linux-stable.git/kernel, branch v5.4.15

xdp: Fix cleanup on map free for devmap_hash map type

2020-01-26T09:01:08+00:00

[ Upstream commit 071cdecec57fb5d5df78e6a12114ad7bccea5b0e ]

Tetsuo pointed out that it was not only the device unregister hook that was
broken for devmap_hash types, it was also cleanup on map free. So better
fix this as well.

While we're at it, there's no reason to allocate the netdev_map array for
DEVMAP_HASH, so skip that and adjust the cost accordingly.

Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Reported-by: Tetsuo Handa 
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20191121133612.430414-1-toke@redhat.com
Signed-off-by: Sasha Levin

dma-direct: don't check swiotlb=force in dma_direct_map_resource

2020-01-26T09:01:08+00:00

[ Upstream commit 4268ac6ae5870af10a7417b22990d615f72f77e2 ]

When mapping resources we can't just use swiotlb ram for bounce
buffering.  Switch to a direct dma_capable check instead.

Fixes: cfced786969c ("dma-mapping: remove the default map_resource implementation")
Reported-by: Robin Murphy 
Signed-off-by: Christoph Hellwig 
Acked-by: Marek Szyprowski 
Tested-by: Marek Szyprowski 
Signed-off-by: Sasha Levin

sched/cpufreq: Move the cfs_rq_util_change() call to cpufreq_update_util()

2020-01-26T09:01:08+00:00

[ Upstream commit bef69dd87828ef5d8ecdab8d857cd3a33cf98675 ]

update_cfs_rq_load_avg() calls cfs_rq_util_change() every time PELT decays,
which might be inefficient when the cpufreq driver has rate limitation.

When a task is attached on a CPU, we have this call path:

update_load_avg()
  update_cfs_rq_load_avg()
    cfs_rq_util_change -- > trig frequency update
  attach_entity_load_avg()
    cfs_rq_util_change -- > trig frequency update

The 1st frequency update will not take into account the utilization of the
newly attached task and the 2nd one might be discarded because of rate
limitation of the cpufreq driver.

update_cfs_rq_load_avg() is only called by update_blocked_averages()
and update_load_avg() so we can move the call to
cfs_rq_util_change/cpufreq_update_util() into these two functions.

It's also interesting to note that update_load_avg() already calls
cfs_rq_util_change() directly for the !SMP case.

This change will also ensure that cpufreq_update_util() is called even
when there is no more CFS rq in the leaf_cfs_rq_list to update, but only
IRQ, RT or DL PELT signals.

[ mingo: Minor updates. ]

Reported-by: Doug Smythies 
Tested-by: Doug Smythies 
Signed-off-by: Vincent Guittot 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Dietmar Eggemann 
Acked-by: Rafael J. Wysocki 
Cc: Linus Torvalds 
Cc: Thomas Gleixner 
Cc: juri.lelli@redhat.com
Cc: linux-pm@vger.kernel.org
Cc: mgorman@suse.de
Cc: rostedt@goodmis.org
Cc: sargun@sargun.me
Cc: srinivas.pandruvada@linux.intel.com
Cc: tj@kernel.org
Cc: xiexiuqi@huawei.com
Cc: xiezhipeng1@huawei.com
Fixes: 039ae8bcf7a5 ("sched/fair: Fix O(nr_cgroups) in the load balancing path")
Link: https://lkml.kernel.org/r/1574083279-799-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

workqueue: Add RCU annotation for pwq list walk

2020-01-26T09:01:07+00:00

[ Upstream commit 49e9d1a9faf2f71fdfd80a30697ee9a15070626d ]

An additional check has been recently added to ensure that a RCU related lock
is held while the RCU list is iterated.
The `pwqs' are sometimes iterated without a RCU lock but with the &wq->mutex
acquired leading to a warning.

Teach list_for_each_entry_rcu() that the RCU usage is okay if &wq->mutex
is acquired during the list traversal.

Fixes: 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking")
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Tejun Heo 
Signed-off-by: Sasha Levin

rcu: Fix uninitialized variable in nocb_gp_wait()

2020-01-26T09:01:05+00:00

[ Upstream commit b8889c9c89a2655a231dfed93cc9bdca0930ea67 ]

We never set this to false.  This probably doesn't affect most people's
runtime because GCC will automatically initialize it to false at certain
common optimization levels.  But that behavior is related to a bug in
GCC and obviously should not be relied on.

Fixes: 5d6742b37727 ("rcu/nocb: Use rcu_segcblist for no-CBs CPUs")
Signed-off-by: Dan Carpenter 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Sasha Levin

sched/core: Further clarify sched_class::set_next_task()

2020-01-26T09:01:03+00:00

commit a0e813f26ebcb25c0b5e504498fbd796cca1a4ba upstream.

It turns out there really is something special to the first
set_next_task() invocation. In specific the 'change' pattern really
should not cause balance callbacks.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: juri.lelli@redhat.com
Cc: ktkhai@virtuozzo.com
Cc: mgorman@suse.de
Cc: qais.yousef@arm.com
Cc: qperret@google.com
Cc: rostedt@goodmis.org
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Fixes: f95d4eaee6d0 ("sched/{rt,deadline}: Fix set_next_task vs pick_next_task")
Link: https://lkml.kernel.org/r/20191108131909.775434698@infradead.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

tick/sched: Annotate lockless access to last_jiffies_update

2020-01-23T07:22:55+00:00

commit de95a991bb72e009f47e0c4bbc90fc5f594588d5 upstream.

syzbot (KCSAN) reported a data-race in tick_do_update_jiffies64():

BUG: KCSAN: data-race in tick_do_update_jiffies64 / tick_do_update_jiffies64

write to 0xffffffff8603d008 of 8 bytes by interrupt on cpu 1:
 tick_do_update_jiffies64+0x100/0x250 kernel/time/tick-sched.c:73
 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1292
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline]
 kcsan_setup_watchpoint+0x1d4/0x460 kernel/kcsan/core.c:436
 check_access kernel/kcsan/core.c:466 [inline]
 __tsan_read1 kernel/kcsan/core.c:593 [inline]
 __tsan_read1+0xc2/0x100 kernel/kcsan/core.c:593
 kallsyms_expand_symbol.constprop.0+0x70/0x160 kernel/kallsyms.c:79
 kallsyms_lookup_name+0x7f/0x120 kernel/kallsyms.c:170
 insert_report_filterlist kernel/kcsan/debugfs.c:155 [inline]
 debugfs_write+0x14b/0x2d0 kernel/kcsan/debugfs.c:256
 full_proxy_write+0xbd/0x100 fs/debugfs/file.c:225
 __vfs_write+0x67/0xc0 fs/read_write.c:494
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff8603d008 of 8 bytes by task 0 on cpu 0:
 tick_do_update_jiffies64+0x2b/0x250 kernel/time/tick-sched.c:62
 tick_nohz_update_jiffies kernel/time/tick-sched.c:505 [inline]
 tick_nohz_irq_enter kernel/time/tick-sched.c:1257 [inline]
 tick_irq_enter+0x139/0x1c0 kernel/time/tick-sched.c:1274
 irq_enter+0x4f/0x60 kernel/softirq.c:354
 entering_irq arch/x86/include/asm/apic.h:517 [inline]
 entering_ack_irq arch/x86/include/asm/apic.h:523 [inline]
 smp_apic_timer_interrupt+0x55/0x280 arch/x86/kernel/apic/apic.c:1133
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
 default_idle_call+0x1e/0x40 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x1af/0x280 kernel/sched/idle.c:263
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355
 rest_init+0xec/0xf6 init/main.c:452
 arch_call_rest_init+0x17/0x37
 start_kernel+0x838/0x85e init/main.c:786
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490
 x86_64_start_kernel+0x72/0x76 arch/x86/kernel/head64.c:471
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Use READ_ONCE() and WRITE_ONCE() to annotate this expected race.

Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20191205045619.204946-1-edumazet@google.com
Signed-off-by: Greg Kroah-Hartman

bpf: Fix incorrect verifier simulation of ARSH under ALU32

2020-01-23T07:22:44+00:00

commit 0af2ffc93a4b50948f9dad2786b7f1bd253bf0b9 upstream.

Anatoly has been fuzzing with kBdysch harness and reported a hang in one
of the outcomes:

  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  0: (85) call bpf_get_socket_cookie#46
  1: R0_w=invP(id=0) R10=fp0
  1: (57) r0 &= 808464432
  2: R0_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x30303030)) R10=fp0
  2: (14) w0 -= 810299440
  3: R0_w=invP(id=0,umax_value=4294967295,var_off=(0xcf800000; 0x3077fff0)) R10=fp0
  3: (c4) w0 s>>= 1
  4: R0_w=invP(id=0,umin_value=1740636160,umax_value=2147221496,var_off=(0x67c00000; 0x183bfff8)) R10=fp0
  4: (76) if w0 s>= 0x30303030 goto pc+216
  221: R0_w=invP(id=0,umin_value=1740636160,umax_value=2147221496,var_off=(0x67c00000; 0x183bfff8)) R10=fp0
  221: (95) exit
  processed 6 insns (limit 1000000) [...]

Taking a closer look, the program was xlated as follows:

  # ./bpftool p d x i 12
  0: (85) call bpf_get_socket_cookie#7800896
  1: (bf) r6 = r0
  2: (57) r6 &= 808464432
  3: (14) w6 -= 810299440
  4: (c4) w6 s>>= 1
  5: (76) if w6 s>= 0x30303030 goto pc+216
  6: (05) goto pc-1
  7: (05) goto pc-1
  8: (05) goto pc-1
  [...]
  220: (05) goto pc-1
  221: (05) goto pc-1
  222: (95) exit

Meaning, the visible effect is very similar to f54c7898ed1c ("bpf: Fix
precision tracking for unbounded scalars"), that is, the fall-through
branch in the instruction 5 is considered to be never taken given the
conclusion from the min/max bounds tracking in w6, and therefore the
dead-code sanitation rewrites it as goto pc-1. However, real-life input
disagrees with verification analysis since a soft-lockup was observed.

The bug sits in the analysis of the ARSH. The definition is that we shift
the target register value right by K bits through shifting in copies of
its sign bit. In adjust_scalar_min_max_vals(), we do first coerce the
register into 32 bit mode, same happens after simulating the operation.
However, for the case of simulating the actual ARSH, we don't take the
mode into account and act as if it's always 64 bit, but location of sign
bit is different:

  dst_reg->smin_value >>= umin_val;
  dst_reg->smax_value >>= umin_val;
  dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val);

Consider an unknown R0 where bpf_get_socket_cookie() (or others) would
for example return 0xffff. With the above ARSH simulation, we'd see the
following results:

  [...]
  1: R1=ctx(id=0,off=0,imm=0) R2_w=invP65535 R10=fp0
  1: (85) call bpf_get_socket_cookie#46
  2: R0_w=invP(id=0) R10=fp0
  2: (57) r0 &= 808464432
    -> R0_runtime = 0x3030
  3: R0_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x30303030)) R10=fp0
  3: (14) w0 -= 810299440
    -> R0_runtime = 0xcfb40000
  4: R0_w=invP(id=0,umax_value=4294967295,var_off=(0xcf800000; 0x3077fff0)) R10=fp0
                              (0xffffffff)
  4: (c4) w0 s>>= 1
    -> R0_runtime = 0xe7da0000
  5: R0_w=invP(id=0,umin_value=1740636160,umax_value=2147221496,var_off=(0x67c00000; 0x183bfff8)) R10=fp0
                              (0x67c00000)           (0x7ffbfff8)
  [...]

In insn 3, we have a runtime value of 0xcfb40000, which is '1100 1111 1011
0100 0000 0000 0000 0000', the result after the shift has 0xe7da0000 that
is '1110 0111 1101 1010 0000 0000 0000 0000', where the sign bit is correctly
retained in 32 bit mode. In insn4, the umax was 0xffffffff, and changed into
0x7ffbfff8 after the shift, that is, '0111 1111 1111 1011 1111 1111 1111 1000'
and means here that the simulation didn't retain the sign bit. With above
logic, the updates happen on the 64 bit min/max bounds and given we coerced
the register, the sign bits of the bounds are cleared as well, meaning, we
need to force the simulation into s32 space for 32 bit alu mode.

Verification after the fix below. We're first analyzing the fall-through branch
on 32 bit signed >= test eventually leading to rejection of the program in this
specific case:

  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  0: (b7) r2 = 808464432
  1: R1=ctx(id=0,off=0,imm=0) R2_w=invP808464432 R10=fp0
  1: (85) call bpf_get_socket_cookie#46
  2: R0_w=invP(id=0) R10=fp0
  2: (bf) r6 = r0
  3: R0_w=invP(id=0) R6_w=invP(id=0) R10=fp0
  3: (57) r6 &= 808464432
  4: R0_w=invP(id=0) R6_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x30303030)) R10=fp0
  4: (14) w6 -= 810299440
  5: R0_w=invP(id=0) R6_w=invP(id=0,umax_value=4294967295,var_off=(0xcf800000; 0x3077fff0)) R10=fp0
  5: (c4) w6 s>>= 1
  6: R0_w=invP(id=0) R6_w=invP(id=0,umin_value=3888119808,umax_value=4294705144,var_off=(0xe7c00000; 0x183bfff8)) R10=fp0
                                              (0x67c00000)          (0xfffbfff8)
  6: (76) if w6 s>= 0x30303030 goto pc+216
  7: R0_w=invP(id=0) R6_w=invP(id=0,umin_value=3888119808,umax_value=4294705144,var_off=(0xe7c00000; 0x183bfff8)) R10=fp0
  7: (30) r0 = *(u8 *)skb[808464432]
  BPF_LD_[ABS|IND] uses reserved fields
  processed 8 insns (limit 1000000) [...]

Fixes: 9cbe1f5a32dc ("bpf/verifier: improve register value range tracking with ARSH")
Reported-by: Anatoly Trosinenko 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200115204733.16648-1-daniel@iogearbox.net
Signed-off-by: Greg Kroah-Hartman

locking/lockdep: Fix buffer overrun problem in stack_trace[]

2020-01-23T07:22:39+00:00

commit d91f3057263ceb691ef527e71b41a56b17f6c869 upstream.

If the lockdep code is really running out of the stack_trace entries,
it is likely that buffer overrun can happen and the data immediately
after stack_trace[] will be corrupted.

If there is less than LOCK_TRACE_SIZE_IN_LONGS entries left before
the call to save_trace(), the max_entries computation will leave it
with a very large positive number because of its unsigned nature. The
subsequent call to stack_trace_save() will then corrupt the data after
stack_trace[]. Fix that by changing max_entries to a signed integer
and check for negative value before calling stack_trace_save().

Signed-off-by: Waiman Long 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Bart Van Assche 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 12593b7467f9 ("locking/lockdep: Reduce space occupied by stack traces")
Link: https://lkml.kernel.org/r/20191220135128.14876-1-longman@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

locking/rwsem: Fix kernel crash when spinning on RWSEM_OWNER_UNKNOWN

2020-01-23T07:22:37+00:00

commit 39e7234f00bc93613c086ae42d852d5f4147120a upstream.

The commit 91d2a812dfb9 ("locking/rwsem: Make handoff writer
optimistically spin on owner") will allow a recently woken up waiting
writer to spin on the owner. Unfortunately, if the owner happens to be
RWSEM_OWNER_UNKNOWN, the code will incorrectly spin on it leading to a
kernel crash. This is fixed by passing the proper non-spinnable bits
to rwsem_spin_on_owner() so that RWSEM_OWNER_UNKNOWN will be treated
as a non-spinnable target.

Fixes: 91d2a812dfb9 ("locking/rwsem: Make handoff writer optimistically spin on owner")

Reported-by: Christoph Hellwig 
Signed-off-by: Waiman Long 
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Christoph Hellwig 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200115154336.8679-1-longman@redhat.com
Signed-off-by: Greg Kroah-Hartman