Subject: Re: [PATCH rdma-rc] RDMA/cm: Protect access to remote_sidr_table

From: Jason Gunthorpe <[email-masked]>
Date: Thu, 16 Jul 2020 10:55:50 -0300

On Thu, Jul 16, 2020 at 01:55:19PM +0300, Leon Romanovsky wrote:
> From: Maor Gottlieb <[email-masked]>
> 
> cm.lock must be held while access to remote_sidr_table.
> This fix the below NULL pointer dereference.
> 
>  [ 2666.146138] BUG: kernel NULL pointer dereference, address: 0000000000000000
>  [ 2666.151565] #PF: supervisor write access in kernel mode
>  [ 2666.152896] #PF: error_code(0x0002) - not-present page
>  [ 2666.154184] PGD 0 P4D 0
>  [ 2666.154911] Oops: 0002 [#1] SMP PTI
>  [ 2666.155859] CPU: 2 PID: 7288 Comm: udaddy Not tainted 5.7.0_for_upstream_perf_2020_06_09_15_14_20_38 #1
>  [ 2666.158123] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
>  [ 2666.161909] RIP: 0010:rb_erase+0x10d/0x360
>  [ 2666.163549] Code: 00 00 00 48 89 c1 48 89 d0 48 8b 50 08 48 39 ca 74 48 f6 02 01 75 af 48 8b
> 7a 10 48 89 c1 48 83 c9 01 48 89 78 08 48 89 42 10 <48> 89 0f 48 8b 08 48 89 0a 48 83 e1 fc 48
>  89 10 0f 84 b1 00 00 00
>  [ 2666.169743] RSP: 0018:ffffc90000f77c30 EFLAGS: 00010086
>  [ 2666.171646] RAX: ffff8883df27d458 RBX: ffff8883df27da58 RCX: ffff8883df27d459
>  [ 2666.174026] RDX: ffff8883d183fa58 RSI: ffffffffa01e8d00 RDI: 0000000000000000
>  [ 2666.176325] RBP: ffff8883d62ac800 R08: 0000000000000000 R09: 00000000000000ce
>  [ 2666.178618] R10: 000000000000000a R11: 0000000000000000 R12: ffff8883df27da00
>  [ 2666.180919] R13: ffffc90000f77c98 R14: 0000000000000130 R15: 0000000000000000
>  [ 2666.183197] FS:  00007f009f877740(0000) GS:ffff8883f1a00000(0000) knlGS:0000000000000000
>  [ 2666.186318] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  [ 2666.188293] CR2: 0000000000000000 CR3: 00000003d467e003 CR4: 0000000000160ee0
>  [ 2666.190614] Call Trace:
>  [ 2666.191896]  cm_send_sidr_rep_locked+0x15a/0x1a0 [ib_cm]
>  [ 2666.193902]  ib_send_cm_sidr_rep+0x2b/0x50 [ib_cm]
>  [ 2666.195695]  cma_send_sidr_rep+0x8b/0xe0 [rdma_cm]
>  [ 2666.197559]  __rdma_accept+0x21d/0x2b0 [rdma_cm]
>  [ 2666.199335]  ? ucma_get_ctx+0x2b/0xe0 [rdma_ucm]
>  [ 2666.201105]  ? _copy_from_user+0x30/0x60
>  [ 2666.202741]  ucma_accept+0x13e/0x1e0 [rdma_ucm]
>  [ 2666.204549]  ucma_write+0xb4/0x130 [rdma_ucm]
>  [ 2666.206306]  vfs_write+0xad/0x1a0
>  [ 2666.207780]  ksys_write+0x9d/0xb0
>  [ 2666.209316]  do_syscall_64+0x48/0x130
>  [ 2666.210915]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>  [ 2666.212810] RIP: 0033:0x7f009ef60924
>  [ 2666.214354] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b
> 05 2a ef 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3
>  66 90 55 53 48 89 d5 48 89 f3 48 83
>  [ 2666.220512] RSP: 002b:00007fff843edf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
