Subject: linux-next: manual merge of the ftrace tree with Linus' tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 8 Dec 2020 16:02:22 +1100

Hi all,

Today's linux-next merge of the ftrace tree got a conflict in:

  kernel/trace/ring_buffer.c

between commit:

  68e10d5ff512 ("ring-buffer: Always check to put back before stamp when crossing pages")

from Linus' tree and commit:

  5b7be9c709e1 ("ring-buffer: Add test to validate the time stamp deltas")

from the ftrace tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

-- 
Cheers,
Stephen Rothwell

diff --cc kernel/trace/ring_buffer.c
index a6268e09160a,7cd888ee9ac7..000000000000
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@@ -3234,12 -3391,16 +3391,14 @@@ __rb_reserve_next(struct ring_buffer_pe
  
  	/* See if we shot pass the end of this buffer page */
  	if (unlikely(write > BUF_PAGE_SIZE)) {
 -		if (tail != w) {
 -			/* before and after may now different, fix it up*/
 -			b_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before);
 -			a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after);
 -			if (a_ok && b_ok && info->before != info->after)
 -				(void)rb_time_cmpxchg(&cpu_buffer->before_stamp,
 -						      info->before, info->after);
 -		}
 +		/* before and after may now different, fix it up*/
 +		b_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before);
 +		a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after);
 +		if (a_ok && b_ok && info->before != info->after)
 +			(void)rb_time_cmpxchg(&cpu_buffer->before_stamp,
 +					      info->before, info->after);
+ 		if (a_ok && b_ok)
+ 			check_buffer(cpu_buffer, info, CHECK_FULL_PAGE);
  		return rb_move_tail(cpu_buffer, tail, info);
  	}