linux-stable.git/kernel/trace, branch linux-5.9.y

tracing: Fix userstacktrace option for instances

2020-12-11T12:22:08+00:00

commit bcee5278958802b40ee8b26679155a6d9231783e upstream.

When the instances were able to use their own options, the userstacktrace
option was left hardcoded for the top level. This made the instance
userstacktrace option bascially into a nop, and will confuse users that set
it, but nothing happens (I was confused when it happened to me!)

Cc: stable@vger.kernel.org
Fixes: 16270145ce6b ("tracing: Add trace options for core options to instances")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Fix DYNAMIC_FTRACE_WITH_DIRECT_CALLS dependency

2020-12-11T12:22:06+00:00

commit 49a962c075dfa41c78e34784772329bc8784d217 upstream.

DYNAMIC_FTRACE_WITH_DIRECT_CALLS should depend on
DYNAMIC_FTRACE_WITH_REGS since we need ftrace_regs_caller().

Link: https://lkml.kernel.org/r/fc4b257ea8689a36f086d2389a9ed989496ca63a.1606412433.git.naveen.n.rao@linux.vnet.ibm.com

Cc: stable@vger.kernel.org
Fixes: 763e34e74bb7d5c ("ftrace: Add register_ftrace_direct()")
Signed-off-by: Naveen N. Rao 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Fix updating FTRACE_FL_TRAMP

2020-12-11T12:22:06+00:00

commit 4c75b0ff4e4bf7a45b5aef9639799719c28d0073 upstream.

On powerpc, kprobe-direct.tc triggered FTRACE_WARN_ON() in
ftrace_get_addr_new() followed by the below message:
  Bad trampoline accounting at: 000000004222522f (wake_up_process+0xc/0x20) (f0000001)

The set of steps leading to this involved:
- modprobe ftrace-direct-too
- enable_probe
- modprobe ftrace-direct
- rmmod ftrace-direct <-- trigger

The problem turned out to be that we were not updating flags in the
ftrace record properly. From the above message about the trampoline
accounting being bad, it can be seen that the ftrace record still has
FTRACE_FL_TRAMP set though ftrace-direct module is going away. This
happens because we are checking if any ftrace_ops has the
FTRACE_FL_TRAMP flag set _before_ updating the filter hash.

The fix for this is to look for any _other_ ftrace_ops that also needs
FTRACE_FL_TRAMP.

Link: https://lkml.kernel.org/r/56c113aa9c3e10c19144a36d9684c7882bf09af5.1606412433.git.naveen.n.rao@linux.vnet.ibm.com

Cc: stable@vger.kernel.org
Fixes: a124692b698b0 ("ftrace: Enable trampoline when rec count returns back to one")
Signed-off-by: Naveen N. Rao 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ring-buffer: Always check to put back before stamp when crossing pages

2020-12-11T12:22:06+00:00

commit 68e10d5ff512b503dcba1246ad5620f32035e135 upstream.

The current ring buffer logic checks to see if the updating of the event
buffer was interrupted, and if it is, it will try to fix up the before stamp
with the write stamp to make them equal again. This logic is flawed, because
if it is not interrupted, the two are guaranteed to be different, as the
current event just updated the before stamp before allocation. This
guarantees that the next event (this one or another interrupting one) will
think it interrupted the time updates of a previous event and inject an
absolute time stamp to compensate.

The correct logic is to always update the timestamps when traversing to a
new sub buffer.

Cc: stable@vger.kernel.org
Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ring-buffer: Set the right timestamp in the slow path of __rb_reserve_next()

2020-12-11T12:22:06+00:00

commit 8785f51a17083eee7c37606079c6447afc6ba102 upstream.

In the slow path of __rb_reserve_next() a nested event(s) can happen
between evaluating the timestamp delta of the current event and updating
write_stamp via local_cmpxchg(); in this case the delta is not valid
anymore and it should be set to 0 (same timestamp as the interrupting
event), since the event that we are currently processing is not the last
event in the buffer.

Link: https://lkml.kernel.org/r/X8IVJcp1gRE+FJCJ@xps-13-7390

Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: stable@vger.kernel.org
Link: https://lwn.net/Articles/831207
Fixes: a389d86f7fd0 ("ring-buffer: Have nested events still record running time stamp")
Signed-off-by: Andrea Righi 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ring-buffer: Update write stamp with the correct ts

2020-12-11T12:22:05+00:00

commit 55ea4cf403800af2ce6b125bc3d853117e0c0456 upstream.

The write stamp, used to calculate deltas between events, was updated with
the stale "ts" value in the "info" structure, and not with the updated "ts"
variable. This caused the deltas between events to be inaccurate, and when
crossing into a new sub buffer, had time go backwards.

