Jason Gunthorpe 39c011a538 RDMA/uverbs: Fix a race with disassociate and exit_mmap()
If uverbs_user_mmap_disassociate() is called while the mmap is
concurrently doing exit_mmap then the ordering of the
rdma_user_mmap_entry_put() is not reliable.

The put must be done before uvers_user_mmap_disassociate() returns,
otherwise there can be a use after free on the ucontext, and a left over
entry in the xarray. If the put is not done here then it is done during
rdma_umap_close() later.

Add the missing put to the error exit path.

  WARNING: CPU: 7 PID: 7111 at drivers/infiniband/core/rdma_core.c:810 uverbs_destroy_ufile_hw+0x2a5/0x340 [ib_uverbs]
  Modules linked in: bonding ipip tunnel4 geneve ip6_udp_tunnel udp_tunnel ip6_gre ip6_tunnel tunnel6 ip_gre ip_tunnel gre mlx5_ib mlx5_core mlxfw pci_hyperv_intf act_ct nf_flow_table ptp pps_core rdma_ucm ib_uverbs ib_ipoib ib_umad 8021q garp mrp openvswitch nsh nf_conncount nfsv3 nfs_acl xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype iptable_filter xt_conntrack br_netfilter bridge stp llc rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache overlay rpcrdma ib_isert iscsi_target_mod ib_iser kvm_intel ib_srpt iTCO_wdt target_core_mod iTCO_vendor_support kvm ib_srp nf_nat irqbypass crc32_pclmul crc32c_intel nf_conntrack rfkill nf_defrag_ipv6 virtio_net nf_defrag_ipv4 pcspkr ghash_clmulni_intel i2c_i801 net_failover failover i2c_core lpc_ich mfd_core rdma_cm ib_cm iw_cm button ib_core sunrpc sch_fq_codel ip_tables serio_raw [last unloaded: tunnel4]
  CPU: 7 PID: 7111 Comm: python3 Tainted: G        W         5.6.0-rc6-for-upstream-dbg-2020-03-21_06-41-26-18 #1
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
  RIP: 0010:uverbs_destroy_ufile_hw+0x2a5/0x340 [ib_uverbs]
  Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 74 49 8b 84 24 08 01 00 00 48 85 c0 0f 84 13 ff ff ff 48 89 ef ff d0 e9 09 ff ff ff <0f> 0b e9 77 ff ff ff e8 0f d8 fa e0 e9 c5 fd ff ff e8 05 d8 fa e0
  RSP: 0018:ffff88840e0779a0 EFLAGS: 00010286
  RAX: dffffc0000000000 RBX: ffff8882a7721c00 RCX: 0000000000000000
  RDX: 1ffff11054ee469f RSI: ffffffff8446d7e0 RDI: ffff8882a77234f8
  RBP: ffff8882a7723400 R08: ffffed1085c0112c R09: 0000000000000001
  R10: 0000000000000001 R11: ffffed1085c0112b R12: ffff888403c30000
  R13: 0000000000000002 R14: ffff8882a7721cb0 R15: ffff8882a7721cd0
  FS:  00007f2046089700(0000) GS:ffff88842de00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f7cfe9a6e20 CR3: 000000040b8ac006 CR4: 0000000000360ee0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   ib_uverbs_remove_one+0x273/0x480 [ib_uverbs]
   ? up_write+0x15c/0x4a0
   remove_client_context+0xa6/0xf0 [ib_core]
   disable_device+0x12d/0x200 [ib_core]
   ? remove_client_context+0xf0/0xf0 [ib_core]
   ? mnt_get_count+0x1d0/0x1d0
   __ib_unregister_device+0x79/0x150 [ib_core]
   ib_unregister_device+0x21/0x30 [ib_core]
   __mlx5_ib_remove+0x91/0x110 [mlx5_ib]
   ? __mlx5_ib_remove+0x110/0x110 [mlx5_ib]
   mlx5_remove_device+0x241/0x310 [mlx5_core]
   mlx5_unregister_device+0x4d/0x1e0 [mlx5_core]
   mlx5_unload_one+0xc0/0x260 [mlx5_core]
   remove_one+0x5c/0x160 [mlx5_core]
   pci_device_remove+0xef/0x2a0
   ? pcibios_free_irq+0x10/0x10
   device_release_driver_internal+0x1d8/0x470
   unbind_store+0x152/0x200
   ? sysfs_kf_write+0x3b/0x180
   ? sysfs_file_ops+0x160/0x160
   kernfs_fop_write+0x284/0x460
   ? __sb_start_write+0x243/0x3a0
   vfs_write+0x197/0x4a0
   ksys_write+0x156/0x1e0
   ? __x64_sys_read+0xb0/0xb0
   ? do_syscall_64+0x73/0x1330
   ? do_syscall_64+0x73/0x1330
   do_syscall_64+0xe7/0x1330
   ? down_write_nested+0x3e0/0x3e0
   ? syscall_return_slowpath+0x970/0x970
   ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe
   ? lockdep_hardirqs_off+0x1de/0x2d0
   ? trace_hardirqs_off_thunk+0x1a/0x1c
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x7f20a3ff0cdb
  Code: 53 48 89 d5 48 89 f3 48 83 ec 18 48 89 7c 24 08 e8 5a fd ff ff 48 89 ea 41 89 c0 48 89 de 48 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 90 fd ff ff 48
  RSP: 002b:00007f2046087040 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
  RAX: ffffffffffffffda RBX: 00007f2038016df0 RCX: 00007f20a3ff0cdb
  RDX: 000000000000000d RSI: 00007f2038016df0 RDI: 0000000000000018
  RBP: 000000000000000d R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000100 R11: 0000000000000293 R12: 00007f2046e29630
  R13: 00007f20280035a0 R14: 0000000000000018 R15: 00007f2038016df0

Fixes: c043ff2cfb ("RDMA: Connect between the mmap entry and the umap_priv structure")
Link: https://lore.kernel.org/r/20200413132136.930388-1-leon@kernel.org
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-04-22 15:43:46 -03:00
2020-02-24 22:43:18 -08:00
2020-04-12 12:35:55 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 3.5 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%