linux-stable.git/kernel, branch v4.19.5

sched/core: Take the hotplug lock in sched_init_smp()

2018-11-27T15:13:06+00:00

[ Upstream commit 40fa3780bac2b654edf23f6b13f4e2dd550aea10 ]

When running on linux-next (8c60c36d0b8c ("Add linux-next specific files
for 20181019")) + CONFIG_PROVE_LOCKING=y on a big.LITTLE system (e.g.
Juno or HiKey960), we get the following report:

 [    0.748225] Call trace:
 [    0.750685]  lockdep_assert_cpus_held+0x30/0x40
 [    0.755236]  static_key_enable_cpuslocked+0x20/0xc8
 [    0.760137]  build_sched_domains+0x1034/0x1108
 [    0.764601]  sched_init_domains+0x68/0x90
 [    0.768628]  sched_init_smp+0x30/0x80
 [    0.772309]  kernel_init_freeable+0x278/0x51c
 [    0.776685]  kernel_init+0x10/0x108
 [    0.780190]  ret_from_fork+0x10/0x18

The static_key in question is 'sched_asym_cpucapacity' introduced by
commit:

  df054e8445a4 ("sched/topology: Add static_key for asymmetric CPU capacity optimizations")

In this particular case, we enable it because smp_prepare_cpus() will
end up fetching the capacity-dmips-mhz entry from the devicetree,
so we already have some asymmetry detected when entering sched_init_smp().

This didn't get detected in tip/sched/core because we were missing:

  commit cb538267ea1e ("jump_label/lockdep: Assert we hold the hotplug lock for _cpuslocked() operations")

Calls to build_sched_domains() post sched_init_smp() will hold the
hotplug lock, it just so happens that this very first call is a
special case. As stated by a comment in sched_init_smp(), "There's no
userspace yet to cause hotplug operations" so this is a harmless
warning.

However, to both respect the semantics of underlying
callees and make lockdep happy, take the hotplug lock in
sched_init_smp(). This also satisfies the comment atop
sched_init_domains() that says "Callers must hold the hotplug lock".

Reported-by: Sudeep Holla 
Tested-by: Sudeep Holla 
Signed-off-by: Valentin Schneider 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: morten.rasmussen@arm.com
Cc: quentin.perret@arm.com
Link: http://lkml.kernel.org/r/1540301851-3048-1-git-send-email-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

bpf: fix bpf_prog_get_info_by_fd to return 0 func_lens for unpriv

2018-11-27T15:13:03+00:00

[ Upstream commit 28c2fae726bf5003cd209b0d5910a642af98316f ]

While dbecd7388476 ("bpf: get kernel symbol addresses via syscall")
zeroed info.nr_jited_ksyms in bpf_prog_get_info_by_fd() for queries
from unprivileged users, commit 815581c11cc2 ("bpf: get JITed image
lengths of functions via syscall") forgot about doing so and therefore
returns the #elems of the user set up buffer which is incorrect. It
also needs to indicate a info.nr_jited_func_lens of zero.

Fixes: 815581c11cc2 ("bpf: get JITed image lengths of functions via syscall")
Signed-off-by: Daniel Borkmann 
Cc: Sandipan Das 
Cc: Song Liu 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

Revert "x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation"

2018-11-23T07:17:07+00:00

This reverts commit 233b9d7df0e114c7e7c3674559fb0fc41ada3e8f which is
commit 53c613fe6349994f023245519265999eed75957f upstream.

It's not ready for the stable trees as there are major slowdowns
involved with this patch.

Reported-by: Jiri Kosina 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Josh Poimboeuf 
Cc: Andrea Arcangeli 
Cc:  "WoodhouseDavid" 
Cc: Andi Kleen 
Cc: Tim Chen 
Cc:  "SchauflerCasey" 
Signed-off-by: Greg Kroah-Hartman

kdb: print real address of pointers instead of hashed addresses

2018-11-21T08:19:23+00:00

commit 568fb6f42ac6851320adaea25f8f1b94de14e40a upstream.

Since commit ad67b74d2469 ("printk: hash addresses printed with %p"),
all pointers printed with %p are printed with hashed addresses
instead of real addresses in order to avoid leaking addresses in
dmesg and syslog. But this applies to kdb too, with is unfortunate:

    Entering kdb (current=0x(ptrval), pid 329) due to Keyboard Entry
    kdb> ps
    15 sleeping system daemon (state M) processes suppressed,
    use 'ps A' to see all.
    Task Addr       Pid   Parent [*] cpu State Thread     Command
    0x(ptrval)      329      328  1    0   R  0x(ptrval) *sh

    0x(ptrval)        1        0  0    0   S  0x(ptrval)  init
    0x(ptrval)        3        2  0    0   D  0x(ptrval)  rcu_gp
    0x(ptrval)        4        2  0    0   D  0x(ptrval)  rcu_par_gp
    0x(ptrval)        5        2  0    0   D  0x(ptrval)  kworker/0:0
    0x(ptrval)        6        2  0    0   D  0x(ptrval)  kworker/0:0H
    0x(ptrval)        7        2  0    0   D  0x(ptrval)  kworker/u2:0
    0x(ptrval)        8        2  0    0   D  0x(ptrval)  mm_percpu_wq
    0x(ptrval)       10        2  0    0   D  0x(ptrval)  rcu_preempt

The whole purpose of kdb is to debug, and for debugging real addresses
need to be known. In addition, data displayed by kdb doesn't go into
dmesg.

This patch replaces all %p by %px in kdb in order to display real
addresses.

Fixes: ad67b74d2469 ("printk: hash addresses printed with %p")
Cc: 
Signed-off-by: Christophe Leroy 
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

kdb: use correct pointer when 'btc' calls 'btt'

2018-11-21T08:19:23+00:00

commit dded2e159208a9edc21dd5c5f583afa28d378d39 upstream.

On a powerpc 8xx, 'btc' fails as follows:

Entering kdb (current=0x(ptrval), pid 282) due to Keyboard Entry
kdb> btc
btc: cpu status: Currently on cpu 0
Available cpus: 0
kdb_getarea: Bad address 0x0

when booting the kernel with 'debug_boot_weak_hash', it fails as well

Entering kdb (current=0xba99ad80, pid 284) due to Keyboard Entry
kdb> btc
btc: cpu status: Currently on cpu 0
Available cpus: 0
kdb_getarea: Bad address 0xba99ad80

On other platforms, Oopses have been observed too, see
https://github.com/linuxppc/linux/issues/139

This is due to btc calling 'btt' with %p pointer as an argument.

This patch replaces %p by %px to get the real pointer value as
expected by 'btt'

Fixes: ad67b74d2469 ("printk: hash addresses printed with %p")
Cc: 
Signed-off-by: Christophe Leroy 
Reviewed-by: Daniel Thompson 
Signed-off-by: Daniel Thompson 
Signed-off-by: Greg Kroah-Hartman

tracing/kprobes: Check the probe on unloaded module correctly

2018-11-21T08:19:09+00:00

[ Upstream commit 59158ec4aef7d44be51a6f3e7e17fc64c32604eb ]

Current kprobe event doesn't checks correctly whether the
given event is on unloaded module or not. It just checks
the event has ":" in the name.

That is not enough because if we define a probe on non-exist
symbol on loaded module, it allows to define that (with
warning message)

To ensure it correctly, this searches the module name on
loaded module list and only if there is not, it allows to
define it. (this event will be available when the target
module is loaded)

Link: http://lkml.kernel.org/r/153547309528.26502.8300278470528281328.stgit@devbox

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

bpf: wait for running BPF programs when updating map-in-map

2018-11-13T19:09:00+00:00

commit 1ae80cf31938c8f77c37a29bbe29e7f1cd492be8 upstream.

The map-in-map frequently serves as a mechanism for atomic
snapshotting of state that a BPF program might record.  The current
implementation is dangerous to use in this way, however, since
userspace has no way of knowing when all programs that might have
retrieved the "old" value of the map may have completed.

This change ensures that map update operations on map-in-map map types
always wait for all references to the old map to drop before returning
to userspace.