Link: https://lkml.kernel.org/r/20201124223917.795844-1-elavila@google.com

Cc: stable@vger.kernel.org
Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp")
Reported-by: "J. Avila" 
Tested-by: Daniel Mentz 
Tested-by: Will McVicker 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing: Remove WARN_ON in start_thread()

2020-12-08T09:42:04+00:00

commit 310e3a4b5a4fc718a72201c1e4cf5c64ac6f5442 upstream.

This patch reverts commit 978defee11a5 ("tracing: Do a WARN_ON()
 if start_thread() in hwlat is called when thread exists")

.start hook can be legally called several times if according
tracer is stopped

screen window 1
[root@localhost ~]# echo 1 > /sys/kernel/tracing/events/kmem/kfree/enable
[root@localhost ~]# echo 1 > /sys/kernel/tracing/options/pause-on-trace
[root@localhost ~]# less -F /sys/kernel/tracing/trace

screen window 2
[root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on
0
[root@localhost ~]# echo hwlat >  /sys/kernel/debug/tracing/current_tracer
[root@localhost ~]# echo 1 > /sys/kernel/debug/tracing/tracing_on
[root@localhost ~]# cat /sys/kernel/debug/tracing/tracing_on
0
[root@localhost ~]# echo 2 > /sys/kernel/debug/tracing/tracing_on

triggers warning in dmesg:
WARNING: CPU: 3 PID: 1403 at kernel/trace/trace_hwlat.c:371 hwlat_tracer_start+0xc9/0xd0

Link: https://lkml.kernel.org/r/bd4d3e70-400d-9c82-7b73-a2d695e86b58@virtuozzo.com

Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Fixes: 978defee11a5 ("tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists")
Signed-off-by: Vasily Averin 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix alignment of static buffer

2020-12-08T09:42:04+00:00

commit 8fa655a3a0013a0c2a2aada6f39a93ee6fc25549 upstream.

With 5.9 kernel on ARM64, I found ftrace_dump output was broken but
it had no problem with normal output "cat /sys/kernel/debug/tracing/trace".

With investigation, it seems coping the data into temporal buffer seems to
break the align binary printf expects if the static buffer is not aligned
with 4-byte. IIUC, get_arg in bstr_printf expects that args has already
right align to be decoded and seq_buf_bprintf says ``the arguments are saved
in a 32bit word array that is defined by the format string constraints``.
So if we don't keep the align under copy to temporal buffer, the output
will be broken by shifting some bytes.

This patch fixes it.

Link: https://lkml.kernel.org/r/20201125225654.1618966-1-minchan@kernel.org

Cc: 
Fixes: 8e99cf91b99bb ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic")
Signed-off-by: Namhyung Kim 
Signed-off-by: Minchan Kim 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

lib/strncpy_from_user.c: Mask out bytes after NUL terminator.

2020-11-24T12:39:05+00:00

[ Upstream commit 6fa6d28051e9fcaa1570e69648ea13a353a5d218 ]

do_strncpy_from_user() may copy some extra bytes after the NUL
terminator into the destination buffer. This usually does not matter for
normal string operations. However, when BPF programs key BPF maps with
strings, this matters a lot.

A BPF program may read strings from user memory by calling the
bpf_probe_read_user_str() helper which eventually calls
do_strncpy_from_user(). The program can then key a map with the
destination buffer. BPF map keys are fixed-width and string-agnostic,
meaning that map keys are treated as a set of bytes.

The issue is when do_strncpy_from_user() overcopies bytes after the NUL
terminator, it can result in seemingly identical strings occupying
multiple slots in a BPF map. This behavior is subtle and totally
unexpected by the user.

This commit masks out the bytes following the NUL while preserving
long-sized stride in the fast path.

Fixes: 6ae08ae3dea2 ("bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers")
Signed-off-by: Daniel Xu 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/21efc982b3e9f2f7b0379eed642294caaa0c27a7.1605642949.git.dxu@dxuuu.xyz
Signed-off-by: Sasha Levin

tracing: Fix the checking of stackidx in __ftrace_trace_stack

2020-11-18T18:22:12+00:00

[ Upstream commit 906695e59324635c62b5ae59df111151a546ca66 ]

The array size is FTRACE_KSTACK_NESTING, so the index FTRACE_KSTACK_NESTING
is illegal too. And fix two typos by the way.

Link: https://lkml.kernel.org/r/20201031085714.2147-1-hqjagain@gmail.com

Signed-off-by: Qiujun Huang 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin