>> Adding proper checks for vaidating QP pointer avoids this to happen.
>>>
>>
>> As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing?
>> [DS]: If you focus on rpcrdma_ep_connect() function and assume that rdma_create_qp() has failed with some valid error code, then this callback function will return ep->rep_connected = some non-zero.
>> Eventually xprt_rdma_connect_worker() will call rpcrdma_ep_connect()
>> again and rpcrdma_ep_connect will try to free-up all the resources, now rdma_destroy_qp() will be called with invalid QP (which is NULL) pointer And hence kernel will panic. Please correct me if I am worng.
>>
>
> AFAICS your patch does nothing to address that problem. Instead it adds tests for IS_ERR(ia->ri_id->qp), which can never happen because ia->ri_id->qp is either NULL or points to a valid structure.
>
> _________________________________
> Trond Myklebust
> Linux NFS client maintainer, PrimaryData
> [email protected]
>
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData [email protected]
Hi
Inline Below:
-----Original Message-----
From: Trond Myklebust [mailto:[email protected]]
Sent: Tuesday, April 08, 2014 4:58 AM
To: Devesh Sharma
Cc: [email protected]; [email protected]
Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
On Apr 7, 2014, at 18:30, [email protected] wrote:
> From: Devesh Sharma <[email protected]>
>
> If the rdma_create_qp fails to create qp due to device firmware being
> in invalid state xprtrdma still tries to destroy the non-existant qp
> and ends up in a NULL pointer reference crash.
> Adding proper checks for vaidating QP pointer avoids this to happen.
>
As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing?
[DS]: If you focus on rpcrdma_ep_connect() function and assume that rdma_create_qp() has failed with some valid error code, then this callback function will return ep->rep_connected = some non-zero.
Eventually xprt_rdma_connect_worker() will call rpcrdma_ep_connect() again and rpcrdma_ep_connect will try to free-up all the resources, now rdma_destroy_qp() will be called with invalid QP (which is NULL) pointer
And hence kernel will panic. Please correct me if I am worng.
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData [email protected]
On Apr 7, 2014, at 20:07, Devesh Sharma <[email protected]> wrote:
> This is the stack trace seen during one of the test cases where rdma_create_qp() made to fail deliberately and nfs-rdma client ended up in Panic.
>
> <3>ocrdma_mbx_create_qp(0) rq_err
> <3>ocrdma_mbx_create_qp(0) sq_err
> <3>ocrdma_create_qp(0) error=-22
> <1>BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
> <1>IP: [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core]
> <4>PGD 46427d067 PUD 456244067 PMD 0
> <4>Oops: 0000 [#1] SMP
> <4>last sysfs file: /sys/kernel/mm/ksm/run
> <4>CPU 8
> <4>Modules linked in: nfs lockd fscache auth_rpcgss nfs_acl xprtrdma(U) ocrdma(U) be2net(U) ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables bridge stp llc autofs4 des_generic ecb md4 nls_utf8 cifs sunrpc rdma_ucm(U) rdma_cm(U) iw_cm(U) ib_addr(U) ib_ipoib(U) ib_cm(U) ib_sa(U) ipv6 ib_uverbs(U) ib_umad(U) iw_nes(U) libcrc32c iw_cxgb4(U) cxgb4(U) iw_cxgb3(U) cxgb3(U) mdio ib_qib(U) mlx4_en(U) mlx4_ib(U) mlx4_core(U) ib_mthca(U) ib_mad(U) ib_core(U) compat(U) vhost_net macvtap macvlan tun kvm uinput power_meter sg microcode i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support igb ptp pps_core ioatdma dca i7core_edac edac_core ext3 jbd mbcache sr_mod cdrom sd_mod crc_t10dif usb_storage pata_acpi ata_generic ata_piix mptsas mptscsih mptbase scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod [last unloaded: be2net]
> <4>
> <4>Pid: 1697, comm: events/8 Not tainted 2.6.32-358.el6.x86_64 #1 Cisco Systems Inc R210-2121605W/R210-2121605W
> <4>RIP: 0010:[<ffffffffa0265451>] [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core]
Sure, but that is a NULL pointer dereference. Why are you adding these tests for IS_ERR(), which won?t catch NULL pointers, and are instead testing for conditions that can never happen?
> <4>RSP: 0018:ffff880467731cb0 EFLAGS: 00010282
> <4>RAX: ffff880467730000 RBX: ffff88046811e000 RCX: ffff88046313a040
> <4>RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> <4>RBP: ffff880467731ce0 R08: ffff880467731c78 R09: 0000000000000000
> <4>R10: 0000000000000000 R11: 0000000000000000 R12: ffff88046811e210
> <4>R13: 0000000000000000 R14: ffff880466696400 R15: ffffe8ffffb01d08
> <4>FS: 0000000000000000(0000) GS:ffff880036900000(0000) knlGS:0000000000000000
> <4>CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> <4>CR2: 0000000000000040 CR3: 00000004624b8000 CR4: 00000000000007e0
> <4>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> <4>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> <4>Process events/8 (pid: 1697, threadinfo ffff880467730000, task ffff88046313a040)
> <4>Stack:
> <4> ffff8804679cd5b8 ffff88046811e000 ffff88046811e210 0000000000000000
> <4><d> ffff880466696400 ffffe8ffffb01d08 ffff880467731d00 ffffffffa0588f51
> <4><d> ffff8804679cd5e0 ffff8804679cd598 ffff880467731e10 ffffffffa02e9e75
> <4>Call Trace:
> <4> [<ffffffffa0588f51>] rdma_destroy_qp+0x31/0x50 [rdma_cm]
> <4> [<ffffffffa02e9e75>] rpcrdma_ep_connect+0x135/0x3e0 [xprtrdma]
> <4> [<ffffffff8150d6e0>] ? thread_return+0x4e/0x76e
> <4> [<ffffffffa05d06ae>] ? rpc_wake_up_task_queue_locked+0x18e/0x270 [sunrpc]
> <4> [<ffffffffa02e6ff0>] ? xprt_rdma_connect_worker+0x0/0xc0 [xprtrdma]
> <4> [<ffffffffa02e7032>] xprt_rdma_connect_worker+0x42/0xc0 [xprtrdma]
> <4> [<ffffffff81090ac0>] worker_thread+0x170/0x2a0
> <4> [<ffffffff81096c80>] ? autoremove_wake_function+0x0/0x40
> <4> [<ffffffff81090950>] ? worker_thread+0x0/0x2a0
> <4> [<ffffffff81096916>] kthread+0x96/0xa0
> <4> [<ffffffff8100c0ca>] child_rip+0xa/0x20
> <4> [<ffffffff81096880>] ? kthread+0x0/0xa0
> <4> [<ffffffff8100c0c0>] ? child_rip+0x0/0x20
> <4>Code: 65 f0 4c 8b 6d f8 c9 c3 66 90 55 48 89 e5 48 83 ec 30 48 89 5d d8 4c 89 65 e0 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 0f 1f 44 00 00 <8b> 57 40 b8 f0 ff ff ff 49 89 fe 85 d2 75 39 4c 8b 67 58 49 39
> <1>RIP [<ffffffffa0265451>] ib_destroy_qp+0x21/0x120 [ib_core]
> <4> RSP <ffff880467731cb0>
> <4>CR2: 0000000000000040
>
> -----Original Message-----
> From: Trond Myklebust [mailto:[email protected]]
> Sent: Tuesday, April 08, 2014 5:31 AM
> To: Devesh Sharma
> Cc: [email protected]; [email protected]
> Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
>
>
> On Apr 7, 2014, at 19:45, Devesh Sharma <[email protected]> wrote:
>
>> Hi
>> Inline Below:
>>
>> -----Original Message-----
>> From: Trond Myklebust [mailto:[email protected]]
>> Sent: Tuesday, April 08, 2014 4:58 AM
>> To: Devesh Sharma
>> Cc: [email protected]; [email protected]
>> Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks
>>
>>
>> On Apr 7, 2014, at 18:30, [email protected] wrote:
>>
>>> From: Devesh Sharma <[email protected]>
>>>
>>> If the rdma_create_qp fails to create qp due to device firmware being
>>> in invalid state xprtrdma still tries to destroy the non-existant qp
>>> and ends up in a NULL pointer reference crash.
>>> Adding proper checks for vaidating QP pointer avoids this to happen.
>>>
>>
>> As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing?
>> [DS]: If you focus on rpcrdma_ep_connect() function and assume that rdma_create_qp() has failed with some valid error code, then this callback function will return ep->rep_connected = some non-zero.
>> Eventually xprt_rdma_connect_worker() will call rpcrdma_ep_connect()
>> again and rpcrdma_ep_connect will try to free-up all the resources, now rdma_destroy_qp() will be called with invalid QP (which is NULL) pointer And hence kernel will panic. Please correct me if I am worng.
>>
>
> AFAICS your patch does nothing to address that problem. Instead it adds tests for IS_ERR(ia->ri_id->qp), which can never happen because ia->ri_id->qp is either NULL or points to a valid structure.
>
> _________________________________
> Trond Myklebust
> Linux NFS client maintainer, PrimaryData [email protected]
>
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData
[email protected]
On Apr 7, 2014, at 18:30, [email protected] wrote:
> From: Devesh Sharma <[email protected]>
>
> If the rdma_create_qp fails to create qp due to device firmware being in invalid state
> xprtrdma still tries to destroy the non-existant qp and ends up in a NULL pointer reference
> crash.
> Adding proper checks for vaidating QP pointer avoids this to happen.
>
As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing?
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData
[email protected]