linux.git, branch v5.4.56

Linux 5.4.56

2020-08-05T07:59:52+00:00

Tested-by: Shuah Khan 
Signed-off-by: Greg Kroah-Hartman

perf bench: Share some global variables to fix build with gcc 10

2020-08-05T07:59:52+00:00

commit e4d9b04b973b2dbce7b42af95ea70d07da1c936d upstream.

Noticed with gcc 10 (fedora rawhide) that those variables were not being
declared as static, so end up with:

  ld: /tmp/build/perf/bench/epoll-wait.o:/git/perf/tools/perf/bench/epoll-wait.c:93: multiple definition of `end'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-wait.o:/git/perf/tools/perf/bench/epoll-wait.c:93: multiple definition of `start'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-wait.o:/git/perf/tools/perf/bench/epoll-wait.c:93: multiple definition of `runtime'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-ctl.o:/git/perf/tools/perf/bench/epoll-ctl.c:38: multiple definition of `end'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-ctl.o:/git/perf/tools/perf/bench/epoll-ctl.c:38: multiple definition of `start'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-ctl.o:/git/perf/tools/perf/bench/epoll-ctl.c:38: multiple definition of `runtime'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  make[4]: *** [/git/perf/tools/build/Makefile.build:145: /tmp/build/perf/bench/perf-in.o] Error 1

Prefix those with bench__ and add them to bench/bench.h, so that we can
share those on the tools needing to access those variables from signal
handlers.

Acked-by: Thomas Gleixner 
Cc: Adrian Hunter 
Cc: Davidlohr Bueso 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: http://lore.kernel.org/lkml/20200303155811.GD13702@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

perf env: Do not return pointers to local variables

2020-08-05T07:59:52+00:00

commit ebcb9464a2ae3a547e97de476575c82ece0e93e2 upstream.

It is possible to return a pointer to a local variable when looking up
the architecture name for the running system and no normalization is
done on that value, i.e. we may end up returning the uts.machine local
variable.

While this doesn't happen on most arches, as normalization takes place,
lets fix this by making that a static variable and optimize it a bit by
not always running uname(), only the first time.

Noticed in fedora rawhide running with:

  [perfbuilder@a5ff49d6e6e4 ~]$ gcc --version
  gcc (GCC) 10.0.1 20200216 (Red Hat 10.0.1-0.8)

Reported-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

perf tests bp_account: Make global variable static

2020-08-05T07:59:52+00:00

commit cff20b3151ccab690715cb6cf0f5da5cccb32adf upstream.

To fix the build with newer gccs, that without this patch exit with:

    LD       /tmp/build/perf/tests/perf-in.o
  ld: /tmp/build/perf/tests/bp_account.o:/git/perf/tools/perf/tests/bp_account.c:22: multiple definition of `the_var'; /tmp/build/perf/tests/bp_signal.o:/git/perf/tools/perf/tests/bp_signal.c:38: first defined here
  make[4]: *** [/git/perf/tools/build/Makefile.build:145: /tmp/build/perf/tests/perf-in.o] Error 1

First noticed in fedora:rawhide/32 with:

  [perfbuilder@a5ff49d6e6e4 ~]$ gcc --version
  gcc (GCC) 10.0.1 20200216 (Red Hat 10.0.1-0.8)

Reported-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

x86/i8259: Use printk_deferred() to prevent deadlock

2020-08-05T07:59:52+00:00

commit bdd65589593edd79b6a12ce86b3b7a7c6dae5208 upstream.

0day reported a possible circular locking dependency:

Chain exists of:
  &irq_desc_lock_class --> console_owner --> &port_lock_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&port_lock_key);
                               lock(console_owner);
                               lock(&port_lock_key);
  lock(&irq_desc_lock_class);

The reason for this is a printk() in the i8259 interrupt chip driver
which is invoked with the irq descriptor lock held, which reverses the
lock operations vs. printk() from arbitrary contexts.

Switch the printk() to printk_deferred() to avoid that.

Reported-by: kernel test robot 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87365abt2v.fsf@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman

KVM: LAPIC: Prevent setting the tscdeadline timer if the lapic is hw disabled

2020-08-05T07:59:52+00:00

commit d2286ba7d574ba3103a421a2f9ec17cb5b0d87a1 upstream.

Prevent setting the tscdeadline timer if the lapic is hw disabled.

Fixes: bce87cce88 (KVM: x86: consolidate different ways to test for in-kernel LAPIC)
Cc: 
Signed-off-by: Wanpeng Li 
Message-Id: <1596165141-28874-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Don't inherit exec permission across page-table levels

2020-08-05T07:59:51+00:00

commit b757b47a2fcba584d4a32fd7ee68faca510ab96f upstream.

If a stage-2 page-table contains an executable, read-only mapping at the
pte level (e.g. due to dirty logging being enabled), a subsequent write
fault to the same page which tries to install a larger block mapping
(e.g. due to dirty logging having been disabled) will erroneously inherit
the exec permission and consequently skip I-cache invalidation for the
rest of the block.

Ensure that exec permission is only inherited by write faults when the
new mapping is of the same size as the existing one. A subsequent
instruction abort will result in I-cache invalidation for the entire
block mapping.

Signed-off-by: Will Deacon 
Signed-off-by: Marc Zyngier 
Tested-by: Quentin Perret 
Reviewed-by: Quentin Perret 
Cc: Marc Zyngier 
Cc: 
Link: https://lore.kernel.org/r/20200723101714.15873-1-will@kernel.org
Signed-off-by: Greg Kroah-Hartman

drivers/net/wan: lapb: Corrected the usage of skb_cow

2020-08-05T07:59:51+00:00

[ Upstream commit 8754e1379e7089516a449821f88e1fe1ebbae5e1 ]

This patch fixed 2 issues with the usage of skb_cow in LAPB drivers
"lapbether" and "hdlc_x25":

1) After skb_cow fails, kfree_skb should be called to drop a reference
to the skb. But in both drivers, kfree_skb is not called.

2) skb_cow should be called before skb_push so that is can ensure the
safety of skb_push. But in "lapbether", it is incorrectly called after
skb_push.

More details about these 2 issues:

1) The behavior of calling kfree_skb on failure is also the behavior of
netif_rx, which is called by this function with "return netif_rx(skb);".
So this function should follow this behavior, too.

2) In "lapbether", skb_cow is called after skb_push. This results in 2
logical issues:
   a) skb_push is not protected by skb_cow;
   b) An extra headroom of 1 byte is ensured after skb_push. This extra
      headroom has no use in this function. It also has no use in the
      upper-layer function that this function passes the skb to
      (x25_lapb_receive_frame in net/x25/x25_dev.c).
So logically skb_cow should instead be called before skb_push.

Cc: Eric Dumazet 
Cc: Martin Schiller 
Signed-off-by: Xie He 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

RISC-V: Set maximum number of mapped pages correctly

2020-08-05T07:59:51+00:00

[ Upstream commit d0d8aae64566b753c4330fbd5944b88af035f299 ]

Currently, maximum number of mapper pages are set to the pfn calculated
from the memblock size of the memblock containing kernel. This will work
until that memblock spans the entire memory. However, it will be set to
a wrong value if there are multiple memblocks defined in kernel
(e.g. with efi runtime services).

Set the the maximum value to the pfn calculated from dram size.

Signed-off-by: Atish Patra 
Signed-off-by: Palmer Dabbelt 
Signed-off-by: Sasha Levin

xen-netfront: fix potential deadlock in xennet_remove()

2020-08-05T07:59:51+00:00

[ Upstream commit c2c633106453611be07821f53dff9e93a9d1c3f0 ]

There's a potential race in xennet_remove(); this is what the driver is
doing upon unregistering a network device:

  1. state = read bus state
  2. if state is not "Closed":
  3.    request to set state to "Closing"
  4.    wait for state to be set to "Closing"
  5.    request to set state to "Closed"
  6.    wait for state to be set to "Closed"

If the state changes to "Closed" immediately after step 1 we are stuck
forever in step 4, because the state will never go back from "Closed" to
"Closing".

Make sure to check also for state == "Closed" in step 4 to prevent the
deadlock.

Also add a 5 sec timeout any time we wait for the bus state to change,
to avoid getting stuck forever in wait_event().

Signed-off-by: Andrea Righi 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin