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Michael Braun d8861bab48 gianfar: fix jumbo packets+napi+rx overrun crash
When using jumbo packets and overrunning rx queue with napi enabled,
the following sequence is observed in gfar_add_rx_frag:

   | lstatus                              |       | skb                   |
t  | lstatus,  size, flags                | first | len, data_len, *ptr   |
---+--------------------------------------+-------+-----------------------+
13 | 18002348, 9032, INTERRUPT LAST       | 0     | 9600, 8000,  f554c12e |
12 | 10000640, 1600, INTERRUPT            | 0     | 8000, 6400,  f554c12e |
11 | 10000640, 1600, INTERRUPT            | 0     | 6400, 4800,  f554c12e |
10 | 10000640, 1600, INTERRUPT            | 0     | 4800, 3200,  f554c12e |
09 | 10000640, 1600, INTERRUPT            | 0     | 3200, 1600,  f554c12e |
08 | 14000640, 1600, INTERRUPT FIRST      | 0     | 1600, 0,     f554c12e |
07 | 14000640, 1600, INTERRUPT FIRST      | 1     | 0,    0,     f554c12e |
06 | 1c000080, 128,  INTERRUPT LAST FIRST | 1     | 0,    0,     abf3bd6e |
05 | 18002348, 9032, INTERRUPT LAST       | 0     | 8000, 6400,  c5a57780 |
04 | 10000640, 1600, INTERRUPT            | 0     | 6400, 4800,  c5a57780 |
03 | 10000640, 1600, INTERRUPT            | 0     | 4800, 3200,  c5a57780 |
02 | 10000640, 1600, INTERRUPT            | 0     | 3200, 1600,  c5a57780 |
01 | 10000640, 1600, INTERRUPT            | 0     | 1600, 0,     c5a57780 |
00 | 14000640, 1600, INTERRUPT FIRST      | 1     | 0,    0,     c5a57780 |

So at t=7 a new packets is started but not finished, probably due to rx
overrun - but rx overrun is not indicated in the flags. Instead a new
packets starts at t=8. This results in skb->len to exceed size for the LAST
fragment at t=13 and thus a negative fragment size added to the skb.

This then crashes:

kernel BUG at include/linux/skbuff.h:2277!
Oops: Exception in kernel mode, sig: 5 [#1]
...
NIP [c04689f4] skb_pull+0x2c/0x48
LR [c03f62ac] gfar_clean_rx_ring+0x2e4/0x844
Call Trace:
[ec4bfd38] [c06a84c4] _raw_spin_unlock_irqrestore+0x60/0x7c (unreliable)
[ec4bfda8] [c03f6a44] gfar_poll_rx_sq+0x48/0xe4
[ec4bfdc8] [c048d504] __napi_poll+0x54/0x26c
[ec4bfdf8] [c048d908] net_rx_action+0x138/0x2c0
[ec4bfe68] [c06a8f34] __do_softirq+0x3a4/0x4fc
[ec4bfed8] [c0040150] run_ksoftirqd+0x58/0x70
[ec4bfee8] [c0066ecc] smpboot_thread_fn+0x184/0x1cc
[ec4bff08] [c0062718] kthread+0x140/0x144
[ec4bff38] [c0012350] ret_from_kernel_thread+0x14/0x1c

This patch fixes this by checking for computed LAST fragment size, so a
negative sized fragment is never added.
In order to prevent the newer rx frame from getting corrupted, the FIRST
flag is checked to discard the incomplete older frame.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-05 13:13:32 -08:00
arch Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2021-02-26 13:16:31 -08:00
block for-5.12/block-ipi-2021-02-21 2021-02-22 10:53:05 -08:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto Keyrings miscellany 2021-02-23 16:09:23 -08:00
Documentation docs: networking: drop special stable handling 2021-03-03 08:49:08 -08:00
drivers gianfar: fix jumbo packets+napi+rx overrun crash 2021-03-05 13:13:32 -08:00
fs Miscellaneous ext4 cleanups and bug fixes. Pretty boring this 2021-02-25 10:06:55 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2021-03-05 12:29:36 -08:00
init Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel bpf: Explicitly zero-extend R0 after 32-bit cmpxchg 2021-03-04 19:06:03 -08:00
lib Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/hugetlb: change hugetlb_reserve_pages() to type bool 2021-02-24 13:38:35 -08:00
net CIPSO: Fix unaligned memory access in cipso_v4_gentag_hdr 2021-03-05 13:00:38 -08:00
samples samples, bpf: Add missing munmap in xdpsock 2021-03-04 15:53:32 +01:00
scripts Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
security Keyrings miscellany 2021-02-23 16:09:23 -08:00
sound ARM updates for 5.12-rc1: 2021-02-22 14:27:07 -08:00
tools selftest/net/ipsec.c: Remove unneeded semicolon 2021-03-05 13:00:38 -08:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM/arm64 fixes for 5.11, take #2 2021-02-12 14:07:39 +00:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.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 clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-02-21 17:23:56 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: update email address and home address 2021-01-27 21:03:50 +02:00
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 wireless-drivers fixes for v5.12 2021-02-26 13:17:44 -08:00
Makefile Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
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.