Sergey Senozhatsky 8dcf2dbf65 printk: drop in_nmi check from printk_safe_flush_on_panic() ...

[ Upstream commit 554755be08 ]

Drop the in_nmi() check from printk_safe_flush_on_panic()
and attempt to re-init (IOW unlock) locked logbuf spinlock
from panic CPU regardless of its context.

Otherwise, theoretically, we can deadlock on logbuf trying to flush
per-CPU buffers:

  a) Panic CPU is running in non-NMI context
  b) Panic CPU sends out shutdown IPI via reboot vector
  c) Panic CPU fails to stop all remote CPUs
  d) Panic CPU sends out shutdown IPI via NMI vector
     One of the CPUs that we bring down via NMI vector can hold
     logbuf spin lock (theoretically).

Link: http://lkml.kernel.org/r/20180530070350.10131-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2018-08-03 07:50:24 +02:00

..

bpf

bpf: sockmap, fix leaking maps with attached but not detached progs

2018-04-26 11:02:17 +02:00

cgroup

cgroup: fix rule checking for threaded mode switching

2018-03-28 18:24:37 +02:00

configs

…

debug

kdb: make "mdr" command repeat

2018-05-30 07:52:41 +02:00

events

perf/core: Fix perf_output_read_group()

2018-05-30 07:52:34 +02:00

gcov

…

irq

genirq/affinity: assign vectors to all possible CPUs

2018-07-17 11:39:27 +02:00

livepatch

…

locking

locking/percpu-rwsem: Annotate rwsem ownership transfer by setting RWSEM_OWNER_UNKNOWN

2018-06-21 04:03:00 +09:00

power

PM / hibernate: Fix oops at snapshot_write()

2018-07-17 11:39:32 +02:00

printk

printk: drop in_nmi check from printk_safe_flush_on_panic()

2018-08-03 07:50:24 +02:00

rcu

rcu: Call touch_nmi_watchdog() while printing stall warnings

2018-05-30 07:52:39 +02:00

sched

sched/core: Require cpu_active() in select_task_rq(), for user tasks

2018-07-08 15:30:53 +02:00

time

clocksource: Initialize cs->wd_list

2018-07-22 14:28:48 +02:00

trace

tracing: Quiet gcc warning about maybe unused link variable

2018-08-03 07:50:21 +02:00

.gitignore

…

acct.c

…

async.c

kernel/async.c: revert "async: simplify lowest_in_progress()"

2018-02-16 20:23:05 +01:00

audit_fsnotify.c

…

audit_tree.c

…

audit_watch.c

…

audit.c

audit: return on memory error to avoid null pointer dereference

2018-05-30 07:52:39 +02:00

audit.h

…

auditfilter.c

…

auditsc.c

…

backtracetest.c

…

bounds.c

…

capability.c

…

compat.c

compat: fix 4-byte infoleak via uninitialized struct field

2018-05-16 10:10:26 +02:00

configs.c

…

context_tracking.c

…

cpu_pm.c

…

cpu.c

…

crash_core.c

…

crash_dump.c

…

cred.c

…

delayacct.c

…

dma.c

…

elfcore.c

…

exec_domain.c

…

exit.c

…

extable.c

…

fork.c

fork: unconditionally clear stack on fork

2018-08-03 07:50:20 +02:00

freezer.c

…

futex_compat.c

…

futex.c

…

groups.c

…

hung_task.c

kernel/hung_task.c: show all hung tasks before panic

2018-08-03 07:50:23 +02:00

irq_work.c

…

jump_label.c

…

kallsyms.c

…

kcmp.c

…

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

…

Kconfig.preempt

…

kcov.c

kcov: ensure irq code sees a valid area

2018-08-03 07:50:22 +02:00

kexec_core.c

…

kexec_file.c

…

kexec_internal.h

…

kexec.c

…

kmod.c

…

kprobes.c

…

ksysfs.c

…

kthread.c

kthread, tracing: Don't expose half-written comm when creating kthreads

2018-08-03 07:50:21 +02:00

latencytop.c

…

Makefile

…

memremap.c

mm: Fix memory size alignment in devm_memremap_pages_release()

2018-02-22 15:42:27 +01:00

module_signing.c

…

module-internal.h

…

module.c

init: fix false positives in W+X checking

2018-06-21 04:02:57 +09:00

notifier.c

…

nsproxy.c

…

padata.c

…

panic.c

…

params.c

…

pid_namespace.c

…

pid.c

…

profile.c

…

ptrace.c

…

range.c

…

reboot.c

…

relay.c

kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE

2018-05-30 07:52:00 +02:00

resource.c

resource: fix integer overflow at reallocation

2018-04-24 09:36:22 +02:00

seccomp.c

seccomp: Move speculation migitation control to arch code

2018-05-22 18:54:04 +02:00

signal.c

sched/core: Introduce set_special_state()

2018-06-21 04:02:54 +09:00

smp.c

…

smpboot.c

…

smpboot.h

…

softirq.c

kmemcheck: rip it out

2018-02-22 15:42:24 +01:00

stacktrace.c

…

stop_machine.c

stop_machine: Disable preemption when waking two stopper threads

2018-07-25 11:25:08 +02:00

sys_ni.c

…

sys.c

kernel/sys.c: fix potential Spectre v1 issue

2018-05-30 07:51:50 +02:00

sysctl_binary.c

…

sysctl.c

kmemcheck: rip it out

2018-02-22 15:42:24 +01:00

task_work.c

…

taskstats.c

…

test_kprobes.c

…

torture.c

…

tracepoint.c

tracepoint: Do not warn on ENOMEM

2018-05-09 09:51:50 +02:00

tsacct.c

…

ucount.c

…

uid16.c

…

umh.c

…

up.c

…

user_namespace.c

…

user-return-notifier.c

…

user.c

…

utsname_sysctl.c

…

utsname.c

…

watchdog_hld.c

…

watchdog.c

…

workqueue_internal.h

…

workqueue.c

workqueue: use put_device() instead of kfree()

2018-05-30 07:52:14 +02:00