>  [ 2666.223546] RAX: ffffffffffffffda RBX: 000055743042e1d0 RCX: 00007f009ef60924
>  [ 2666.225889] RDX: 0000000000000130 RSI: 00007fff843edf40 RDI: 0000000000000003
>  [ 2666.228228] RBP: 00007fff843ee0e0 R08: 0000000000000000 R09: 0000557430433090
>  [ 2666.230572] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
>  [ 2666.232931] R13: 00007fff843edf40 R14: 000000000000038c R15: 00000000ffffff00
>  [ 2666.235272] Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5
> auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache xt_MASQUERADE
> mlx5_ib nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype
> iptable_filter bpfilter xt_conntrack br_netfilter bridge stp llc overlay
> rpcrdma ib_isert iscsi_target_mod ib_iser ib_srpt target_core_mod ib_srp
> ib_ipoib rdma_ucm ib_uverbs sb_edac mlx5_core kvm_intel iTCO_wdt
> iTCO_vendor_support kvm ib_umad mlxfw pci_hyperv_intf act_ct
> nf_flow_table irqbypass nf_nat rdma_cm crc32_pclmul rfkill nf_conntrack
> crc32c_intel ghash_clmulni_intel virtio_net ib_cm i2c_i801 pcspkr
> nf_defrag_ipv6 net_failover failover nf_defrag_ipv4 ptp i2c_core lpc_ich
> iw_cm pps_core mfd_core ib_core sunrpc sch_fq_codel ip_tables serio_raw
>  [ 2666.258905] CR2: 0000000000000000
>  [ 2666.260386] ---[ end trace 92a3d3f267f6faa3 ]---
>  [ 2666.262174] RIP: 0010:rb_erase+0x10d/0x360
>  [ 2666.263781] Code: 00 00 00 48 89 c1 48 89 d0 48 8b 50 08 48 39 ca 74
> 48 f6 02 01 75 af 48 8b 7a 10 48 89 c1 48 83 c9 01 48 89 78 08 48 89 42
>    10 <48> 89 0f 48 8b 08 48 89 0a 48 83 e1 fc 48 89 10 0f 84 b1 00 00
>       00
>  [ 2666.269994] RSP: 0018:ffffc90000f77c30 EFLAGS: 00010086
>  [ 2666.272008] RAX: ffff8883df27d458 RBX: ffff8883df27da58 RCX: ffff8883df27d459
>  [ 2666.274465] RDX: ffff8883d183fa58 RSI: ffffffffa01e8d00 RDI: 0000000000000000
>  [ 2666.276978] RBP: ffff8883d62ac800 R08: 0000000000000000 R09: 00000000000000ce
>  [ 2666.279437] R10: 000000000000000a R11: 0000000000000000 R12: ffff8883df27da00
>  [ 2666.281941] R13: ffffc90000f77c98 R14: 0000000000000130 R15: 0000000000000000
>  [ 2666.284397] FS:  00007f009f877740(0000) GS:ffff8883f1a00000(0000) knlGS:0000000000000000
>  [ 2666.287708] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  [ 2666.289817] CR2: 0000000000000000 CR3: 00000003d467e003 CR4: 0000000000160ee0
>  [ 2666.292274] Kernel panic - not syncing: Fatal exception
>  [ 2666.294689] Kernel Offset: disabled
>  [ 2666.296253] ---[ end Kernel panic - not syncing: Fatal exception]---

Don't word wrap oops reports, and I prefer the timestamp is stripped out

> Fixes: 6a8824a74bc9 ("RDMA/cm: Allow ib_send_cm_sidr_rep() to be done under lock")
> Signed-off-by: Maor Gottlieb <[email-masked]>
> Signed-off-by: Leon Romanovsky <[email-masked]>
> ---
>  drivers/infiniband/core/cm.c | 2 ++
>  1 file changed, 2 insertions(+)

Applied to for-rc

Thanks,
Jason