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Eric Dumazet 2695578b89 net: usbnet: fix potential deadlock on 32bit hosts
Marek reported a LOCKDEP issue occurring on 32bit host,
that we tracked down to the fact that usbnet could either
run from soft or hard irqs.

This patch adds u64_stats_update_begin_irqsave() and
u64_stats_update_end_irqrestore() helpers to solve this case.

[   17.768040] ================================
[   17.772239] WARNING: inconsistent lock state
[   17.776511] 4.16.0-rc3-next-20180227-00007-g876c53a7493c #453 Not tainted
[   17.783329] --------------------------------
[   17.787580] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[   17.793607] swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[   17.798751]  (&syncp->seq#5){?.-.}, at: [<9b22e5f0>]
asix_rx_fixup_internal+0x188/0x288
[   17.806790] {IN-HARDIRQ-W} state was registered at:
[   17.811677]   tx_complete+0x100/0x208
[   17.815319]   __usb_hcd_giveback_urb+0x60/0xf0
[   17.819770]   xhci_giveback_urb_in_irq+0xa8/0x240
[   17.824469]   xhci_td_cleanup+0xf4/0x16c
[   17.828367]   xhci_irq+0xe74/0x2240
[   17.831827]   usb_hcd_irq+0x24/0x38
[   17.835343]   __handle_irq_event_percpu+0x98/0x510
[   17.840111]   handle_irq_event_percpu+0x1c/0x58
[   17.844623]   handle_irq_event+0x38/0x5c
[   17.848519]   handle_fasteoi_irq+0xa4/0x138
[   17.852681]   generic_handle_irq+0x18/0x28
[   17.856760]   __handle_domain_irq+0x6c/0xe4
[   17.860941]   gic_handle_irq+0x54/0xa0
[   17.864666]   __irq_svc+0x70/0xb0
[   17.867964]   arch_cpu_idle+0x20/0x3c
[   17.871578]   arch_cpu_idle+0x20/0x3c
[   17.875190]   do_idle+0x144/0x218
[   17.878468]   cpu_startup_entry+0x18/0x1c
[   17.882454]   start_kernel+0x394/0x400
[   17.886177] irq event stamp: 161912
[   17.889616] hardirqs last  enabled at (161912): [<7bedfacf>]
__netdev_alloc_skb+0xcc/0x140
[   17.897893] hardirqs last disabled at (161911): [<d58261d0>]
__netdev_alloc_skb+0x94/0x140
[   17.904903] exynos5-hsi2c 12ca0000.i2c: tx timeout
[   17.906116] softirqs last  enabled at (161904): [<387102ff>]
irq_enter+0x78/0x80
[   17.906123] softirqs last disabled at (161905): [<cf4c628e>]
irq_exit+0x134/0x158
[   17.925722].
[   17.925722] other info that might help us debug this:
[   17.933435]  Possible unsafe locking scenario:
[   17.933435].
[   17.940331]        CPU0
[   17.942488]        ----
[   17.944894]   lock(&syncp->seq#5);
[   17.948274]   <Interrupt>
[   17.950847]     lock(&syncp->seq#5);
[   17.954386].
[   17.954386]  *** DEADLOCK ***
[   17.954386].
[   17.962422] no locks held by swapper/0/0.

Fixes: c8b5d129ee ("net: usbnet: support 64bit stats")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-07 11:46:39 -05:00
arch More atomic cleanup from willy. Fix a python script to work with version 3. 2018-03-05 20:31:14 -08:00
block for-linus-20180302 2018-03-02 09:35:36 -08:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto X.509: fix NULL dereference when restricting key with unsupported_sig 2018-02-22 14:38:34 +00:00
Documentation dt-bindings: net: renesas-ravb: Make stream buffer optional 2018-03-07 10:22:38 -05:00
drivers net: usbnet: fix potential deadlock on 32bit hosts 2018-03-07 11:46:39 -05:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs for-4.16-rc3-tag 2018-03-04 11:04:27 -08:00
include net: usbnet: fix potential deadlock on 32bit hosts 2018-03-07 11:46:39 -05:00
init jump_label: Explicitly disable jump labels in __init code 2018-02-21 16:54:05 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-03-05 11:29:24 -08:00
lib test_rhashtable: add test case for rhltable with duplicate objects 2018-03-07 10:44:03 -05:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm mm: don't defer struct page initialization for Xen pv guests 2018-02-21 15:35:43 -08:00
net sch_netem: fix skb leak in netem_enqueue() 2018-03-07 11:18:14 -05:00
samples - do not build samples when cross compiling (Michal Hocko) 2018-02-27 10:39:29 -08:00
scripts Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
security integrity/security: fix digsig.c build error with header file 2018-02-22 20:09:08 -08:00
sound ALSA: x86: Fix potential crash at error path 2018-02-28 08:46:00 +01:00
tools linux-kselftest-4.16-rc5 2018-03-05 11:57:06 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: mmu: Fix overlap between public and private memslots 2018-02-24 01:43:36 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: ignore ASN.1 auto generated files 2018-02-14 21:05:38 +01:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
Makefile Linux 4.16-rc4 2018-03-04 14:54:11 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
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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.