44a5cd436e
If flower filter is created without the skip_sw flag, fl_mask_put() can race with fl_classify() and we can destroy the mask rhashtable while a lookup operation is accessing it. BUG: unable to handle kernel paging request at 00000000000911d1 PGD 0 P4D 0 SMP PTI CPU: 3 PID: 5582 Comm: vhost-5541 Not tainted 4.18.0-rc1.vanilla+ #1950 Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.1.7 06/16/2016 RIP: 0010:rht_bucket_nested+0x20/0x60 Code: 31 c8 c1 c1 18 29 c8 c3 66 90 8b 4f 04 ba 01 00 00 00 8b 07 48 8b bf 80 00 00 0 RSP: 0018:ffffafc5cfbb7a48 EFLAGS: 00010206 RAX: 0000000000001978 RBX: ffff9f12dff88a00 RCX: 00000000ffff9f12 RDX: 00000000000911d1 RSI: 0000000000000148 RDI: 0000000000000001 RBP: ffff9f12dff88a00 R08: 000000005f1cc119 R09: 00000000a715fae2 R10: ffffafc5cfbb7aa8 R11: ffff9f1cb4be804e R12: ffff9f1265e13000 R13: 0000000000000000 R14: ffffafc5cfbb7b48 R15: ffff9f12dff88b68 FS: 0000000000000000(0000) GS:ffff9f1d3f0c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000911d1 CR3: 0000001575a94006 CR4: 00000000001626e0 Call Trace: fl_lookup+0x134/0x140 [cls_flower] fl_classify+0xf3/0x180 [cls_flower] tcf_classify+0x78/0x150 __netif_receive_skb_core+0x69e/0xa50 netif_receive_skb_internal+0x42/0xf0 tun_get_user+0xdd5/0xfd0 [tun] tun_sendmsg+0x52/0x70 [tun] handle_tx+0x2b3/0x5f0 [vhost_net] vhost_worker+0xab/0x100 [vhost] kthread+0xf8/0x130 ret_from_fork+0x35/0x40 Modules linked in: act_mirred act_gact cls_flower vhost_net vhost tap sch_ingress CR2: 00000000000911d1 Fix the above waiting for a RCU grace period before destroying the rhashtable: we need to use tcf_queue_work(), as rhashtable_destroy() must run in process context, as pointed out by Cong Wang. v1 -> v2: use tcf_queue_work to run rhashtable_destroy(). Fixes: 05cd271fd61a ("cls_flower: Support multiple masks per priority") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.