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| author |   Jack Morgenstein <jackm@dev.mellanox.co.il> | 2018-01-28 11:25:29 +0200 |
|---|---|---|
| committer |   Jason Gunthorpe <jgg@mellanox.com> | 2018-01-28 14:07:16 -0700 |
| commit | f23a5350e43c810ca36b26d4ed4ecd9a08686f47 (patch) | |
| tree | 406ff11e72f879d5352798589affc1c3d76cd5f9 /drivers/infiniband/core | |
| parent | IB/iser: Combine substrings for three messages (diff) | |
| download | linux-dev-f23a5350e43c810ca36b26d4ed4ecd9a08686f47.tar.xz linux-dev-f23a5350e43c810ca36b26d4ed4ecd9a08686f47.zip | |
IB/umad: Fix use of unprotected device pointer
The ib_write_umad() is protected by taking the umad file mutex.
However, it accesses file->port->ib_dev -- which is protected only by the
port's mutex (field file_mutex).
The ib_umad_remove_one() calls ib_umad_kill_port() which sets
port->ib_dev to NULL under the port mutex (NOT the file mutex).
It then sets the mad agent to "dead" under the umad file mutex.
This is a race condition -- because there is a window where
port->ib_dev is NULL, while the agent is not "dead".
As a result, we saw stack traces like:
[16490.678059] BUG: unable to handle kernel NULL pointer dereference at 00000000000000b0
[16490.678246] IP: ib_umad_write+0x29c/0xa3a [ib_umad]
[16490.678333] PGD 0 P4D 0
[16490.678404] Oops: 0000 [#1] SMP PTI
[16490.678466] Modules linked in: rdma_ucm(OE) ib_ucm(OE) rdma_cm(OE) iw_cm(OE) ib_ipoib(OE) ib_cm(OE) ib_uverbs(OE) ib_umad(OE) mlx4_en(OE) ptp pps_core mlx4_ib(OE-) ib_core(OE) mlx4_core(OE) mlx_compat
(OE) memtrack(OE) devlink mst_pciconf(OE) mst_pci(OE) netconsole nfsv3 nfs_acl nfs lockd grace fscache cfg80211 rfkill esp6_offload esp6 esp4_offload esp4 sunrpc kvm_intel kvm ppdev parport_pc irqbypass
parport joydev i2c_piix4 virtio_balloon cirrus drm_kms_helper ttm drm e1000 serio_raw virtio_pci virtio_ring virtio ata_generic pata_acpi qemu_fw_cfg [last unloaded: mlxfw]
[16490.679202] CPU: 4 PID: 3115 Comm: sminfo Tainted: G OE 4.14.13-300.fc27.x86_64 #1
[16490.679339] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu2 04/01/2014
[16490.679477] task: ffff9cf753890000 task.stack: ffffaf70c26b0000
[16490.679571] RIP: 0010:ib_umad_write+0x29c/0xa3a [ib_umad]
[16490.679664] RSP: 0018:ffffaf70c26b3d90 EFLAGS: 00010202
[16490.679747] RAX: 0000000000000010 RBX: ffff9cf75610fd80 RCX: 0000000000000000
[16490.679856] RDX: 0000000000000001 RSI: 00007ffdf2bfd714 RDI: ffff9cf6bb2a9c00
In the above trace, ib_umad_write is trying to dereference the NULL
file->port->ib_dev pointer.
Fix this by using the agent's device pointer (the device field
in struct ib_mad_agent) -- which IS protected by the umad file mutex.
Cc: <stable@vger.kernel.org> # v4.11
Fixes: 44c58487d51a ("IB/core: Define 'ib' and 'roce' rdma_ah_attr types")
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'drivers/infiniband/core')
| -rw-r--r-- | drivers/infiniband/core/user_mad.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index f0ed883492ec..5e8ffd12c04e 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -511,7 +511,7 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf, } memset(&ah_attr, 0, sizeof ah_attr); - ah_attr.type = rdma_ah_find_type(file->port->ib_dev, + ah_attr.type = rdma_ah_find_type(agent->device, file->port->port_num); rdma_ah_set_dlid(&ah_attr, be16_to_cpu(packet->mad.hdr.lid)); rdma_ah_set_sl(&ah_attr, packet->mad.hdr.sl); |