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Vlad Buslov 1253935ad8 net/mlx5e: Fix race condition on nhe->n pointer in neigh update
Current neigh update event handler implementation takes reference to
neighbour structure, assigns it to nhe->n, tries to schedule workqueue task
and releases the reference if task was already enqueued. This results
potentially overwriting existing nhe->n pointer with another neighbour
instance, which causes double release of the instance (once in neigh update
handler that failed to enqueue to workqueue and another one in neigh update
workqueue task that processes updated nhe->n pointer instead of original
one):

[ 3376.512806] ------------[ cut here ]------------
[ 3376.513534] refcount_t: underflow; use-after-free.
[ 3376.521213] Modules linked in: act_skbedit act_mirred act_tunnel_key vxlan ip6_udp_tunnel udp_tunnel nfnetlink act_gact cls_flower sch_ingress openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 mlx5_ib mlx5_core mlxfw pci_hyperv_intf ptp pps_core nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd
 grace fscache ib_isert iscsi_target_mod ib_srpt target_core_mod ib_srp rpcrdma rdma_ucm ib_umad ib_ipoib ib_iser rdma_cm ib_cm iw_cm rfkill ib_uverbs ib_core sunrpc kvm_intel kvm iTCO_wdt iTCO_vendor_support virtio_net irqbypass net_failover crc32_pclmul lpc_ich i2c_i801 failover pcspkr i2c_smbus mfd_core ghash_clmulni_intel sch_fq_codel drm i2c
_core ip_tables crc32c_intel serio_raw [last unloaded: mlxfw]
[ 3376.529468] CPU: 8 PID: 22756 Comm: kworker/u20:5 Not tainted 5.9.0-rc5+ #6
[ 3376.530399] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[ 3376.531975] Workqueue: mlx5e mlx5e_rep_neigh_update [mlx5_core]
[ 3376.532820] RIP: 0010:refcount_warn_saturate+0xd8/0xe0
[ 3376.533589] Code: ff 48 c7 c7 e0 b8 27 82 c6 05 0b b6 09 01 01 e8 94 93 c1 ff 0f 0b c3 48 c7 c7 88 b8 27 82 c6 05 f7 b5 09 01 01 e8 7e 93 c1 ff <0f> 0b c3 0f 1f 44 00 00 8b 07 3d 00 00 00 c0 74 12 83 f8 01 74 13
[ 3376.536017] RSP: 0018:ffffc90002a97e30 EFLAGS: 00010286
[ 3376.536793] RAX: 0000000000000000 RBX: ffff8882de30d648 RCX: 0000000000000000
[ 3376.537718] RDX: ffff8882f5c28f20 RSI: ffff8882f5c18e40 RDI: ffff8882f5c18e40
[ 3376.538654] RBP: ffff8882cdf56c00 R08: 000000000000c580 R09: 0000000000001a4d
[ 3376.539582] R10: 0000000000000731 R11: ffffc90002a97ccd R12: 0000000000000000
[ 3376.540519] R13: ffff8882de30d600 R14: ffff8882de30d640 R15: ffff88821e000900
[ 3376.541444] FS:  0000000000000000(0000) GS:ffff8882f5c00000(0000) knlGS:0000000000000000
[ 3376.542732] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3376.543545] CR2: 0000556e5504b248 CR3: 00000002c6f10005 CR4: 0000000000770ee0
[ 3376.544483] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3376.545419] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3376.546344] PKRU: 55555554
[ 3376.546911] Call Trace:
[ 3376.547479]  mlx5e_rep_neigh_update.cold+0x33/0xe2 [mlx5_core]
[ 3376.548299]  process_one_work+0x1d8/0x390
[ 3376.548977]  worker_thread+0x4d/0x3e0
[ 3376.549631]  ? rescuer_thread+0x3e0/0x3e0
[ 3376.550295]  kthread+0x118/0x130
[ 3376.550914]  ? kthread_create_worker_on_cpu+0x70/0x70
[ 3376.551675]  ret_from_fork+0x1f/0x30
[ 3376.552312] ---[ end trace d84e8f46d2a77eec ]---

Fix the bug by moving work_struct to dedicated dynamically-allocated
structure. This enabled every event handler to work on its own private
neighbour pointer and removes the need for handling the case when task is
already enqueued.

Fixes: 232c001398 ("net/mlx5e: Add support to neighbour update flow")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
2020-10-02 10:59:58 -07:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-09-30 01:49:20 -07:00
block - Fix a regression in bdev partition locking (Christoph) 2020-09-11 11:55:28 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation dt-bindings: net: renesas,ravb: Add support for r8a774e1 SoC 2020-09-27 13:32:06 -07:00
drivers net/mlx5e: Fix race condition on nhe->n pointer in neigh update 2020-10-02 10:59:58 -07:00
fs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-09-22 15:08:41 -07:00
include net/mlx5: cmdif, Avoid skipping reclaim pages if FW is not accessible 2020-10-02 10:59:55 -07:00
init bootconfig: init: make xbc_namebuf static 2020-09-18 22:17:05 -04:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-09-30 01:49:20 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-09-22 14:43:50 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: fix wake_page_function() comment typos 2020-09-20 10:38:47 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-09-30 01:49:20 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts kconfig: qconf: revive help message in the info view 2020-09-20 12:58:54 +09:00
security device_cgroup RCU warning fix from Amol Grover <frextrite@gmail.com> 2020-09-15 16:26:57 -07:00
sound sound fixes for 5.9-rc6 2020-09-18 11:38:08 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-09-30 01:49:20 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap mailmap: add older email addresses for Kees Cook 2020-09-19 13:13:38 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS via-rhine: New device driver maintainer 2020-09-29 14:23:45 -07:00
Makefile Linux 5.9-rc6 2020-09-20 16:33:55 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.