[ Upstream commit cd92d74d ]

clang warns about statically defined DMA masks from the DMA_BIT_MASK
macro with length 64:

arch/arm/plat-orion/common.c:625:29: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
                .coherent_dma_mask      = DMA_BIT_MASK(64),
                                          ^~~~~~~~~~~~~~~~
include/linux/dma-mapping.h:141:54: note: expanded from macro 'DMA_BIT_MASK'
 #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))

The ones in orion shouldn't really be 64 bit masks, so changing them
to what the driver can support avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock

[ Upstream commit 10dce8af ]

Commit 9c225f26 ("vfs: atomic f_pos accesses as per POSIX") added
locking for file.f_pos access and in particular made concurrent read and
write not possible - now both those functions take f_pos lock for the
whole run, and so if e.g. a read is blocked waiting for data, write will
deadlock waiting for that read to complete.

This caused regression for stream-like files where previously read and
write could run simultaneously, but after that patch could not do so
anymore. See e.g. commit 581d21a2 ("xenbus: fix deadlock on writes
to /proc/xen/xenbus") which fixes such regression for particular case of
/proc/xen/xenbus.

The patch that added f_pos lock in 2014 did so to guarantee POSIX thread
safety for read/write/lseek and added the locking to file descriptors of
all regular files. In 2014 that thread-safety problem was not new as it
was already discussed earlier in 2006.

However even though 2006'th version of Linus's patch was adding f_pos
locking "only for files that are marked seekable with FMODE_LSEEK (thus
avoiding the stream-like objects like pipes and sockets)", the 2014
version - the one that actually made it into the tree as 9c225f26 -
is doing so irregardless of whether a file is seekable or not.

See

    https://lore.kernel.org/lkml/53022DB1.4070805@gmail.com/
    https://lwn.net/Articles/180387
    https://lwn.net/Articles/180396

for historic context.

The reason that it did so is, probably, that there are many files that
are marked non-seekable, but e.g. their read implementation actually
depends on knowing current position to correctly handle the read. Some
examples:

	kernel/power/user.c		snapshot_read
	fs/debugfs/file.c		u32_array_read
	fs/fuse/control.c		fuse_conn_waiting_read + ...
	drivers/hwmon/asus_atk0110.c	atk_debugfs_ggrp_read
	arch/s390/hypfs/inode.c		hypfs_read_iter
	...

Despite that, many nonseekable_open users implement read and write with
pure stream semantics - they don't depend on passed ppos at all. And for
those cases where read could wait for something inside, it creates a
situation similar to xenbus - the write could be never made to go until
read is done, and read is waiting for some, potentially external, event,
for potentially unbounded time -> deadlock.

Besides xenbus, there are 14 such places in the kernel that I've found
with semantic patch (see below):

	drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write()
	drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write()
	drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write()
	drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write()
	net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write()
	drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write()
	drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write()
	drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write()
	net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write()
	drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write()
	drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write()
	drivers/input/misc/uinput.c:400:1-17: ERROR: uinput_fops: .read() can deadlock .write()
	drivers/infiniband/core/user_mad.c:985:7-23: ERROR: umad_fops: .read() can deadlock .write()
	drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write()

In addition to the cases above another regression caused by f_pos
locking is that now FUSE filesystems that implement open with
FOPEN_NONSEEKABLE flag, can no longer implement bidirectional
stream-like files - for the same reason as above e.g. read can deadlock
write locking on file.f_pos in the kernel.

FUSE's FOPEN_NONSEEKABLE was added in 2008 in a7c1b990 ("fuse:
implement nonseekable open") to support OSSPD. OSSPD implements /dev/dsp
in userspace with FOPEN_NONSEEKABLE flag, with corresponding read and
write routines not depending on current position at all, and with both
read and write being potentially blocking operations:

See

    https://github.com/libfuse/osspd
    https://lwn.net/Articles/308445

    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1406
    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1438-L1477
    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1479-L1510

Corresponding libfuse example/test also describes FOPEN_NONSEEKABLE as
"somewhat pipe-like files ..." with read handler not using offset.
However that test implements only read without write and cannot exercise
the deadlock scenario:

    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L124-L131
    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L146-L163
    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L209-L216

I've actually hit the read vs write deadlock for real while implementing
my FUSE filesystem where there is /head/watch file, for which open
creates separate bidirectional socket-like stream in between filesystem
and its user with both read and write being later performed
simultaneously. And there it is semantically not easy to split the
stream into two separate read-only and write-only channels:

    https://lab.nexedi.com/kirr/wendelin.core/blob/f13aa600/wcfs/wcfs.go#L88-169

Let's fix this regression. The plan is:

1. We can't change nonseekable_open to include &~FMODE_ATOMIC_POS -
   doing so would break many in-kernel nonseekable_open users which
   actually use ppos in read/write handlers.

2. Add stream_open() to kernel to open stream-like non-seekable file
   descriptors. Read and write on such file descriptors would never use
   nor change ppos. And with that property on stream-like files read and
   write will be running without taking f_pos lock - i.e. read and write
   could be running simultaneously.

3. With semantic patch search and convert to stream_open all in-kernel
   nonseekable_open users for which read and write actually do not
   depend on ppos and where there is no other methods in file_operations
   which assume @offset access.

4. Add FOPEN_STREAM to fs/fuse/ and open in-kernel file-descriptors via
   steam_open if that bit is present in filesystem open reply.

   It was tempting to change fs/fuse/ open handler to use stream_open
   instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but
   grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
   and in particular GVFS which actually uses offset in its read and
   write handlers

	https://codesearch.debian.net/search?q=-%3Enonseekable+%3D
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481

   so if we would do such a change it will break a real user.

5. Add stream_open and FOPEN_STREAM handling to stable kernels starting
   from v3.14+ (the kernel where 9c225f26 first appeared).

   This will allow to patch OSSPD and other FUSE filesystems that
   provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE
   in their open handler and this way avoid the deadlock on all kernel
   versions. This should work because fs/fuse/ ignores unknown open
   flags returned from a filesystem and so passing FOPEN_STREAM to a
   kernel that is not aware of this flag cannot hurt. In turn the kernel
   that is not aware of FOPEN_STREAM will be < v3.14 where just
   FOPEN_NONSEEKABLE is sufficient to implement streams without read vs
   write deadlock.

This patch adds stream_open, converts /proc/xen/xenbus to it and adds
semantic patch to automatically locate in-kernel places that are either
required to be converted due to read vs write deadlock, or that are just
safe to be converted because read and write do not use ppos and there
are no other funky methods in file_operations.

Regarding semantic patch I've verified each generated change manually -
that it is correct to convert - and each other nonseekable_open instance
left - that it is either not correct to convert there, or that it is not
converted due to current stream_open.cocci limitations.

The script also does not convert files that should be valid to convert,
but that currently have .llseek = noop_llseek or generic_file_llseek for
unknown reason despite file being opened with nonseekable_open (e.g.
drivers/input/mousedev.c)

Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yongzhi Pan <panyongzhi@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Nikolaus Rath <Nikolaus@rath.org>
Cc: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 47b16820 ]

If xace hardware reports a bad version number, the error handling code
in ace_setup() calls put_disk(), followed by queue cleanup. However, since
the disk data structure has the queue pointer set, put_disk() also
cleans and releases the queue. This results in blk_cleanup_queue()
accessing an already released data structure, which in turn may result
in a crash such as the following.

[   10.681671] BUG: Kernel NULL pointer dereference at 0x00000040
[   10.681826] Faulting instruction address: 0xc0431480
[   10.682072] Oops: Kernel access of bad area, sig: 11 [#1]
[   10.682251] BE PAGE_SIZE=4K PREEMPT Xilinx Virtex440
[   10.682387] Modules linked in:
[   10.682528] CPU: 0 PID: 1 Comm: swapper Tainted: G        W         5.0.0-rc6-next-20190218+ #2
[   10.682733] NIP:  c0431480 LR: c043147c CTR: c0422ad8
[   10.682863] REGS: cf82fbe0 TRAP: 0300   Tainted: G        W          (5.0.0-rc6-next-20190218+)
[   10.683065] MSR:  00029000 <CE,EE,ME>  CR: 22000222  XER: 00000000
[   10.683236] DEAR: 00000040 ESR: 00000000
[   10.683236] GPR00: c043147c cf82fc90 cf82ccc0 00000000 00000000 00000000 00000002 00000000
[   10.683236] GPR08: 00000000 00000000 c04310bc 00000000 22000222 00000000 c0002c54 00000000
[   10.683236] GPR16: 00000000 00000001 c09aa39c c09021b0 c09021dc 00000007 c0a68c08 00000000
[   10.683236] GPR24: 00000001 ced6d400 ced6dcf0 c0815d9c 00000000 00000000 00000000 cedf0800
[   10.684331] NIP [c0431480] blk_mq_run_hw_queue+0x28/0x114
[   10.684473] LR [c043147c] blk_mq_run_hw_queue+0x24/0x114
[   10.684602] Call Trace:
[   10.684671] [cf82fc90] [c043147c] blk_mq_run_hw_queue+0x24/0x114 (unreliable)
[   10.684854] [cf82fcc0] [c04315bc] blk_mq_run_hw_queues+0x50/0x7c
[   10.685002] [cf82fce0] [c0422b24] blk_set_queue_dying+0x30/0x68
[   10.685154] [cf82fcf0] [c0423ec0] blk_cleanup_queue+0x34/0x14c
[   10.685306] [cf82fd10] [c054d73c] ace_probe+0x3dc/0x508
[   10.685445] [cf82fd50] [c052d740] platform_drv_probe+0x4c/0xb8
[   10.685592] [cf82fd70] [c052abb0] really_probe+0x20c/0x32c
[   10.685728] [cf82fda0] [c052ae58] driver_probe_device+0x68/0x464
[   10.685877] [cf82fdc0] [c052b500] device_driver_attach+0xb4/0xe4
[   10.686024] [cf82fde0] [c052b5dc] __driver_attach+0xac/0xfc
[   10.686161] [cf82fe00] [c0528428] bus_for_each_dev+0x80/0xc0
[   10.686314] [cf82fe30] [c0529b3c] bus_add_driver+0x144/0x234
[   10.686457] [cf82fe50] [c052c46c] driver_register+0x88/0x15c
[   10.686610] [cf82fe60] [c09de288] ace_init+0x4c/0xac
[   10.686742] [cf82fe80] [c0002730] do_one_initcall+0xac/0x330
[   10.686888] [cf82fee0] [c09aafd0] kernel_init_freeable+0x34c/0x478
[   10.687043] [cf82ff30] [c0002c6c] kernel_init+0x18/0x114
[   10.687188] [cf82ff40] [c000f2f0] ret_from_kernel_thread+0x14/0x1c
[   10.687349] Instruction dump:
[   10.687435] 3863ffd4 4bfffd70 9421ffd0 7c0802a6 93c10028 7c9e2378 93e1002c 38810008
[   10.687637] 7c7f1b78 90010034 4bfffc25 813f008c <81290040> 75290100 4182002c 80810008
[   10.688056] ---[ end trace 13c9ff51d41b9d40 ]---

Fix the problem by setting the disk queue pointer to NULL before calling
put_disk(). A more comprehensive fix might be to rearrange the code
to check the hardware version before initializing data structures,
but I don't know if this would have undesirable side effects, and
it would increase the complexity of backporting the fix to older kernels.

Fixes: 74489a91 ("Add support for Xilinx SystemACE CompactFlash interface")
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit acaf892e ]

Many of the sh CPU-types have their own plat_irq_setup() and
arch_init_clk_ops() functions, so these same (empty) functions in
arch/sh/boards/of-generic.c are not needed and cause build errors.

If there is some case where these empty functions are needed, they can
be retained by marking them as "__weak" while at the same time making
builds that do not need them succeed.

Fixes these build errors:

arch/sh/boards/of-generic.o: In function `plat_irq_setup':
(.init.text+0x134): multiple definition of `plat_irq_setup'
arch/sh/kernel/cpu/sh2/setup-sh7619.o:(.init.text+0x30): first defined here
arch/sh/boards/of-generic.o: In function `arch_init_clk_ops':
(.init.text+0x118): multiple definition of `arch_init_clk_ops'
arch/sh/kernel/cpu/sh2/clock-sh7619.o:(.init.text+0x0): first defined here

Link: http://lkml.kernel.org/r/9ee4e0c5-f100-86a2-bd4d-1d3287ceab31@infradead.orgSigned-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 58b6e5e8 ]

When mknod is used to create a block special file in hugetlbfs, it will
allocate an inode and kmalloc a 'struct resv_map' via resv_map_alloc().
inode->i_mapping->private_data will point the newly allocated resv_map.
However, when the device special file is opened bd_acquire() will set
inode->i_mapping to bd_inode->i_mapping.  Thus the pointer to the
allocated resv_map is lost and the structure is leaked.

Programs to reproduce:
        mount -t hugetlbfs nodev hugetlbfs
        mknod hugetlbfs/dev b 0 0
        exec 30<> hugetlbfs/dev
        umount hugetlbfs/

resv_map structures are only needed for inodes which can have associated
page allocations.  To fix the leak, only allocate resv_map for those
inodes which could possibly be associated with page allocations.

Link: http://lkml.kernel.org/r/20190401213101.16476-1-mike.kravetz@oracle.comSigned-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Yufen Yu <yuyufen@huawei.com>
Suggested-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 298a32b1 ]

Commit 2d4f5671 ("KVM: PPC: Introduce kvm_tmp framework") adds
kvm_tmp[] into the .bss section and then free the rest of unused spaces
back to the page allocator.

kernel_init
  kvm_guest_init
    kvm_free_tmp
      free_reserved_area
        free_unref_page
          free_unref_page_prepare

With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel.  As the
result, kmemleak scan will trigger a panic when it scans the .bss
section with unmapped pages.

This patch creates dedicated kmemleak objects for the .data, .bss and
potentially .data..ro_after_init sections to allow partial freeing via
the kmemleak_free_part() in the powerpc kvm_free_tmp() function.

Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@arm.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Qian Cai <cai@lca.pw>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Qian Cai <cai@lca.pw>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit b86bc285 ]

This ensures that the address and length provided to DBG_DECRYPT and
DBG_ENCRYPT do not cause an overflow.

At the same time, pass the actual number of pages pinned in memory to
sev_unpin_memory() as a cleanup.
Reported-by: Cfir Cohen <cfir@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit cc5a726c ]

BITS_TO_LONGS() uses DIV_ROUND_UP() because of
this ppmax value can be greater than available
per cpu page pods.

This patch removes BITS_TO_LONGS() to fix this
issue.
Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 8601a99d ]

When enable SMMU, remove HNS driver will cause a WARNING:

[  141.924177] WARNING: CPU: 36 PID: 2708 at drivers/iommu/dma-iommu.c:443 __iommu_dma_unmap+0xc0/0xc8
[  141.954673] Modules linked in: hns_enet_drv(-)
[  141.963615] CPU: 36 PID: 2708 Comm: rmmod Tainted: G        W         5.0.0-rc1-28723-gb729c57de95c-dirty #32
[  141.983593] Hardware name: Huawei D05/D05, BIOS Hisilicon D05 UEFI Nemo 1.8 RC0 08/31/2017
[  142.000244] pstate: 60000005 (nZCv daif -PAN -UAO)
[  142.009886] pc : __iommu_dma_unmap+0xc0/0xc8
[  142.018476] lr : __iommu_dma_unmap+0xc0/0xc8
[  142.027066] sp : ffff000013533b90
[  142.033728] x29: ffff000013533b90 x28: ffff8013e6983600
[  142.044420] x27: 0000000000000000 x26: 0000000000000000
[  142.055113] x25: 0000000056000000 x24: 0000000000000015
[  142.065806] x23: 0000000000000028 x22: ffff8013e66eee68
[  142.076499] x21: ffff8013db919800 x20: 0000ffffefbff000
[  142.087192] x19: 0000000000001000 x18: 0000000000000007
[  142.097885] x17: 000000000000000e x16: 0000000000000001
[  142.108578] x15: 0000000000000019 x14: 363139343a70616d
[  142.119270] x13: 6e75656761705f67 x12: 0000000000000000
[  142.129963] x11: 00000000ffffffff x10: 0000000000000006
[  142.140656] x9 : 1346c1aa88093500 x8 : ffff0000114de4e0
[  142.151349] x7 : 6662666578303d72 x6 : ffff0000105ffec8
[  142.162042] x5 : 0000000000000000 x4 : 0000000000000000
[  142.172734] x3 : 00000000ffffffff x2 : ffff0000114de500
[  142.183427] x1 : 0000000000000000 x0 : 0000000000000035
[  142.194120] Call trace:
[  142.199030]  __iommu_dma_unmap+0xc0/0xc8
[  142.206920]  iommu_dma_unmap_page+0x20/0x28
[  142.215335]  __iommu_unmap_page+0x40/0x60
[  142.223399]  hnae_unmap_buffer+0x110/0x134
[  142.231639]  hnae_free_desc+0x6c/0x10c
[  142.239177]  hnae_fini_ring+0x14/0x34
[  142.246540]  hnae_fini_queue+0x2c/0x40
[  142.254080]  hnae_put_handle+0x38/0xcc
[  142.261619]  hns_nic_dev_remove+0x54/0xfc [hns_enet_drv]
[  142.272312]  platform_drv_remove+0x24/0x64
[  142.280552]  device_release_driver_internal+0x17c/0x20c
[  142.291070]  driver_detach+0x4c/0x90
[  142.298259]  bus_remove_driver+0x5c/0xd8
[  142.306148]  driver_unregister+0x2c/0x54
[  142.314037]  platform_driver_unregister+0x10/0x18
[  142.323505]  hns_nic_dev_driver_exit+0x14/0xf0c [hns_enet_drv]
[  142.335248]  __arm64_sys_delete_module+0x214/0x25c
[  142.344891]  el0_svc_common+0xb0/0x10c
[  142.352430]  el0_svc_handler+0x24/0x80
[  142.359968]  el0_svc+0x8/0x7c0
[  142.366104] ---[ end trace 60ad1cd58e63c407 ]---

The tx ring buffer map when xmit and unmap when xmit done. So in
hnae_init_ring() did not map tx ring buffer, but in hnae_fini_ring()
have a unmap operation for tx ring buffer, which is already unmapped
when xmit done, than cause this WARNING.

The hnae_alloc_buffers() is called in hnae_init_ring(),
so the hnae_free_buffers() should be in hnae_fini_ring(), not in
hnae_free_desc().

In hnae_fini_ring(), adds a check is_rx_ring() as in hnae_init_ring().
When the ring buffer is tx ring, adds a piece of code to ensure that
the tx ring is unmap.
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit f058e468 ]

ICMP6 neighbor solicitation messages will be discard by the Hip06
chips, because of not setting forwarding pool. Enable promisc mode
has the same problem.

This patch fix the wrong forwarding table configs for the multicast
vague matching when enable promisc mode, and add forwarding pool
for the forwarding table.
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit c0b09844 ]

When reboot the system again and again, may cause a memory
overwrite.

[   15.638922] systemd[1]: Reached target Swap.
[   15.667561] tun: Universal TUN/TAP device driver, 1.6
[   15.676756] Bridge firewalling registered
[   17.344135] Unable to handle kernel paging request at virtual address 0000000200000040
[   17.352179] Mem abort info:
[   17.355007]   ESR = 0x96000004
[   17.358105]   Exception class = DABT (current EL), IL = 32 bits
[   17.364112]   SET = 0, FnV = 0
[   17.367209]   EA = 0, S1PTW = 0
[   17.370393] Data abort info:
[   17.373315]   ISV = 0, ISS = 0x00000004
[   17.377206]   CM = 0, WnR = 0
[   17.380214] user pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____)
[   17.386926] [0000000200000040] pgd=0000000000000000
[   17.391878] Internal error: Oops: 96000004 [#1] SMP
[   17.396824] CPU: 23 PID: 95 Comm: kworker/u130:0 Tainted: G            E     4.19.25-1.2.78.aarch64 #1
[   17.414175] Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.54 08/16/2018
[   17.425615] Workqueue: events_unbound async_run_entry_fn
[   17.435151] pstate: 00000005 (nzcv daif -PAN -UAO)
[   17.444139] pc : __mutex_lock.isra.1+0x74/0x540
[   17.453002] lr : __mutex_lock.isra.1+0x3c/0x540
[   17.461701] sp : ffff000100d9bb60
[   17.469146] x29: ffff000100d9bb60 x28: 0000000000000000
[   17.478547] x27: 0000000000000000 x26: ffff802fb8945000
[   17.488063] x25: 0000000000000000 x24: ffff802fa32081a8
[   17.497381] x23: 0000000000000002 x22: ffff801fa2b15220
[   17.506701] x21: ffff000009809000 x20: ffff802fa23a0888
[   17.515980] x19: ffff801fa2b15220 x18: 0000000000000000
[   17.525272] x17: 0000000200000000 x16: 0000000200000000
[   17.534511] x15: 0000000000000000 x14: 0000000000000000
[   17.543652] x13: ffff000008d95db8 x12: 000000000000000d
[   17.552780] x11: ffff000008d95d90 x10: 0000000000000b00
[   17.561819] x9 : ffff000100d9bb90 x8 : ffff802fb89d6560
[   17.570829] x7 : 0000000000000004 x6 : 00000004a1801d05
[   17.579839] x5 : 0000000000000000 x4 : 0000000000000000
[   17.588852] x3 : ffff802fb89d5a00 x2 : 0000000000000000
[   17.597734] x1 : 0000000200000000 x0 : 0000000200000000
[   17.606631] Process kworker/u130:0 (pid: 95, stack limit = 0x(____ptrval____))
[   17.617438] Call trace:
[   17.623349]  __mutex_lock.isra.1+0x74/0x540
[   17.630927]  __mutex_lock_slowpath+0x24/0x30
[   17.638602]  mutex_lock+0x50/0x60
[   17.645295]  drain_workqueue+0x34/0x198
[   17.652623]  __sas_drain_work+0x7c/0x168
[   17.659903]  sas_drain_work+0x60/0x68
[   17.666947]  hisi_sas_scan_finished+0x30/0x40 [hisi_sas_main]
[   17.676129]  do_scsi_scan_host+0x70/0xb0
[   17.683534]  do_scan_async+0x20/0x228
[   17.690586]  async_run_entry_fn+0x4c/0x1d0
[   17.697997]  process_one_work+0x1b4/0x3f8
[   17.705296]  worker_thread+0x54/0x470

Every time the call trace is not the same, but the overwrite address
is always the same:
Unable to handle kernel paging request at virtual address 0000000200000040

The root cause is, when write the reg XGMAC_MAC_TX_LF_RF_CONTROL_REG,
didn't use the io_base offset.
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit acb1ce15 ]

When the HNS driver loaded, always have an error print:
"netif_napi_add() called with weight 256"

This is because the kernel checks the NAPI polling weights
requested by drivers and it prints an error message if a driver
requests a weight bigger than 64.

So use NAPI_POLL_WEIGHT to fix it.
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 3a39a12a ]

This patch is trying to fix the issue due to:
[27237.844750] BUG: KASAN: use-after-free in hns_nic_net_xmit_hw+0x708/0xa18[hns_enet_drv]

After hnae_queue_xmit() in hns_nic_net_xmit_hw(), can be
interrupted by interruptions, and than call hns_nic_tx_poll_one()
to handle the new packets, and free the skb. So, when turn back to
hns_nic_net_xmit_hw(), calling skb->len will cause use-after-free.

This patch update tx ring statistics in hns_nic_tx_poll_one() to
fix the bug.
Signed-off-by: Liubin Shu <shuliubin@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 1c418608 ]

When doing unwind_frame() in the context of pseudo nmi (need enable
CONFIG_ARM64_PSEUDO_NMI), reaching the bottom of the stack (fp == 0,
pc != 0), function on_sdei_stack() will return true while the sdei acpi
table is not inited in fact. This will cause a "NULL pointer dereference"
oops when going on.
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit ba5e60c9 ]

of_find_device_by_node() takes a reference to the struct device
when it finds a match via get_device. When returning error we should
call put_device.
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 382e06d1 ]

When the number of sub-channels offered by Hyper-V is >= the number of CPUs
in the VM, calculate the correct number of sub-channels.  The current code
produces one too many.

This scenario arises only when the number of CPUs is artificially
restricted (for example, with maxcpus=<n> on the kernel boot line), because
Hyper-V normally offers a sub-channel count < number of CPUs.  While the
current code doesn't break, the extra sub-channel is unbalanced across the
CPUs (for example, a total of 5 channels on a VM with 4 CPUs).
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 1cb1d2c6 ]

Blacklist "Universal Xport" LUN. It's used for in-band storage array
management.  Also add model to the rdac dh family.

Cc: Martin Wilck <mwilck@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: NetApp RDAC team <ng-eseries-upstream-maintainers@netapp.com>
Cc: Christophe Varoqui <christophe.varoqui@opensvc.com>
Cc: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: SCSI ML <linux-scsi@vger.kernel.org>
Cc: DM ML <dm-devel@redhat.com>
Signed-off-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 426b046b ]

When compiling with -Wformat, clang emits the following warnings:

drivers/vfio/pci/vfio_pci.c:1601:5: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                ^~~~~~

drivers/vfio/pci/vfio_pci.c:1601:13: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                        ^~~~~~

drivers/vfio/pci/vfio_pci.c:1601:21: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                                ^~~~~~~~~

drivers/vfio/pci/vfio_pci.c:1601:32: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                                           ^~~~~~~~~

drivers/vfio/pci/vfio_pci.c:1605:5: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                ^~~~~~

drivers/vfio/pci/vfio_pci.c:1605:13: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                        ^~~~~~

drivers/vfio/pci/vfio_pci.c:1605:21: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                                ^~~~~~~~~

drivers/vfio/pci/vfio_pci.c:1605:32: warning: format specifies type
      'unsigned short' but the argument has type 'unsigned int' [-Wformat]
                                vendor, device, subvendor, subdevice,
                                                           ^~~~~~~~~
The types of these arguments are unconditionally defined, so this patch
updates the format character to the correct ones for unsigned ints.

Link: https://github.com/ClangBuiltLinux/linux/issues/378Signed-off-by: Louis Taylor <louis@kragniz.eu>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit ce856634 ]

According to HUTRR89 usage 0x1cb from the consumer page was assigned to
allow launching desktop-aware assistant application, so let's add the
mapping.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 882c5e55 ]

The DA9063AD doesn't support alarms on any seconds and its granularity is
the minute. Set uie_unsupported in that case.
Reported-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit b9a1ff50 ]

kfree() can leak the hctx->fq->flush_rq field.
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 20bb907f ]

Since commit 6e2bd956936 ("i2c: omap: Use noirq system sleep pm ops to idle device for suspend")
on gta04 we have handle_twl4030_pih() called in situations where pm_runtime_get()
in i2c-omap.c returns -EACCES.

[   86.474365] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
[   86.485473] printk: Suspending console(s) (use no_console_suspend to debug)
[   86.555572] Disabling non-boot CPUs ...
[   86.555664] Successfully put all powerdomains to target state
[   86.563720] twl: Read failed (mod 1, reg 0x01 count 1)
[   86.563751] twl4030: I2C error -13 reading PIH ISR
[   86.563812] twl: Read failed (mod 1, reg 0x01 count 1)
[   86.563812] twl4030: I2C error -13 reading PIH ISR
[   86.563873] twl: Read failed (mod 1, reg 0x01 count 1)
[   86.563903] twl4030: I2C error -13 reading PIH ISR

This happens when we wakeup via something behing twl4030 (powerbutton or rtc
alarm). This goes on for minutes until the system is finally resumed.
Disable the irq on suspend and enable it on resume to avoid
having i2c access problems when the irq registers are checked.

Fixes: 6e2bd956936 ("i2c: omap: Use noirq system sleep pm ops to idle device for suspend")
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 93b919da ]

symlink body shouldn't be freed without an RCU delay.  Switch debugfs to
->destroy_inode() and use of call_rcu(); free both the inode and symlink
body in the callback.  Similar to solution for bpf, only here it's even
more obvious that ->evict_inode() can be dropped.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 4fdcfab5 ]

free the symlink body after the same RCU delay we have for freeing the
struct inode itself, so that traversal during RCU pathwalk wouldn't step
into freed memory.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 057a0c56 ]

This is log is harmful as it can trigger multiple times per packet. Delete
it.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 8ac0c24f ]

Packets without the last descriptor set should be dropped early. If we
receive a frame larger than the DMA buffer, the HW will continue using the
next descriptor. Driver mistakes these as individual frames, and sometimes
a truncated frame (without the LD set) may look like a valid packet.

This fixes a strange issue where the system replies to 4098-byte ping
although the MTU/DMA buffer size is set to 4096, and yet at the same
time it's logging an oversized packet.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 1b746ce8 ]

If we have error bits set, the discard_frame status will get overwritten
by checksum bit checks, which might set the status back to good one.
Fix by checking the COE status only if the frame is good.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 07b39753 ]

Currently, if we drop a packet, we exit from NAPI loop before the budget
is consumed. In some situations this will make the RX processing stall
e.g. when flood pinging the system with oversized packets, as the
errorneous packets are not dropped efficiently.

If we drop a packet, we should just continue to the next one as long as
the budget allows.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 972c9be7 ]

Ratelimit RX error logs.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 583e6361 ]

We always program the maximum DMA buffer size into the receive descriptor,
although the allocated size may be less. E.g. with the default MTU size
we allocate only 1536 bytes. If somebody sends us a bigger frame, then
memory may get corrupted.

Fix by using exact buffer sizes.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 18bebc6d ]

Bond expects ethernet hwaddr for its slave, but it can be longer than 6
bytes - infiniband interface for example.

 # cat /sys/devices/<skipped>/net/ib0/address
 80:00:02:08:fe:80:00:00:00:00:00:00:7c:fe:90:03:00:be:5d:e1

 # cat /sys/devices/<skipped>/net/ib0/bonding_slave/perm_hwaddr
 80:00:02:08:fe:80

So print full hwaddr in sysfs "bonding_slave/perm_hwaddr" as well.
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit eca4a928 ]

Traditionally, the PF (Physical Function) which resides on vport 0 was
the E-switch manager. Since the ECPF (Embedded CPU Physical Function),
which resides on vport 0xfffe, was introduced as the E-Switch manager,
the assumption that the E-switch manager is on vport 0 is incorrect.

Since the eswitch code already uses the actual vport value, all we
need is to always set other_vport=1.
Signed-off-by: Omri Kahalon <omrik@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 669efc76 ]

Currently, the rules for configuring search paths in Kbuild have
changed, this will lead some erros when compiling hns3 with the
following command:

make O=DIR M=drivers/net/ethernet/hisilicon/hns3

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_cmd.c:11:10:
fatal error: hnae3.h: No such file or directory

This patch fix it by adding $(srctree)/ prefix to the serach paths.
Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 2bafa1e9 ]

Similar to commit edfc3722 ("HID: quirks: Fix keyboard + touchpad on
Toshiba Click Mini not working"), the Lenovo Miix 630 has a combo
keyboard/touchpad device with vid:pid of 04F3:0400, which is shared with
Elan touchpads.  The combo on the Miix 630 has an ACPI id of QTEC0001,
which is not claimed by the elan_i2c driver, so key on that similar to
what was done for the Toshiba Click Mini.
Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit dbee9c9c ]

A memory save operation to 8-byte variable in RV32 is divided into
two sw instructions in the put_user macro.  The current fixup returns
execution flow to the second sw instead of the one after it.

This patch fixes this fixup code according to the load access part.

Signed-off-by: Alan Kao<alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit dabb8338 ]

The runtime_suspend device callbacks are not supposed to save
configuration state or change the power state. Commit fb29f76cc566
("igb: Fix an issue that PME is not enabled during runtime suspend")
changed the driver to not save configuration state during runtime
suspend, however the driver callback still put the device into a
low-power state. This causes a warning in the pci pm core and results in
pci_pm_runtime_suspend not calling pci_save_state or pci_finish_runtime_suspend.

Fix this by not changing the power state either, leaving that to pci pm
core, and make the same change for suspend callback as well.

Also move a couple of defines into the appropriate header file instead
of inline in the .c file.

Fixes: fb29f76cc566 ("igb: Fix an issue that PME is not enabled during runtime suspend")
Signed-off-by: Arvind Sankar <niveditas98@gmail.com>
Reviewed-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 13e8a05b ]

Set .owner to prevent module unloading while being used.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Fixes: d903779b ("reset: meson: add meson audio arb driver")
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit d040e4e8 ]

The device tree compiler yells like this:
  Warning (unit_address_vs_reg):
  /gpu-opp-table/opp@100000000:
  node has a unit name, but no reg property

Let's match the cpu opp node names and use a dash.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit ca8c3b92 ]

When CONFIG_CFG80211 isn't enabled the compiler correcly warns about
'sinfo.pertid' may be unused. It can also happen for other error
conditions that it not warn about.

net/batman-adv/bat_v_elp.c: In function ‘batadv_v_elp_get_throughput.isra.0’:
include/net/cfg80211.h:6370:13: warning: ‘sinfo.pertid’ may be used
 uninitialized in this function [-Wmaybe-uninitialized]
  kfree(sinfo->pertid);
        ~~~~~^~~~~~~~

Rework so that we only release '&sinfo' if cfg80211_get_station returns
zero.

Fixes: 7d652669 ("batman-adv: release station info tidstats")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit f131a568 ]

The batadv_hash_remove is a function which searches the hashtable for an
entry using a needle, a hashtable bucket selection function and a compare
function. It will lock the bucket list and delete an entry when the compare
function matches it with the needle. It returns the pointer to the
hlist_node which matches or NULL when no entry matches the needle.

The batadv_tt_global_free is not itself protected in anyway to avoid that
any other function is modifying the hashtable between the search for the
entry and the call to batadv_hash_remove. It can therefore happen that the
entry either doesn't exist anymore or an entry was deleted which is not the
same object as the needle. In such an situation, the reference counter (for
the reference stored in the hashtable) must not be reduced for the needle.
Instead the reference counter of the actually removed entry has to be
reduced.

Otherwise the reference counter will underflow and the object might be
freed before all its references were dropped. The kref helpers reported
this problem as:

  refcount_t: underflow; use-after-free.

Fixes: 7683fdc1 ("batman-adv: protect the local and the global trans-tables with rcu")
Reported-by: Martin Weinelt <martin@linuxlounge.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>