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Eric Dumazet b316280c81 bpf: fix lockdep splat 
[ Upstream commit 89ad2fa3f0 ]

pcpu_freelist_pop() needs the same lockdep awareness than
pcpu_freelist_populate() to avoid a false positive.

 [ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]

 switchto-defaul/12508 [HC0[0]:SC0[6]:HE0:SE0] is trying to acquire:
  (&htab->buckets[i].lock){......}, at: [<ffffffff9dc099cb>] __htab_percpu_map_update_elem+0x1cb/0x300

 and this task is already holding:
  (dev_queue->dev->qdisc_class ?: &qdisc_tx_lock#2){+.-...}, at: [<ffffffff9e135848>] __dev_queue_xmit+0
x868/0x1240
 which would create a new lock dependency:
  (dev_queue->dev->qdisc_class ?: &qdisc_tx_lock#2){+.-...} -> (&htab->buckets[i].lock){......}

 but this new dependency connects a SOFTIRQ-irq-safe lock:
  (dev_queue->dev->qdisc_class ?: &qdisc_tx_lock#2){+.-...}
 ... which became SOFTIRQ-irq-safe at:
   [<ffffffff9db5931b>] __lock_acquire+0x42b/0x1f10
   [<ffffffff9db5b32c>] lock_acquire+0xbc/0x1b0
   [<ffffffff9da05e38>] _raw_spin_lock+0x38/0x50
   [<ffffffff9e135848>] __dev_queue_xmit+0x868/0x1240
   [<ffffffff9e136240>] dev_queue_xmit+0x10/0x20
   [<ffffffff9e1965d9>] ip_finish_output2+0x439/0x590
   [<ffffffff9e197410>] ip_finish_output+0x150/0x2f0
   [<ffffffff9e19886d>] ip_output+0x7d/0x260
   [<ffffffff9e19789e>] ip_local_out+0x5e/0xe0
   [<ffffffff9e197b25>] ip_queue_xmit+0x205/0x620
   [<ffffffff9e1b8398>] tcp_transmit_skb+0x5a8/0xcb0
   [<ffffffff9e1ba152>] tcp_write_xmit+0x242/0x1070
   [<ffffffff9e1baffc>] __tcp_push_pending_frames+0x3c/0xf0
   [<ffffffff9e1b3472>] tcp_rcv_established+0x312/0x700
   [<ffffffff9e1c1acc>] tcp_v4_do_rcv+0x11c/0x200
   [<ffffffff9e1c3dc2>] tcp_v4_rcv+0xaa2/0xc30
   [<ffffffff9e191107>] ip_local_deliver_finish+0xa7/0x240
   [<ffffffff9e191a36>] ip_local_deliver+0x66/0x200
   [<ffffffff9e19137d>] ip_rcv_finish+0xdd/0x560
   [<ffffffff9e191e65>] ip_rcv+0x295/0x510
   [<ffffffff9e12ff88>] __netif_receive_skb_core+0x988/0x1020
   [<ffffffff9e130641>] __netif_receive_skb+0x21/0x70
   [<ffffffff9e1306ff>] process_backlog+0x6f/0x230
   [<ffffffff9e132129>] net_rx_action+0x229/0x420
   [<ffffffff9da07ee8>] __do_softirq+0xd8/0x43d
   [<ffffffff9e282bcc>] do_softirq_own_stack+0x1c/0x30
   [<ffffffff9dafc2f5>] do_softirq+0x55/0x60
   [<ffffffff9dafc3a8>] __local_bh_enable_ip+0xa8/0xb0
   [<ffffffff9db4c727>] cpu_startup_entry+0x1c7/0x500
   [<ffffffff9daab333>] start_secondary+0x113/0x140

 to a SOFTIRQ-irq-unsafe lock:
  (&head->lock){+.+...}
 ... which became SOFTIRQ-irq-unsafe at:
 ...  [<ffffffff9db5971f>] __lock_acquire+0x82f/0x1f10
   [<ffffffff9db5b32c>] lock_acquire+0xbc/0x1b0
   [<ffffffff9da05e38>] _raw_spin_lock+0x38/0x50
   [<ffffffff9dc0b7fa>] pcpu_freelist_pop+0x7a/0xb0
   [<ffffffff9dc08b2c>] htab_map_alloc+0x50c/0x5f0
   [<ffffffff9dc00dc5>] SyS_bpf+0x265/0x1200
   [<ffffffff9e28195f>] entry_SYSCALL_64_fastpath+0x12/0x17

 other info that might help us debug this:

 Chain exists of:
   dev_queue->dev->qdisc_class ?: &qdisc_tx_lock#2 --> &htab->buckets[i].lock --> &head->lock

  Possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&head->lock);
                                local_irq_disable();
                                lock(dev_queue->dev->qdisc_class ?: &qdisc_tx_lock#2);
                                lock(&htab->buckets[i].lock);
   <Interrupt>
     lock(dev_queue->dev->qdisc_class ?: &qdisc_tx_lock#2);

  *** DEADLOCK ***

Fixes: e19494edab ("bpf: introduce percpu_freelist")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2017-12-14 09:53:11 +01:00
arch sparc64/mm: set fields in deferred pages 2017-12-14 09:53:10 +01:00
block block: wake up all tasks blocked in get_request() 2017-12-14 09:53:10 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto X.509: fix comparisons of ->pkey_algo 2017-12-14 09:52:53 +01:00
Documentation dt-bindings: usb: fix reg-property port-number range 2017-12-14 09:53:09 +01:00
drivers geneve: fix fill_info when link down 2017-12-14 09:53:11 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs fcntl: don't leak fd reference when fixup_compat_flock fails 2017-12-14 09:53:11 +01:00
include lib/genalloc.c: make the avail variable an atomic_long_t 2017-12-14 09:53:08 +01:00
init License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel bpf: fix lockdep splat 2017-12-14 09:53:11 +01:00
lib dynamic-debug-howto: fix optional/omitted ending line number to be LARGE instead of 0 2017-12-14 09:53:08 +01:00
mm slub: fix sysfs duplicate filename creation when slub_debug=O 2017-12-14 09:53:10 +01:00
net sctp: use the right sk after waking up from wait_buf sleep 2017-12-14 09:53:11 +01:00
samples License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
scripts coccinelle: fix parallel build with CHECK=scripts/coccicheck 2017-12-14 09:53:06 +01:00
security apparmor: fix leak of null profile name if profile allocation fails 2017-12-14 09:53:06 +01:00
sound ALSA: usb-audio: Add check return value for usb_string() 2017-12-14 09:52:55 +01:00
tools x86/mpx/selftests: Fix up weird arrays 2017-12-14 09:53:06 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: vgic-its: Check result of allocation before use 2017-12-14 09:53:01 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14.5 2017-12-10 13:40:45 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

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
``make pdfdocs``.

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.