Signed-off-by: Daniel Colascione 
Reviewed-by: Joel Fernandes (Google) 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Chenbo Feng 
Signed-off-by: Greg Kroah-Hartman

userns: also map extents in the reverse map to kernel IDs

2018-11-13T19:09:00+00:00

commit d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd upstream.

The current logic first clones the extent array and sorts both copies, then
maps the lower IDs of the forward mapping into the lower namespace, but
doesn't map the lower IDs of the reverse mapping.

This means that code in a nested user namespace with >5 extents will see
incorrect IDs. It also breaks some access checks, like
inode_owner_or_capable() and privileged_wrt_inode_uidgid(), so a process
can incorrectly appear to be capable relative to an inode.

To fix it, we have to make sure that the "lower_first" members of extents
in both arrays are translated; and we have to make sure that the reverse
map is sorted *after* the translation (since otherwise the translation can
break the sorting).

This is CVE-2018-18955.

Fixes: 6397fac4915a ("userns: bump idmap limits to 340")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn 
Tested-by: Eric W. Biederman 
Reviewed-by: Eric W. Biederman 
Signed-off-by: Eric W. Biederman 
Signed-off-by: Greg Kroah-Hartman

tracing: Return -ENOENT if there is no target synthetic event

2018-11-13T19:08:56+00:00

commit 18858511fd8a877303cc34c06efa461b26a0e070 upstream.

Return -ENOENT error if there is no target synthetic event.
This notices an operation failure to user as below;

  # echo 'wakeup_latency u64 lat; pid_t pid;' > synthetic_events
  # echo '!wakeup' >> synthetic_events
  sh: write error: No such file or directory

Link: http://lkml.kernel.org/r/154013449986.25576.9487131386597290172.stgit@devbox

Acked-by: Tom Zanussi 
Tested-by: Tom Zanussi 
Cc: Shuah Khan 
Cc: Rajvi Jingar 
Cc: stable@vger.kernel.org
Fixes: 4b147936fa50 ('tracing: Add support for 'synthetic' events')
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

genirq: Fix race on spurious interrupt detection

2018-11-13T19:08:48+00:00

commit 746a923b863a1065ef77324e1e43f19b1a3eab5c upstream.

Commit 1e77d0a1ed74 ("genirq: Sanitize spurious interrupt detection of
threaded irqs") made detection of spurious interrupts work for threaded
handlers by:

a) incrementing a counter every time the thread returns IRQ_HANDLED, and
b) checking whether that counter has increased every time the thread is
   woken.

However for oneshot interrupts, the commit unmasks the interrupt before
incrementing the counter.  If another interrupt occurs right after
unmasking but before the counter is incremented, that interrupt is
incorrectly considered spurious:

time
 |  irq_thread()
 |    irq_thread_fn()
 |      action->thread_fn()
 |      irq_finalize_oneshot()
 |        unmask_threaded_irq()            /* interrupt is unmasked */
 |
 |                  /* interrupt fires, incorrectly deemed spurious */
 |
 |    atomic_inc(&desc->threads_handled); /* counter is incremented */
 v

This is observed with a hi3110 CAN controller receiving data at high volume
(from a separate machine sending with "cangen -g 0 -i -x"): The controller
signals a huge number of interrupts (hundreds of millions per day) and
every second there are about a dozen which are deemed spurious.

In theory with high CPU load and the presence of higher priority tasks, the
number of incorrectly detected spurious interrupts might increase beyond
the 99,900 threshold and cause disablement of the interrupt.

In practice it just increments the spurious interrupt count. But that can
cause people to waste time investigating it over and over.

Fix it by moving the accounting before the invocation of
irq_finalize_oneshot().

[ tglx: Folded change log update ]

Fixes: 1e77d0a1ed74 ("genirq: Sanitize spurious interrupt detection of threaded irqs")
Signed-off-by: Lukas Wunner 
Signed-off-by: Thomas Gleixner 
Cc: Mathias Duckeck 
Cc: Akshay Bhat 
Cc: Casey Fitzpatrick 
Cc: stable@vger.kernel.org # v3.16+
Link: https://lkml.kernel.org/r/1dfd8bbd16163940648045495e3e9698e63b50ad.1539867047.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman