linux-toradex.git/kernel, branch v5.7-rc5

Stop the ad-hoc games with -Wno-maybe-initialized

2020-05-09T20:57:10+00:00

We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds

Merge tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2020-05-08T16:06:34+00:00

Pull driver core fixes from Greg KH:
 "Here are a number of small driver core fixes for 5.7-rc5 to resolve a
  bunch of reported issues with the current tree.

  Biggest here are the reverts and patches from John Stultz to resolve a
  bunch of deferred probe regressions we have been seeing in 5.7-rc
  right now.

  Along with those are some other smaller fixes:

   - coredump crash fix

   - devlink fix for when permissive mode was enabled

   - amba and platform device dma_parms fixes

   - component error silenced for when deferred probe happens

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  regulator: Revert "Use driver_deferred_probe_timeout for regulator_init_complete_work"
  driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires
  driver core: Use dev_warn() instead of dev_WARN() for deferred_probe_timeout warnings
  driver core: Revert default driver_deferred_probe_timeout value to 0
  component: Silence bind error on -EPROBE_DEFER
  driver core: Fix handling of fw_devlink=permissive
  coredump: fix crash when umh is disabled
  amba: Initialize dma_parms for amba devices
  driver core: platform: Initialize dma_parms for platform devices

Merge branch 'akpm' (patches from Andrew)

2020-05-08T15:41:09+00:00

Merge misc fixes from Andrew Morton:
 "14 fixes and one selftest to verify the ipc fixes herein"

* emailed patches from Andrew Morton :
  mm: limit boost_watermark on small zones
  ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST
  mm/vmscan: remove unnecessary argument description of isolate_lru_pages()
  epoll: atomically remove wait entry on wake up
  kselftests: introduce new epoll60 testcase for catching lost wakeups
  percpu: make pcpu_alloc() aware of current gfp context
  mm/slub: fix incorrect interpretation of s->offset
  scripts/gdb: repair rb_first() and rb_last()
  eventpoll: fix missing wakeup for ovflist in ep_poll_callback
  arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin_memory()
  scripts/decodecode: fix trapping instruction formatting
  kernel/kcov.c: fix typos in kcov_remote_start documentation
  mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous()
  mm, memcg: fix error return value of mem_cgroup_css_alloc()
  ipc/mqueue.c: change __do_notify() to bypass check_kill_permission()

kernel/kcov.c: fix typos in kcov_remote_start documentation

2020-05-08T02:27:20+00:00

Signed-off-by: Maciej Grochowski 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrey Konovalov 
Link: http://lkml.kernel.org/r/20200420030259.31674-1-maciek.grochowski@gmail.com
Signed-off-by: Linus Torvalds

Merge tag 'trace-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-05-07T22:27:11+00:00

Pull tracing fixes from Steven Rostedt:

 - Fix bootconfig causing kernels to fail with CONFIG_BLK_DEV_RAM
   enabled

 - Fix allocation leaks in bootconfig tool

 - Fix a double initialization of a variable

 - Fix API bootconfig usage from kprobe boot time events

 - Reject NULL location for kprobes

 - Fix crash caused by preempt delay module not cleaning up kthread
   correctly

 - Add vmalloc_sync_mappings() to prevent x86_64 page faults from
   recursively faulting from tracing page faults

 - Fix comment in gpu/trace kerneldoc header

 - Fix documentation of how to create a trace event class

 - Make the local tracing_snapshot_instance_cond() function static

* tag 'trace-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tools/bootconfig: Fix resource leak in apply_xbc()
  tracing: Make tracing_snapshot_instance_cond() static
  tracing: Fix doc mistakes in trace sample
  gpu/trace: Minor comment updates for gpu_mem_total tracepoint
  tracing: Add a vmalloc_sync_mappings() for safe measure
  tracing: Wait for preempt irq delay thread to finish
  tracing/kprobes: Reject new event if loc is NULL
  tracing/boottime: Fix kprobe event API usage
  tracing/kprobes: Fix a double initialization typo
  bootconfig: Fix to remove bootconfig data from initrd while boot

tracing: Make tracing_snapshot_instance_cond() static

2020-05-07T17:32:58+00:00

Fix the following sparse warning:

kernel/trace/trace.c:950:6: warning: symbol 'tracing_snapshot_instance_cond'
was not declared. Should it be static?

