linux-stable.git/include/linux, branch v4.4.210

can: can_dropped_invalid_skb(): ensure an initialized headroom in outgoing CAN sk_buffs

2020-01-14T19:03:03+00:00

commit e7153bf70c3496bac00e7e4f395bb8d8394ac0ea upstream.

KMSAN sysbot detected a read access to an untinitialized value in the
headroom of an outgoing CAN related sk_buff. When using CAN sockets this
area is filled appropriately - but when using a packet socket this
initialization is missing.

The problematic read access occurs in the CAN receive path which can
only be triggered when the sk_buff is sent through a (virtual) CAN
interface. So we check in the sending path whether we need to perform
the missing initializations.

Fixes: d3b58c47d330d ("can: replace timestamp as unique skb attribute")
Reported-by: syzbot+b02ff0707a97e4e79ebb@syzkaller.appspotmail.com
Signed-off-by: Oliver Hartkopp 
Tested-by: Oliver Hartkopp 
Cc: linux-stable  # >= v4.1
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Greg Kroah-Hartman

kobject: Export kobject_get_unless_zero()

2020-01-14T19:02:59+00:00

commit c70c176ff8c3ff0ac6ef9a831cd591ea9a66bd1a upstream.

Make the function available for outside use and fortify it against NULL
kobject.

CC: Greg Kroah-Hartman 
Reviewed-by: Bart Van Assche 
Acked-by: Tejun Heo 
Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

macvlan: do not assume mac_header is set in macvlan_broadcast()

2020-01-12T10:22:52+00:00

[ Upstream commit 96cc4b69581db68efc9749ef32e9cf8e0160c509 ]

Use of eth_hdr() in tx path is error prone.

Many drivers call skb_reset_mac_header() before using it,
but others do not.

Commit 6d1ccff62780 ("net: reset mac header in dev_start_xmit()")
attempted to fix this generically, but commit d346a3fae3ff
("packet: introduce PACKET_QDISC_BYPASS socket option") brought
back the macvlan bug.

Lets add a new helper, so that tx paths no longer have
to call skb_reset_mac_header() only to get a pointer
to skb->data.

Hopefully we will be able to revert 6d1ccff62780
("net: reset mac header in dev_start_xmit()") and save few cycles
in transmit fast path.

BUG: KASAN: use-after-free in __get_unaligned_cpu32 include/linux/unaligned/packed_struct.h:19 [inline]
BUG: KASAN: use-after-free in mc_hash drivers/net/macvlan.c:251 [inline]
BUG: KASAN: use-after-free in macvlan_broadcast+0x547/0x620 drivers/net/macvlan.c:277
Read of size 4 at addr ffff8880a4932401 by task syz-executor947/9579

CPU: 0 PID: 9579 Comm: syz-executor947 Not tainted 5.5.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:145
 __get_unaligned_cpu32 include/linux/unaligned/packed_struct.h:19 [inline]
 mc_hash drivers/net/macvlan.c:251 [inline]
 macvlan_broadcast+0x547/0x620 drivers/net/macvlan.c:277
 macvlan_queue_xmit drivers/net/macvlan.c:520 [inline]
 macvlan_start_xmit+0x402/0x77f drivers/net/macvlan.c:559
 __netdev_start_xmit include/linux/netdevice.h:4447 [inline]
 netdev_start_xmit include/linux/netdevice.h:4461 [inline]
 dev_direct_xmit+0x419/0x630 net/core/dev.c:4079
 packet_direct_xmit+0x1a9/0x250 net/packet/af_packet.c:240
 packet_snd net/packet/af_packet.c:2966 [inline]
 packet_sendmsg+0x260d/0x6220 net/packet/af_packet.c:2991
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 __sys_sendto+0x262/0x380 net/socket.c:1985
 __do_sys_sendto net/socket.c:1997 [inline]
 __se_sys_sendto net/socket.c:1993 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1993
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x442639
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc13549e08 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442639
RDX: 000000000000000e RSI: 0000000020000080 RDI: 0000000000000003
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000403bb0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 9389:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x163/0x770 mm/slab.c:3665
 kmalloc include/linux/slab.h:561 [inline]
 tomoyo_realpath_from_path+0xc5/0x660 security/tomoyo/realpath.c:252
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822
 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129
 security_inode_getattr+0xf2/0x150 security/security.c:1222
 vfs_getattr+0x25/0x70 fs/stat.c:115
 vfs_statx_fd+0x71/0xc0 fs/stat.c:145
 vfs_fstat include/linux/fs.h:3265 [inline]
 __do_sys_newfstat+0x9b/0x120 fs/stat.c:378
 __se_sys_newfstat fs/stat.c:375 [inline]
 __x64_sys_newfstat+0x54/0x80 fs/stat.c:375
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9389:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 tomoyo_realpath_from_path+0x1a7/0x660 security/tomoyo/realpath.c:289
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822
 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129
 security_inode_getattr+0xf2/0x150 security/security.c:1222
 vfs_getattr+0x25/0x70 fs/stat.c:115
 vfs_statx_fd+0x71/0xc0 fs/stat.c:145
 vfs_fstat include/linux/fs.h:3265 [inline]
 __do_sys_newfstat+0x9b/0x120 fs/stat.c:378
 __se_sys_newfstat fs/stat.c:375 [inline]
 __x64_sys_newfstat+0x54/0x80 fs/stat.c:375
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a4932000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1025 bytes inside of
 4096-byte region [ffff8880a4932000, ffff8880a4933000)
The buggy address belongs to the page:
page:ffffea0002924c80 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0
raw: 00fffe0000010200 ffffea0002846208 ffffea00028f3888 ffff8880aa402000
raw: 0000000000000000 ffff8880a4932000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a4932300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a4932380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a4932400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880a4932480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a4932500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: b863ceb7ddce ("[NET]: Add macvlan driver")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

dmaengine: Fix access to uninitialized dma_slave_caps

2020-01-12T10:22:42+00:00

commit 53a256a9b925b47c7e67fc1f16ca41561a7b877c upstream.

dmaengine_desc_set_reuse() allocates a struct dma_slave_caps on the
stack, populates it using dma_get_slave_caps() and then accesses one
of its members.

However dma_get_slave_caps() may fail and this isn't accounted for,
leading to a legitimate warning of gcc-4.9 (but not newer versions):

   In file included from drivers/spi/spi-bcm2835.c:19:0:
   drivers/spi/spi-bcm2835.c: In function 'dmaengine_desc_set_reuse':
>> include/linux/dmaengine.h:1370:10: warning: 'caps.descriptor_reuse' is used uninitialized in this function [-Wuninitialized]
     if (caps.descriptor_reuse) {

Fix it, thereby also silencing the gcc-4.9 warning.

The issue has been present for 4 years but surfaces only now that
the first caller of dmaengine_desc_set_reuse() has been added in
spi-bcm2835.c. Another user of reusable DMA descriptors has existed
for a while in pxa_camera.c, but it sets the DMA_CTRL_REUSE flag
directly instead of calling dmaengine_desc_set_reuse(). Nevertheless,
tag this commit for stable in case there are out-of-tree users.

Fixes: 272420214d26 ("dmaengine: Add DMA_CTRL_REUSE")
Reported-by: kbuild test robot 
Signed-off-by: Lukas Wunner 
Cc: stable@vger.kernel.org # v4.3+
Link: https://lore.kernel.org/r/ca92998ccc054b4f2bfd60ef3adbab2913171eac.1575546234.git.lukas@wunner.de
Signed-off-by: Vinod Koul 
Signed-off-by: Greg Kroah-Hartman

hrtimer: Annotate lockless access to timer->state

2020-01-04T12:34:38+00:00

commit 56144737e67329c9aaed15f942d46a6302e2e3d8 upstream.

syzbot reported various data-race caused by hrtimer_is_queued() reading
timer->state. A READ_ONCE() is required there to silence the warning.

Also add the corresponding WRITE_ONCE() when timer->state is set.

In remove_hrtimer() the hrtimer_is_queued() helper is open coded to avoid
loading timer->state twice.

KCSAN reported these cases:

BUG: KCSAN: data-race in __remove_hrtimer / tcp_pacing_check

write to 0xffff8880b2a7d388 of 1 bytes by interrupt on cpu 0:
 __remove_hrtimer+0x52/0x130 kernel/time/hrtimer.c:991
 __run_hrtimer kernel/time/hrtimer.c:1496 [inline]
 __hrtimer_run_queues+0x250/0x600 kernel/time/hrtimer.c:1576
 hrtimer_run_softirq+0x10e/0x150 kernel/time/hrtimer.c:1593
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 run_ksoftirqd+0x46/0x60 kernel/softirq.c:603
 smpboot_thread_fn+0x37d/0x4a0 kernel/smpboot.c:165
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff8880b2a7d388 of 1 bytes by task 24652 on cpu 1:
 tcp_pacing_check net/ipv4/tcp_output.c:2235 [inline]
 tcp_pacing_check+0xba/0x130 net/ipv4/tcp_output.c:2225
 tcp_xmit_retransmit_queue+0x32c/0x5a0 net/ipv4/tcp_output.c:3044
 tcp_xmit_recovery+0x7c/0x120 net/ipv4/tcp_input.c:3558
 tcp_ack+0x17b6/0x3170 net/ipv4/tcp_input.c:3717
 tcp_rcv_established+0x37e/0xf50 net/ipv4/tcp_input.c:5696
 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1561
 sk_backlog_rcv include/net/sock.h:945 [inline]
 __release_sock+0x135/0x1e0 net/core/sock.c:2435
 release_sock+0x61/0x160 net/core/sock.c:2951
 sk_stream_wait_memory+0x3d7/0x7c0 net/core/stream.c:145
 tcp_sendmsg_locked+0xb47/0x1f30 net/ipv4/tcp.c:1393
 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1434
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657

BUG: KCSAN: data-race in __remove_hrtimer / __tcp_ack_snd_check

write to 0xffff8880a3a65588 of 1 bytes by interrupt on cpu 0:
 __remove_hrtimer+0x52/0x130 kernel/time/hrtimer.c:991
 __run_hrtimer kernel/time/hrtimer.c:1496 [inline]
 __hrtimer_run_queues+0x250/0x600 kernel/time/hrtimer.c:1576
 hrtimer_run_softirq+0x10e/0x150 kernel/time/hrtimer.c:1593
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xbb/0xe0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830

read to 0xffff8880a3a65588 of 1 bytes by task 22891 on cpu 1:
 __tcp_ack_snd_check+0x415/0x4f0 net/ipv4/tcp_input.c:5265
 tcp_ack_snd_check net/ipv4/tcp_input.c:5287 [inline]
 tcp_rcv_established+0x750/0xf50 net/ipv4/tcp_input.c:5708
 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1561
 sk_backlog_rcv include/net/sock.h:945 [inline]
 __release_sock+0x135/0x1e0 net/core/sock.c:2435
 release_sock+0x61/0x160 net/core/sock.c:2951
 sk_stream_wait_memory+0x3d7/0x7c0 net/core/stream.c:145
 tcp_sendmsg_locked+0xb47/0x1f30 net/ipv4/tcp.c:1393
 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1434
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 __sys_sendto+0x21f/0x320 net/socket.c:1952
 __do_sys_sendto net/socket.c:1964 [inline]
 __se_sys_sendto net/socket.c:1960 [inline]
 __x64_sys_sendto+0x89/0xb0 net/socket.c:1960
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24652 Comm: syz-executor.3 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

[ tglx: Added comments ]

Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Signed-off-by: Thomas Gleixner 
Link: https://lkml.kernel.org/r/20191106174804.74723-1-edumazet@google.com
Signed-off-by: Greg Kroah-Hartman

libfdt: define INT32_MAX and UINT32_MAX in libfdt_env.h

2020-01-04T12:34:37+00:00

[ Upstream commit a8de1304b7df30e3a14f2a8b9709bb4ff31a0385 ]

The DTC v1.5.1 added references to (U)INT32_MAX.

This is no problem for user-space programs since  defines
(U)INT32_MAX along with (u)int32_t.

For the kernel space, libfdt_env.h needs to be adjusted before we
pull in the changes.

In the kernel, we usually use s/u32 instead of (u)int32_t for the
fixed-width types.

Accordingly, we already have S/U32_MAX for their max values.
So, we should not add (U)INT32_MAX to  any more.

Instead, add them to the in-kernel libfdt_env.h to compile the
latest libfdt.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Rob Herring 
Signed-off-by: Sasha Levin

fs/quota: handle overflows of sysctl fs.quota.* and report as unsigned long

2020-01-04T12:34:32+00:00

[ Upstream commit 6fcbcec9cfc7b3c6a2c1f1a23ebacedff7073e0a ]

Quota statistics counted as 64-bit per-cpu counter. Reading sums per-cpu
fractions as signed 64-bit int, filters negative values and then reports
lower half as signed 32-bit int.

Result may looks like:

fs.quota.allocated_dquots = 22327
fs.quota.cache_hits = -489852115
fs.quota.drops = -487288718
fs.quota.free_dquots = 22083
fs.quota.lookups = -486883485
fs.quota.reads = 22327
fs.quota.syncs = 335064
fs.quota.writes = 3088689

Values bigger than 2^31-1 reported as negative.

All counters except "allocated_dquots" and "free_dquots" are monotonic,
thus they should be reported as is without filtering negative values.

Kernel doesn't have generic helper for 64-bit sysctl yet,
let's use at least unsigned long.

Link: https://lore.kernel.org/r/157337934693.2078.9842146413181153727.stgit@buzz
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Jan Kara 
Signed-off-by: Sasha Levin

mod_devicetable: fix PHY module format

2020-01-04T12:34:20+00:00

[ Upstream commit d2ed49cf6c13e379c5819aa5ac20e1f9674ebc89 ]

When a PHY is probed, if the top bit is set, we end up requesting a
module with the string "mdio:-10101110000000100101000101010001" -
the top bit is printed to a signed -1 value. This leads to the module
not being loaded.

Fix the module format string and the macro generating the values for
it to ensure that we only print unsigned types and the top bit is
always 0/1. We correctly end up with
"mdio:10101110000000100101000101010001".

Fixes: 8626d3b43280 ("phylib: Support phy module autoloading")
Reviewed-by: Andrew Lunn 
Signed-off-by: Russell King 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: fix rejected syncookies due to stale timestamps

2019-12-21T09:35:40+00:00

[ Upstream commit 04d26e7b159a396372646a480f4caa166d1b6720 ]

If no synflood happens for a long enough period of time, then the
synflood timestamp isn't refreshed and jiffies can advance so much
that time_after32() can't accurately compare them any more.

Therefore, we can end up in a situation where time_after32(now,
last_overflow + HZ) returns false, just because these two values are
too far apart. In that case, the synflood timestamp isn't updated as
it should be, which can trick tcp_synq_no_recent_overflow() into
rejecting valid syncookies.

For example, let's consider the following scenario on a system
with HZ=1000:

  * The synflood timestamp is 0, either because that's the timestamp
    of the last synflood or, more commonly, because we're working with
    a freshly created socket.

  * We receive a new SYN, which triggers synflood protection. Let's say
    that this happens when jiffies == 2147484649 (that is,
    'synflood timestamp' + HZ + 2^31 + 1).

  * Then tcp_synq_overflow() doesn't update the synflood timestamp,
    because time_after32(2147484649, 1000) returns false.
    With:
      - 2147484649: the value of jiffies, aka. 'now'.
      - 1000: the value of 'last_overflow' + HZ.

  * A bit later, we receive the ACK completing the 3WHS. But
    cookie_v[46]_check() rejects it because tcp_synq_no_recent_overflow()
    says that we're not under synflood. That's because
    time_after32(2147484649, 120000) returns false.
    With:
      - 2147484649: the value of jiffies, aka. 'now'.
      - 120000: the value of 'last_overflow' + TCP_SYNCOOKIE_VALID.

    Of course, in reality jiffies would have increased a bit, but this
    condition will last for the next 119 seconds, which is far enough
    to accommodate for jiffie's growth.

Fix this by updating the overflow timestamp whenever jiffies isn't
within the [last_overflow, last_overflow + HZ] range. That shouldn't
have any performance impact since the update still happens at most once
per second.

Now we're guaranteed to have fresh timestamps while under synflood, so
tcp_synq_no_recent_overflow() can safely use it with time_after32() in
such situations.

Stale timestamps can still make tcp_synq_no_recent_overflow() return
the wrong verdict when not under synflood. This will be handled in the
next patch.

For 64 bits architectures, the problem was introduced with the
conversion of ->tw_ts_recent_stamp to 32 bits integer by commit
cca9bab1b72c ("tcp: use monotonic timestamps for PAWS").
The problem has always been there on 32 bits architectures.

Fixes: cca9bab1b72c ("tcp: use monotonic timestamps for PAWS")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Guillaume Nault 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

inet: protect against too small mtu values.

2019-12-21T09:35:40+00:00

[ Upstream commit 501a90c945103e8627406763dac418f20f3837b2 ]

syzbot was once again able to crash a host by setting a very small mtu
on loopback device.

Let's make inetdev_valid_mtu() available in include/net/ip.h,
and use it in ip_setup_cork(), so that we protect both ip_append_page()
and __ip_append_data()

Also add a READ_ONCE() when the device mtu is read.

Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(),
even if other code paths might write over this field.

Add a big comment in include/linux/netdevice.h about dev->mtu
needing READ_ONCE()/WRITE_ONCE() annotations.

Hopefully we will add the missing ones in followup patches.

[1]

refcount_t: saturated; leaking memory.
WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x3e kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22
Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89
RSP: 0018:ffff88809689f550 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c
RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1
R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001
R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40
 refcount_add include/linux/refcount.h:193 [inline]
 skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999
 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096
 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383
 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276
 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821
 kernel_sendpage+0x92/0xf0 net/socket.c:3794
 sock_sendpage+0x8b/0xc0 net/socket.c:936
 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458
 splice_from_pipe_feed fs/splice.c:512 [inline]
 __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636
 splice_from_pipe+0x108/0x170 fs/splice.c:671
 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842
 do_splice_from fs/splice.c:861 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1035
 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078
 do_sendfile+0x597/0xd00 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1525 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441409
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010
R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180
R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Fixes: 1470ddf7f8ce ("inet: Remove explicit write references to sk/inet in ip_append_data")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman