x86/pti/32: Calculate the various PTI cpu_entry_area sizes correctly, make the CPU_ENTRY_AREA_PAGES assert precise

When two recent commits that increased the size of the 'struct cpu_entry_area'
were merged in -tip, the 32-bit defconfig build started failing on the following
build time assert:

  ./include/linux/compiler.h:391:38: error: call to ‘__compiletime_assert_189’ declared with attribute error: BUILD_BUG_ON failed: CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE
  arch/x86/mm/cpu_entry_area.c:189:2: note: in expansion of macro ‘BUILD_BUG_ON’
  In function ‘setup_cpu_entry_area_ptes’,

Which corresponds to the following build time assert:

	BUILD_BUG_ON(CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE);

The purpose of this assert is to sanity check the fixed-value definition of
CPU_ENTRY_AREA_PAGES arch/x86/include/asm/pgtable_32_types.h:

	#define CPU_ENTRY_AREA_PAGES    (NR_CPUS * 41)

The '41' is supposed to match sizeof(struct cpu_entry_area)/PAGE_SIZE, which value
we didn't want to define in such a low level header, because it would cause
dependency hell.

Every time the size of cpu_entry_area is changed, we have to adjust CPU_ENTRY_AREA_PAGES
accordingly - and this assert is checking that constraint.

But the assert is both imprecise and buggy, primarily because it doesn't
include the single readonly IDT page that is mapped at CPU_ENTRY_AREA_BASE
(which begins at a PMD boundary).

This bug was hidden by the fact that by accident CPU_ENTRY_AREA_PAGES is defined
too large upstream (v5.4-rc8):

	#define CPU_ENTRY_AREA_PAGES    (NR_CPUS * 40)

While 'struct cpu_entry_area' is 155648 bytes, or 38 pages. So we had two extra
pages, which hid the bug.

The following commit (not yet upstream) increased the size to 40 pages:

  x86/iopl: ("Restrict iopl() permission scope")

... but increased CPU_ENTRY_AREA_PAGES only 41 - i.e. shortening the gap
to just 1 extra page.

Then another not-yet-upstream commit changed the size again:

  880a98c3: ("x86/cpu_entry_area: Add guard page for entry stack on 32bit")

Which increased the cpu_entry_area size from 38 to 39 pages, but
didn't change CPU_ENTRY_AREA_PAGES (kept it at 40). This worked
fine, because we still had a page left from the accidental 'reserve'.

But when these two commits were merged into the same tree, the
combined size of cpu_entry_area grew from 38 to 40 pages, while
CPU_ENTRY_AREA_PAGES finally caught up to 40 as well.

Which is fine in terms of functionality, but the assert broke:

	BUILD_BUG_ON(CPU_ENTRY_AREA_PAGES * PAGE_SIZE < CPU_ENTRY_AREA_MAP_SIZE);

because CPU_ENTRY_AREA_MAP_SIZE is the total size of the area,
which is 1 page larger due to the IDT page.

To fix all this, change the assert to two precise asserts:

	BUILD_BUG_ON((CPU_ENTRY_AREA_PAGES+1)*PAGE_SIZE != CPU_ENTRY_AREA_MAP_SIZE);
	BUILD_BUG_ON(CPU_ENTRY_AREA_TOTAL_SIZE != CPU_ENTRY_AREA_MAP_SIZE);

This takes the IDT page into account, and also connects the size-based
define of CPU_ENTRY_AREA_TOTAL_SIZE with the address-subtraction based
define of CPU_ENTRY_AREA_MAP_SIZE.

Also clean up some of the names which made it rather confusing:

 - 'CPU_ENTRY_AREA_TOT_SIZE' wasn't actually the 'total' size of
   the cpu-entry-area, but the per-cpu array size, so rename this
   to CPU_ENTRY_AREA_ARRAY_SIZE.

 - Introduce CPU_ENTRY_AREA_TOTAL_SIZE that _is_ the total mapping
   size, with the IDT included.

 - Add comments where '+1' denotes the IDT mapping - it wasn't
   obvious and took me about 3 hours to decode...

Finally, because this particular commit is actually applied after
this patch:

  880a98c3: ("x86/cpu_entry_area: Add guard page for entry stack on 32bit")

Fix the CPU_ENTRY_AREA_PAGES value from 40 pages to the correct 39 pages.

All future commits that change cpu_entry_area will have to adjust
this value precisely.

As a side note, we should probably attempt to remove CPU_ENTRY_AREA_PAGES
and derive its value directly from the structure, without causing
header hell - but that is an adventure for another day! :-)

Fixes: 880a98c3: ("x86/cpu_entry_area: Add guard page for entry stack on 32bit")
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

If the kernel accidentally uses DS or ES while the user values are
loaded, it will work fine for sane userspace.  In the interest of
simulating maximally insane userspace, make sigreturn_32 zero out DS
and ES for the nasty parts so that inadvertent use of these segments
will crash.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

For reasons that I haven't quite fully diagnosed, running
mov_ss_trap_32 on a 32-bit kernel results in an infinite loop in
userspace.  This appears to be because the hacky SYSENTER test
doesn't segfault as desired; instead it corrupts the program state
such that it infinite loops.

Fix it by explicitly clearing EBP before doing SYSENTER.  This will
give a more reliable segfault.

Fixes: 59c2a722 ("x86/selftests: Add mov_to_ss test")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

When the NMI lands on an ESPFIX_SS, we are on the entry stack and must
swizzle, otherwise we'll run do_nmi() on the entry stack, which is
BAD.

Also, similar to the normal exception path, we need to correct the
ESPFIX magic before leaving the entry stack, otherwise pt_regs will
present a non-flat stack pointer.

Tested by running sigreturn_32 concurrent with perf-record.

Fixes: e5862d05 ("x86/entry/32: Leave the kernel via trampoline stack")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org

Right now, we do some fancy parts of the exception entry path while SS
might have a nonzero base: we fill in regs->ss and regs->sp, and we
consider switching to the kernel stack. This results in regs->ss and
regs->sp referring to a non-flat stack and it may result in
overflowing the entry stack. The former issue means that we can try to
call iret_exc on a non-flat stack, which doesn't work.

Tested with selftests/x86/sigreturn_32.

Fixes: 45d7b255 ("x86/entry/32: Enter the kernel via trampoline stack")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

This will allow us to get percpu access working before FIXUP_FRAME,
which will allow us to unwind ESPFIX earlier.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

When re-building the IRET frame we use %eax as an destination %esp,
make sure to then also match the segment for when there is a nonzero
SS base (ESPFIX).

[peterz: Changelog and minor edits]
Fixes: 3c88c692 ("x86/stackframe/32: Provide consistent pt_regs")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

As reported by Lai, the commit 3c88c692 ("x86/stackframe/32:
Provide consistent pt_regs") wrecked the IRET EXTABLE entry by making
.Lirq_return not point at IRET.

Fix this by placing IRET_FRAME in RESTORE_REGS, to mirror how
FIXUP_FRAME is part of SAVE_ALL.

Fixes: 3c88c692 ("x86/stackframe/32: Provide consistent pt_regs")
Reported-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org

The entry stack in the cpu entry area is protected against overflow by the
readonly GDT on 64-bit, but on 32-bit the GDT needs to be writeable and
therefore does not trigger a fault on stack overflow.

Add a guard page.

Fixes: c482feef ("x86/entry/64: Make cpu_entry_area.tss read-only")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

Commit 945fd17a ("x86/cpu_entry_area: Sync cpu_entry_area to
initial_page_table") introduced the sync for the initial page table for
32bit.

sync_initial_page_table() uses clone_pgd_range() which does the update for
the kernel page table. If PTI is enabled it also updates the user space
page table counterpart, which is assumed to be in the next page after the
target PGD.

At this point in time 32-bit did not have PTI support, so the user space
page table update was not taking place.

The support for PTI on 32-bit which was introduced later on, did not take
that into account and missed to add the user space counter part for the
initial page table.

As a consequence sync_initial_page_table() overwrites any data which is
located in the page behing initial_page_table causing random failures,
e.g. by corrupting doublefault_tss and wreckaging the doublefault handler
on 32bit.

Fix it by adding a "user" page table right after initial_page_table.

Fixes: 7757d607 ("x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Cc: stable@kernel.org

The double fault TSS was missing GS setup, which is needed for stack
canaries to work.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@kernel.org

This can be had with two instead of six insns, by just checking the high
CS.RPL bit.

Also adjust the comment - there would be no #GP in the mentioned cases, as
there's no segment limit violation or alike. Instead there'd be #PF, but
that one reports the target EIP of said branch, not the address of the
branch insn itself.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/a5986837-01eb-7bf8-bf42-4d3084d6a1f5@suse.com

Now that SS:ESP always get saved by SAVE_ALL, this also needs to be
accounted for in xen_iret_crit_fixup(). Otherwise the old_ax value gets
interpreted as EFLAGS, and hence VM86 mode appears to be active all the
time, leading to random "vm86_32: no user_vm86: BAD" log messages alongside
processes randomly crashing.

Since following the previous model (sitting after SAVE_ALL) would further
complicate the code _and_ retain the dependency of xen_iret_crit_fixup() on
frame manipulations done by entry_32.S, switch things around and do the
adjustment ahead of SAVE_ALL.

Fixes: 3c88c692 ("x86/stackframe/32: Provide consistent pt_regs")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Stable Team <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/32d8713d-25a7-84ab-b74b-aa3e88abce6b@suse.com

Once again RPL checks have been introduced which don't account for a 32-bit
kernel living in ring 1 when running in a PV Xen domain. The case in
FIXUP_FRAME has been preventing boot.

Adjust BUG_IF_WRONG_CR3 as well to guard against future uses of the macro
on a code path reachable when running in PV mode under Xen; I have to admit
that I stopped at a certain point trying to figure out whether there are
present ones.

Fixes: 3c88c692 ("x86/stackframe/32: Provide consistent pt_regs")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stable Team <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/0fad341f-b7f5-f859-d55d-f0084ee7087e@suse.com

Pull iommu fixes from Joerg Roedel:

 - Fix for Intel IOMMU to correct invalidation commands when in SVA
   mode.

 - Update MAINTAINERS entry for Intel IOMMU

* tag 'iommu-fixes-v5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/vt-d: Fix QI_DEV_IOTLB_PFSID and QI_DEV_EIOTLB_PFSID macros
  MAINTAINERS: Update for INTEL IOMMU (VT-d) entry

Pull misc scheduler fixes from Ingo Molnar:

 - Fix potential deadlock under CONFIG_DEBUG_OBJECTS=y

 - PELT metrics update ordering fix

 - uclamp logic fix

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/uclamp: Fix incorrect condition
  sched/pelt: Fix update of blocked PELT ordering
  sched/core: Avoid spurious lock dependencies

Pull i2c fixes from Wolfram Sang:
 "An I2C core fix to prevent a use-after-free in a rare error path,
  and an I2C ACPI addition to work around broken HW/firmware related
  to touchscreens"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: core: fix use after free in of_i2c_notify
  i2c: acpi: Force bus speed to 400KHz if a Silead touchscreen is present

Pull crypto fix from Herbert Xu:
 "This reverts a number of changes to the khwrng thread which feeds the
  kernel random number pool from hwrng drivers. They were trying to fix
  issues with suspend-and-resume but ended up causing regressions"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  Revert "hwrng: core - Freeze khwrng thread during suspend"

This reverts commit 03a3bb7a ("hwrng: core - Freeze khwrng
thread during suspend"), ff296293 ("random: Support freezable
kthreads in add_hwgenerator_randomness()") and 59b56948 ("random:
Use wait_event_freezable() in add_hwgenerator_randomness()").

These patches introduced regressions and we need more time to
get them ready for mainline.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Pull x86 fixes from Ingo Molnar:
 "Two fixes: disable unreliable HPET on Intel Coffe Lake platforms, and
  fix a lockdep splat in the resctrl code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Fix potential lockdep warning
  x86/quirks: Disable HPET on Intel Coffe Lake platforms

Pull timer fix from Ingo Molnar:
 "Fix integer truncation bug in __do_adjtimex()"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ntp/y2038: Remove incorrect time_t truncation

Pull perf fixes from Ingo Molnar:
 "Misc fixes: a handful of AUX event handling related fixes, a Sparse
  fix and two ABI fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix missing static inline on perf_cgroup_switch()
  perf/core: Consistently fail fork on allocation failures
  perf/aux: Disallow aux_output for kernel events
  perf/core: Reattach a misplaced comment
  perf/aux: Fix the aux_output group inheritance fix
  perf/core: Disallow uncore-cgroup events

Pull networking fixes from David Miller:

 1) Fix memory leak in xfrm_state code, from Steffen Klassert.

 2) Fix races between devlink reload operations and device
    setup/cleanup, from Jiri Pirko.

 3) Null deref in NFC code, from Stephan Gerhold.

 4) Refcount fixes in SMC, from Ursula Braun.

 5) Memory leak in slcan open error paths, from Jouni Hogander.

 6) Fix ETS bandwidth validation in hns3, from Yonglong Liu.

 7) Info leak on short USB request answers in ax88172a driver, from
    Oliver Neukum.

 8) Release mem region properly in ep93xx_eth, from Chuhong Yuan.

 9) PTP config timestamp flags validation, from Richard Cochran.

10) Dangling pointers after SKB data realloc in seg6, from Andrea Mayer.

11) Missing free_netdev() in gemini driver, from Chuhong Yuan.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (56 commits)
  ipmr: Fix skb headroom in ipmr_get_route().
  net: hns3: cleanup of stray struct hns3_link_mode_mapping
  net/smc: fix fastopen for non-blocking connect()
  rds: ib: update WR sizes when bringing up connection
  net: gemini: add missed free_netdev
  net: dsa: tag_8021q: Fix dsa_8021q_restore_pvid for an absent pvid
  seg6: fix skb transport_header after decap_and_validate()
  seg6: fix srh pointer in get_srh()
  net: stmmac: Use the correct style for SPDX License Identifier
  octeontx2-af: Use the correct style for SPDX License Identifier
  ptp: Extend the test program to check the external time stamp flags.
  mlx5: Reject requests to enable time stamping on both edges.
  igb: Reject requests that fail to enable time stamping on both edges.
  dp83640: Reject requests to enable time stamping on both edges.
  mv88e6xxx: Reject requests to enable time stamping on both edges.
  ptp: Introduce strict checking of external time stamp options.
  renesas: reject unsupported external timestamp flags
  mlx5: reject unsupported external timestamp flags
  igb: reject unsupported external timestamp flags
  dp83640: reject unsupported external timestamp flags
  ...

In route.c, inet_rtm_getroute_build_skb() creates an skb with no
headroom. This skb is then used by inet_rtm_getroute() which may pass
it to rt_fill_info() and, from there, to ipmr_get_route(). The later
might try to reuse this skb by cloning it and prepending an IPv4
header. But since the original skb has no headroom, skb_push() triggers
skb_under_panic():

skbuff: skb_under_panic: text:00000000ca46ad8a len:80 put:20 head:00000000cd28494e data:000000009366fd6b tail:0x3c end:0xec0 dev:veth0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:108!
invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 6 PID: 587 Comm: ip Not tainted 5.4.0-rc6+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
RIP: 0010:skb_panic+0xbf/0xd0
Code: 41 a2 ff 8b 4b 70 4c 8b 4d d0 48 c7 c7 20 76 f5 8b 44 8b 45 bc 48 8b 55 c0 48 8b 75 c8 41 54 41 57 41 56 41 55 e8 75 dc 7a ff <0f> 0b 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00
RSP: 0018:ffff888059ddf0b0 EFLAGS: 00010286
RAX: 0000000000000086 RBX: ffff888060a315c0 RCX: ffffffff8abe4822
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88806c9a79cc
RBP: ffff888059ddf118 R08: ffffed100d9361b1 R09: ffffed100d9361b0
R10: ffff88805c68aee3 R11: ffffed100d9361b1 R12: ffff88805d218000
R13: ffff88805c689fec R14: 000000000000003c R15: 0000000000000ec0
FS:  00007f6af184b700(0000) GS:ffff88806c980000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc8204a000 CR3: 0000000057b40006 CR4: 0000000000360ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_push+0x7e/0x80
 ipmr_get_route+0x459/0x6fa
 rt_fill_info+0x692/0x9f0
 inet_rtm_getroute+0xd26/0xf20
 rtnetlink_rcv_msg+0x45d/0x630
 netlink_rcv_skb+0x1a5/0x220
 rtnetlink_rcv+0x15/0x20
 netlink_unicast+0x305/0x3a0
 netlink_sendmsg+0x575/0x730
 sock_sendmsg+0xb5/0xc0
 ___sys_sendmsg+0x497/0x4f0
 __sys_sendmsg+0xcb/0x150
 __x64_sys_sendmsg+0x48/0x50
 do_syscall_64+0xd2/0xac0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Actually the original skb used to have enough headroom, but the
reserve_skb() call was lost with the introduction of
inet_rtm_getroute_build_skb() by commit 404eb77e ("ipv4: support
sport, dport and ip_proto in RTM_GETROUTE").

We could reserve some headroom again in inet_rtm_getroute_build_skb(),
but this function shouldn't be responsible for handling the special
case of ipmr_get_route(). Let's handle that directly in
ipmr_get_route() by calling skb_realloc_headroom() instead of
skb_clone().

Fixes: 404eb77e ("ipv4: support sport, dport and ip_proto in RTM_GETROUTE")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch cleans-up the stray left over code. It has no
functionality impact.
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

FASTOPEN does not work with SMC-sockets. Since SMC allows fallback to
TCP native during connection start, the FASTOPEN setsockopts trigger
this fallback, if the SMC-socket is still in state SMC_INIT.
But if a FASTOPEN setsockopt is called after a non-blocking connect(),
this is broken, and fallback does not make sense.
This change complements
commit cd206360 ("net/smc: avoid fallback in case of non-blocking connect")
and fixes the syzbot reported problem "WARNING in smc_unhash_sk".

Reported-by: syzbot+8488cc4cf1c9e09b8b86@syzkaller.appspotmail.com
Fixes: e1bbdd57 ("net/smc: reduce sock_put() for fallback sockets")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently WR sizes are updated from rds_ib_sysctl_max_send_wr and
rds_ib_sysctl_max_recv_wr when a connection is shut down. As a result,
a connection being down while rds_ib_sysctl_max_send_wr or
rds_ib_sysctl_max_recv_wr are updated, will not update the sizes when
it comes back up.

Move resizing of WRs to rds_ib_setup_qp so that connections will be setup
with the most current WR sizes.
Signed-off-by: Dag Moxnes <dag.moxnes@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This driver forgets to free allocated netdev in remove like
what is done in probe failure.
Add the free to fix it.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

This sequence of operations:
ip link set dev br0 type bridge vlan_filtering 1
bridge vlan del dev swp2 vid 1
ip link set dev br0 type bridge vlan_filtering 1
ip link set dev br0 type bridge vlan_filtering 0

apparently fails with the message:

[   31.305716] sja1105 spi0.1: Reset switch and programmed static config. Reason: VLAN filtering
[   31.322161] sja1105 spi0.1: Couldn't determine PVID attributes (pvid 0)
[   31.328939] sja1105 spi0.1: Failed to setup VLAN tagging for port 1: -2
[   31.335599] ------------[ cut here ]------------
[   31.340215] WARNING: CPU: 1 PID: 194 at net/switchdev/switchdev.c:157 switchdev_port_attr_set_now+0x9c/0xa4
[   31.349981] br0: Commit of attribute (id=6) failed.
[   31.354890] Modules linked in:
[   31.357942] CPU: 1 PID: 194 Comm: ip Not tainted 5.4.0-rc6-01792-gf4f632e07665-dirty #2062
[   31.366167] Hardware name: Freescale LS1021A
[   31.370437] [<c03144dc>] (unwind_backtrace) from [<c030e184>] (show_stack+0x10/0x14)
[   31.378153] [<c030e184>] (show_stack) from [<c11d1c1c>] (dump_stack+0xe0/0x10c)
[   31.385437] [<c11d1c1c>] (dump_stack) from [<c034c730>] (__warn+0xf4/0x10c)
[   31.392373] [<c034c730>] (__warn) from [<c034c7bc>] (warn_slowpath_fmt+0x74/0xb8)
[   31.399827] [<c034c7bc>] (warn_slowpath_fmt) from [<c11ca204>] (switchdev_port_attr_set_now+0x9c/0xa4)
[   31.409097] [<c11ca204>] (switchdev_port_attr_set_now) from [<c117036c>] (__br_vlan_filter_toggle+0x6c/0x118)
[   31.418971] [<c117036c>] (__br_vlan_filter_toggle) from [<c115d010>] (br_changelink+0xf8/0x518)
[   31.427637] [<c115d010>] (br_changelink) from [<c0f8e9ec>] (__rtnl_newlink+0x3f4/0x76c)
[   31.435613] [<c0f8e9ec>] (__rtnl_newlink) from [<c0f8eda8>] (rtnl_newlink+0x44/0x60)
[   31.443329] [<c0f8eda8>] (rtnl_newlink) from [<c0f89f20>] (rtnetlink_rcv_msg+0x2cc/0x51c)
[   31.451477] [<c0f89f20>] (rtnetlink_rcv_msg) from [<c1008df8>] (netlink_rcv_skb+0xb8/0x110)
[   31.459796] [<c1008df8>] (netlink_rcv_skb) from [<c1008648>] (netlink_unicast+0x17c/0x1f8)
[   31.468026] [<c1008648>] (netlink_unicast) from [<c1008980>] (netlink_sendmsg+0x2bc/0x3b4)
[   31.476261] [<c1008980>] (netlink_sendmsg) from [<c0f43858>] (___sys_sendmsg+0x230/0x250)
[   31.484408] [<c0f43858>] (___sys_sendmsg) from [<c0f44c84>] (__sys_sendmsg+0x50/0x8c)
[   31.492209] [<c0f44c84>] (__sys_sendmsg) from [<c0301000>] (ret_fast_syscall+0x0/0x28)
[   31.500090] Exception stack(0xedf47fa8 to 0xedf47ff0)
[   31.505122] 7fa0:                   00000002 b6f2e060 00000003 beabd6a4 00000000 00000000
[   31.513265] 7fc0: 00000002 b6f2e060 5d6e3213 00000128 00000000 00000001 00000006 000619c4
[   31.521405] 7fe0: 00086078 beabd658 0005edbc b6e7ce68

The reason is the implementation of br_get_pvid:

static inline u16 br_get_pvid(const struct net_bridge_vlan_group *vg)
{
	if (!vg)
		return 0;

	smp_rmb();
	return vg->pvid;
}

Since VID 0 is an invalid pvid from the bridge's point of view, let's
add this check in dsa_8021q_restore_pvid to avoid restoring a pvid that
doesn't really exist.

Fixes: 5f33183b ("net: dsa: tag_8021q: Restore bridge VLANs when enabling vlan_filtering")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Andrea Mayer says:

====================
seg6: fixes to Segment Routing in IPv6

This patchset is divided in 2 patches and it introduces some fixes
to Segment Routing in IPv6, which are:

- in function get_srh() fix the srh pointer after calling
  pskb_may_pull();

- fix the skb->transport_header after calling decap_and_validate()
  function;

Any comments on the patchset are welcome.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

in the receive path (more precisely in ip6_rcv_core()) the
skb->transport_header is set to skb->network_header + sizeof(*hdr). As a
consequence, after routing operations, destination input expects to find
skb->transport_header correctly set to the next protocol (or extension
header) that follows the network protocol. However, decap behaviors (DX*,
DT*) remove the outer IPv6 and SRH extension and do not set again the
skb->transport_header pointer correctly. For this reason, the patch sets
the skb->transport_header to the skb->network_header + sizeof(hdr) in each
DX* and DT* behavior.
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Signed-off-by: David S. Miller <davem@davemloft.net>

pskb_may_pull may change pointers in header. For this reason, it is
mandatory to reload any pointer that points into skb header.
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch corrects the SPDX License Identifier style in
header files related to STMicroelectronics based Multi-Gigabit
Ethernet driver. For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch corrects the SPDX License Identifier style in
header files related to Marvell OcteonTX2 network devices.
It uses an expilict block comment for the SPDX License
Identifier.

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge misc fixes from Andrew Morton:
 "11 fixes"

MM fixes and one xz decompressor fix.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/debug.c: PageAnon() is true for PageKsm() pages
  mm/debug.c: __dump_page() prints an extra line
  mm/page_io.c: do not free shared swap slots
  mm/memory_hotplug: fix try_offline_node()
  mm,thp: recheck each page before collapsing file THP
  mm: slub: really fix slab walking for init_on_free
  mm: hugetlb: switch to css_tryget() in hugetlb_cgroup_charge_cgroup()
  mm: memcg: switch to css_tryget() in get_mem_cgroup_from_mm()
  lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocations
  mm: fix trying to reclaim unevictable lru page when calling madvise_pageout
  mm: mempolicy: fix the wrong return value and potential pages leak of mbind

Pull more input fixes from Dmitry Torokhov:
 "A couple of fixes in driver teardown paths and another ID for
  Synaptics RMI mode"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: synaptics - enable RMI mode for X1 Extreme 2nd Generation
  Input: synaptics-rmi4 - destroy F54 poller workqueue when removing
  Input: ff-memless - kill timer in destroy()

PageAnon() and PageKsm() use the low two bits of the page->mapping
pointer to indicate the page type.  PageAnon() only checks the LSB while
PageKsm() checks the least significant 2 bits are equal to 3.

Therefore, PageAnon() is true for KSM pages.  __dump_page() incorrectly
will never print "ksm" because it checks PageAnon() first.  Fix this by
checking PageKsm() first.

Link: http://lkml.kernel.org/r/20191113000651.20677-1-rcampbell@nvidia.com
Fixes: 1c6fb1d8 ("mm: print more information about mapping in __dump_page")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When dumping struct page information, __dump_page() prints the page type
with a trailing blank followed by the page flags on a separate line:

  anon
  flags: 0x100000000090034(uptodate|lru|active|head|swapbacked)

It looks like the intent was to use pr_cont() for printing "flags:" but
pr_cont() usage is discouraged so fix this by extending the format to
include the flags into a single line:

  anon flags: 0x100000000090034(uptodate|lru|active|head|swapbacked)

If the page is file backed, the name might be long so use two lines:

  shmem_aops name:"dev/zero"
  flags: 0x10000000008000c(uptodate|dirty|swapbacked)

Eliminate pr_conf() usage as well for appending compound_mapcount.

Link: http://lkml.kernel.org/r/20191112012608.16926-1-rcampbell@nvidia.comSigned-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The following race is observed due to which a processes faulting on a
swap entry, finds the page neither in swapcache nor swap.  This causes
zram to give a zero filled page that gets mapped to the process,
resulting in a user space crash later.

Consider parent and child processes Pa and Pb sharing the same swap slot
with swap_count 2.  Swap is on zram with SWP_SYNCHRONOUS_IO set.
Virtual address 'VA' of Pa and Pb points to the shared swap entry.

Pa                                       Pb

fault on VA                              fault on VA
do_swap_page                             do_swap_page
lookup_swap_cache fails                  lookup_swap_cache fails
                                         Pb scheduled out
swapin_readahead (deletes zram entry)
swap_free (makes swap_count 1)
                                         Pb scheduled in
                                         swap_readpage (swap_count == 1)
                                         Takes SWP_SYNCHRONOUS_IO path
                                         zram enrty absent
                                         zram gives a zero filled page

Fix this by making sure that swap slot is freed only when swap count
drops down to one.

Link: http://lkml.kernel.org/r/1571743294-14285-1-git-send-email-vinmenon@codeaurora.org
Fixes: aa8d22a1 ("mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference")
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Suggested-by: Minchan Kim <minchan@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>