Link: http://lkml.kernel.org/r/1587614905-48692-1-git-send-email-zou_wei@huawei.com

Reported-by: Hulk Robot 
Signed-off-by: Zou Wei 
Signed-off-by: Steven Rostedt (VMware)

tracing: Add a vmalloc_sync_mappings() for safe measure

2020-05-07T17:32:57+00:00

x86_64 lazily maps in the vmalloc pages, and the way this works with per_cpu
areas can be complex, to say the least. Mappings may happen at boot up, and
if nothing synchronizes the page tables, those page mappings may not be
synced till they are used. This causes issues for anything that might touch
one of those mappings in the path of the page fault handler. When one of
those unmapped mappings is touched in the page fault handler, it will cause
another page fault, which in turn will cause a page fault, and leave us in
a loop of page faults.

Commit 763802b53a42 ("x86/mm: split vmalloc_sync_all()") split
vmalloc_sync_all() into vmalloc_sync_unmappings() and
vmalloc_sync_mappings(), as on system exit, it did not need to do a full
sync on x86_64 (although it still needed to be done on x86_32). By chance,
the vmalloc_sync_all() would synchronize the page mappings done at boot up
and prevent the per cpu area from being a problem for tracing in the page
fault handler. But when that synchronization in the exit of a task became a
nop, it caused the problem to appear.

Link: https://lore.kernel.org/r/20200429054857.66e8e333@oasis.local.home

Cc: stable@vger.kernel.org
Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Reported-by: "Tzvetomir Stoyanov (VMware)" 
Suggested-by: Joerg Roedel 
Signed-off-by: Steven Rostedt (VMware)

tracing: Wait for preempt irq delay thread to finish

2020-05-07T17:32:40+00:00

Running on a slower machine, it is possible that the preempt delay kernel
thread may still be executing if the module was immediately removed after
added, and this can cause the kernel to crash as the kernel thread might be
executing after its code has been removed.

There's no reason that the caller of the code shouldn't just wait for the
delay thread to finish, as the thread can also be created by a trigger in
the sysfs code, which also has the same issues.

Link: http://lore.kernel.org/r/5EA2B0C8.2080706@cn.fujitsu.com

Cc: stable@vger.kernel.org
Fixes: 793937236d1ee ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Reported-by: Xiao Yang 
Reviewed-by: Xiao Yang 
Reviewed-by: Joel Fernandes 
Signed-off-by: Steven Rostedt (VMware)

tracing/kprobes: Reject new event if loc is NULL

2020-05-06T13:04:11+00:00

Reject the new event which has NULL location for kprobes.
For kprobes, user must specify at least the location.

Link: http://lkml.kernel.org/r/158779376597.6082.1411212055469099461.stgit@devnote2

Cc: Tom Zanussi 
Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions")
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/boottime: Fix kprobe event API usage

2020-05-06T13:04:11+00:00

Fix boottime kprobe events to use API correctly for
multiple events.

For example, when we set a multiprobe kprobe events in
bootconfig like below,

  ftrace.event.kprobes.myevent {
  	probes = "vfs_read $arg1 $arg2", "vfs_write $arg1 $arg2"
  }

This cause an error;

  trace_boot: Failed to add probe: p:kprobes/myevent (null)  vfs_read $arg1 $arg2  vfs_write $arg1 $arg2

This shows the 1st argument becomes NULL and multiprobes
are merged to 1 probe.

Link: http://lkml.kernel.org/r/158779375766.6082.201939936008972838.stgit@devnote2

Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Fixes: 29a154810546 ("tracing: Change trace_boot to use kprobe_event interface")
Reviewed-by: Tom Zanussi 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)